Cisco Systems Network Hardware BC 281 User Manual

Configuring Data-Link Switching Plus  
This chapter describes how to configure data-link switching plus (DLSw+), Cisco’s implementation of  
the DLSw standard for Systems Network Architecture (SNA) and NetBIOS devices. Refer to the DLSw+  
Design and Implementation Guide for more complex configuration instructions. For a complete  
description of the DLSw+ commands mentioned in this chapter, refer to the “DLSw+ Commands”  
chapter of the Cisco IOS Bridging and IBM Networking Command Reference (Volume 1 of 2). To locate  
documentation of other commands that appear in this chapter, use the command reference master index  
or search online.  
This chapter contains the following sections:  
To identify the hardware platform or software image information associated with a feature, use the  
Feature Navigator on Cisco.com to search for information about the feature or refer to the software  
release notes for a specific release. For more information, see the “Identifying Platform Support for  
Cisco IOS Software Features” section on page lv in the “Using Cisco IOS Software” chapter.  
Technology Overview  
DLSw+ is a method of transporting SNA and NetBIOS. It complies with the DLSw standard documented  
in RFC 1795 and the DLSw Version 2 standard. DLSw+ is an alternative to RSRB that addresses several  
inherent problems that exist in RSRB, such as:  
SRB hop-count limits (SRB’s limit is seven)  
Broadcast traffic (including SRB explorer frames or NetBIOS name queries)  
Unnecessary traffic (acknowledgments and keepalives)  
Data-link control timeouts  
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Technology Overview  
UDP Unicast  
DLSw Version 2 uses UDP unicast in response to an IP multicast. When address resolution packets  
(CANUREACH_EX, NETBIOS_NQ_ex, NETBIOS_ANQ, and DATAFRAME) are sent to multiple  
destinations (IP multicast service), DLSw Version 2 sends the response frames (ICANREACH_ex and  
NAME_RECOGNIZED_ex) via UDP unicast.  
UDP unicast uses UDP source port 0. However, some firewall products treat packets that use UDP source  
port 0 as security violations, discarding the packets and preventing DLSw connections. To avoid this  
situation, use one of the following procedures:  
Configure the firewall to allow UDP packets to use UDP source port 0.  
Use the dlsw udp-disable command to disable UDP unicast and send address resolution packets in  
the existing TCP session.  
Enhanced Peer-on-Demand Routing Feature  
DLSw Version 2 establishes TCP connections only when necessary and the TCP connections are brought  
down when there are no circuits to a DLSw peer for a specified amount of time. This method, known as  
peer-on-demand routing, was recently introduced in DLSw Version 2, but has been implemented in Cisco  
DLSw+ border peer technology since Cisco IOS Release 10.3.  
Expedited TCP Connection  
DLSw Version 2 efficiently establishes TCP connections. Previously, DLSw created two unidirectional  
TCP connections and then disconnected one after the capabilities exchange took place. With DLSw  
Version 2, a single bidirectional TCP connection establishes if the peer is brought up as a result of an IP  
multicast/UDP unicast information exchange.  
DLSw+ Features  
DLSw+ is Cisco’s version of DLSw and it supports several additional features and enhancements.  
DLSw+ is a means of transporting SNA and NetBIOS traffic over a campus or WAN. The end systems  
can attach to the network over Token Ring, Ethernet, Synchronous Data Link Control (SDLC) Protocol,  
Qualified Logical Link Control (QLLC), or Fiber Distributed Data Interface (FDDI). See the DLSw+  
Design and Implementation Guide Appendix B, “DLSw+ Support Matrix,” for details. DLSw+ switches  
between diverse media and locally terminates the data links, keeping acknowledgments, keepalives, and  
polling off the WAN. Local termination of data links also eliminates data-link control timeouts that can  
occur during transient network congestion or when rerouting around failed links. Finally, DLSw+  
provides a mechanism for dynamically searching a network for SNA or NetBIOS resources and includes  
caching algorithms that minimize broadcast traffic.  
DLSw+ is fully compatible with any vendor’s RFC 1795 implementation and the following features are  
available when both peers are using DLSw+:  
Peer groups and border peers  
Backup peers  
Promiscuous and on-demand peers  
Explorer firewalls and location learning  
NetBIOS dial-on-demand routing feature support  
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Technology Overview  
UDP unicast support  
Load balancing  
Support for LLC1 circuits  
Support for multiple bridge groups  
Support for RIF Passthrough  
SNA type of service feature support  
Local acknowledgment for Ethernet-attached devices and media conversion for SNA PU 2.1 and  
PU 2.0 devices  
Conversion between LLC2 to SDLC between PU 4 devices  
Local or remote media conversion between LANs and either SDLC Protocol or QLLC  
SNA View, Blue Maps, and Internetwork Status Monitor (ISM) support  
MIB enhancements that allow DLSw+ features to be managed by the CiscoWorks Blue products, SNA  
Maps, and SNA View. Also, new traps alert network management stations of peer or circuit failures. For  
more information, refer to the current Cisco IOS release note for the location of the Cisco MIB website.  
Local Acknowledgment  
When you have LANs separated by wide geographic distances, and you want to avoid sending data  
multiple times, and the loss of user sessions that can occur with time delays, encapsulate the source-route  
bridged traffic inside IP datagrams passed over a TCP connection between two routers with local  
acknowledgment enabled.  
Logical Link Control, type 2 (LLC2) is an ISO standard data-link level protocol used in Token Ring  
networks. LLC2 was designed to provide reliable sending of data across LAN media and to cause  
minimal or at least predictable time delays. However, DLSw+ and WAN backbones created LANs that  
are separated by wide, geographic distances-spanning countries and continents. As a result, LANs have  
time delays that are longer than LLC2 allows for bidirectional communication between hosts. Local  
acknowledgment addresses the problem of unpredictable time delays, multiple sendings, and loss of user  
sessions.  
In a typical LLC2 session, when one host sends a frame to another host, the sending host expects the  
receiving host to respond positively or negatively in a predefined period of time commonly called the T1  
time. If the sending host does not receive an acknowledgment of the frame it sent within the T1 time, it  
retries a few times (normally 8 to 10). If there is still no response, the sending host drops the session.  
Figure 127 illustrates an LLC2 session in which a 37x5 on a LAN segment communicates with a 3x74  
on a different LAN segment separated via a wide-area backbone network. Frames are transported  
between Router A and Router B by means of DLSw+. However, the LLC2 session between the 37x5 and  
the 3x74 is still end-to-end; that is, every frame generated by the 37x5 traverses the backbone network  
to the 3x74, and the 3x74, on receipt of the frame, acknowledges it.  
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Technology Overview  
Figure 127 LLC2 Session w ithout Local Acknow ledgm ent  
Router B  
Router A  
Token  
Ring  
Token  
Ring  
WAN  
37x5  
3x74  
LLC2 session  
SNA session  
On backbone networks consisting of slow serial links, the T1 timer on end hosts could expire before the  
frames reach the remote hosts, causing the end host to resend. Resending results in duplicate frames  
reaching the remote host at the same time as the first frame reaches the remote host. Such frame  
duplication breaks the LLC2 protocol, resulting in the loss of sessions between the two IBM machines.  
One way to solve this time delay is to increase the timeout value on the end nodes to account for the  
maximum transit time between the two end machines. However, in networks consisting of hundreds or  
even thousands of nodes, every machine would need to be reconfigured with new values. With local  
acknowledgment for LLC2 enabled, the LLC2 session between the two end nodes would not be not  
end-to-end, but instead, would terminate at two local routers. Figure 128 shows the LLC2 session with  
the 37x5 ending at Router A and the LLC2 session with the 3x74 ending at Router B. Both Router A and  
Router B execute the full LLC2 protocol as part of local acknowledgment for LLC2.  
Figure 128 LLC2 Session w ith Local Acknow ledgm ent  
TCP session  
Token  
Ring  
Token  
Ring  
WAN  
37x5  
Router A  
Router B  
3x74  
LLC2 session  
LLC2 session  
SNA session  
With local acknowledgment for LLC2 enabled in both routers, Router A acknowledges frames received  
from the 37x5. The 37x5 still operates as if the acknowledgments it receives are from the 3x74. Router  
A looks like the 3x74 to the 37x5. Similarly, Router B acknowledges frames received from the 3x74. The  
3x74 operates as if the acknowledgments it receives are from the 37x5. Router B looks like the 3x74 to  
37x5. Because the frames do not have to travel the WAN backbone networks to be acknowledged, but  
are locally acknowledged by routers, the end machines do not time out, resulting in no loss of sessions.  
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Technology Overview  
Enabling local acknowledgment for LLC2 has the following advantages:  
Local acknowledgment for LLC2 solves the T1 timer problem without having to change any  
configuration on the end nodes. The end nodes are unaware that the sessions are locally  
acknowledged. In networks consisting of hundreds or even thousands of machines, this is a definite  
advantage. All the frames acknowledged by the Cisco IOS software appear to the end hosts to be  
coming from the remote IBM machine. In fact, by looking at a trace from a protocol analyzer, one  
cannot say whether a frame was acknowledged by the local router or by a remote IBM machine. The  
MAC addresses and the RIFs generated by the Cisco IOS software are identical to those generated  
by the remote IBM machine. The only way to find out whether a session is locally acknowledged is  
to use either a show local-ack command or a show source-bridge command on the router.  
All the supervisory (RR, RNR, REJ) frames that are locally acknowledged go no farther than the  
router. Without local acknowledgment for LLC2, every frame traverses the backbone.  
With local acknowledgment, only data (I-frames) traverse the backbone, resulting in less traffic on  
the backbone network. For installations in which customers pay for the amount of traffic passing  
through the backbone, this could be a definite cost-saving measure. A simple protocol exists  
between the two peers to bring up or down a TCP session.  
Notes on Using LLC2 Local Acknowledgment  
LLC2 local acknowledgment is enabled with TCP and DLSw+ Lite remote peers.  
If the LLC2 session between the local host and the router terminates in either router, the other will be  
informed to terminate its connection to its local host.  
If the TCP queue length of the connection between the two routers reaches the high-water mark, the  
routers sends Receiver-Not-Ready (RNR) messages to the local hosts until the queue limit is reduced to  
below this limit. It is possible, however, to prevent the RNR messages from being sent by using the dlsw  
llc2 nornr command.  
The configuration of the LLC2 parameters for the local Token Ring interfaces can affect overall  
performance. Refer to the chapter “Configuring LLC2 and SDLC Parameters” in this manual for more  
details about fine-tuning your network through the LLC2 parameters.  
The routers at each end of the LLC2 session execute the full LLC2 protocol, which could result in  
significant router overhead. The decision to use local acknowledgment for LLC2 should be based on the  
speed of the backbone network in relation to the Token Ring speed. For LAN segments separated by  
slow-speed serial links (for example, 56 kbps), the T1 timer problem could occur more frequently. In  
such cases, it might be wise to turn on local acknowledgment for LLC2. For LAN segments separated  
by a T1, backbone delays will be minimal; in such cases, DLSw+, FST or direct encapsulation should  
be considered in order to disable local acknowledgement. Speed mismatch between the LAN segments  
and the backbone network is one criterion to help you decide to use local acknowledgment for LLC2.  
There are some situations (such as the receiving host failing between the time the sending host sends  
data and the time the receiving host receives it), in which the sending host would determine, at the LLC2  
layer, that data was received when it actually was not. This error occurs because the router acknowledges  
that it received data from the sending host before it determines that the receiving host can actually  
receive the data. But because both NetBIOS and SNA have error recovery in situations where an end  
device goes down, these higher-level protocols will resend any missing or lost data. Because these  
transaction request/confirmation protocols exist above LLC2, they are not affected by tight timers, as is  
LLC2. They also are transparent to local acknowledgment.  
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Technology Overview  
If you are using NetBIOS applications, note that there are two NetBIOS timers—one at the link level  
and one at the next higher level. Local acknowledgment for LLC2 is designed to solve link timeouts only.  
If you are experiencing NetBIOS session timeouts, you have two options:  
Experiment with increasing your NetBIOS timers and decreasing your maximum NetBIOS frame  
size.  
Avoid using NetBIOS applications on slow serial lines.  
Note  
By default, the Cisco IOS software translates Token Ring LLC2 to Ethernet 802.3 LLC2. To  
configure the router to translate Token Ring LLC2 frames into Ethernet 0x80d5 format frames, refer  
to the section “Enable Token Ring LLC2-to-Ethernet Conversion” in the “Configuring Source-Route  
Bridging” chapter of the Cisco IOS Bridging and IBM Networking Command Reference (Volume 1  
of 2).  
DLSw+ Support for Other SNA Features  
DLSw+ can be used as a transport for SNA features such as LNM, DSPU, SNA service point, and SNA  
Switching Services (SNASw) through a Cisco IOS feature called virtual data-link control (VDLC).  
LNM over DLSw+ allows DLSw+ to be used in Token Ring networks that are managed by IBM’s LNM  
software. Using this feature, LNM can be used to manage Token Ring LANs, control access units, and  
Token Ring attached devices over a DLSw+ network. All management functions continue to operate as  
they would in a source-route bridged network or an RSRB network.  
DSPU over DLSw+ allows Cisco’s DSPU feature to operate in conjunction with DLSw+ in the same  
router. DLSw+ can be used either upstream (toward the mainframe) or downstream (away from the  
mainframe) of DSPU. DSPU concentration consolidates the appearance of multiple PUs into a single PU  
appearance to VTAM, minimizing memory and cycles in central site resources (VTAM, NCP, and  
routers) and speeding network startup.  
SNA service point over DLSw+ allows Cisco’s SNA service point feature to be used in conjunction with  
DLSw+ in the same router. Using this feature, SNA service point can be configured in remote routers,  
and DLSw+ can provide the path for the remote service point PU to communicate with NetView. This  
allows full management visibility of resources from a NetView 390 console, while concurrently offering  
the value-added features of DLSw+ in an SNA network.  
SNASw over DLSw+ allows Cisco’s APPN Branch Extender functionality to be used in conjunction with  
DLSw+ in the same router. With this feature, DLSw+ can be used to access SNASw in the data center.  
DLSw+ can also be used as a transport for SNASw upstream connectivity, providing nondisruptive  
recovery from failures.  
Using DLSw+ as a transport for other Cisco IOS SNA features requires a feature called VDLC.  
Cisco IOS data-link users (such as LNM, DSPU, SNA service point, and SNASw) write to a virtual  
data-link control interface. DLSw+ then reads from this interface and sends out the traffic. Similarly,  
DLSw+ can receive traffic destined for one of these data-link users and write it to the virtual data-link  
control interface, from which the appropriate data-link user will read it.  
In Figure 129, SNASw and DLSw+ use Token Ring and Ethernet, respectively, as “real” data-link  
controls, and use virtual data-link control to communicate between themselves. When one of the  
high-layer protocols passes data to the virtual data-link control, the virtual data-link control must pass  
it to a higher-layer protocol; nothing leaves the virtual data-link control without going through a  
data-link user.  
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Figure 129 VDLC Interaction w ith Higher-Layer Protocols  
DLSw+  
Data-link users  
SNASw  
CLSI  
Token  
Ring  
Data-link controls  
Ethernet  
VDLC  
The higher-layer protocols make no distinction between the VDLC and any other data-link control, but  
they do identify the VDLC as a destination. In the example shown in Figure 129, SNASw has two ports:  
a physical port for Token Ring and a virtual port for the VDLC. When you define the SNASw VDLC  
port, you can specify the MAC address assigned to it. Data transport from SNASw to DLSw+ by way of  
the VDLC is directed to the VDLC MAC address. The type of higher-layer protocol you use determines  
how the VDLC MAC address is assigned.  
DLSw+ Configuration Task List  
DLSw+ supports local or remote media conversion between LANs and SDLC or QLLC.  
To configure DLSw+, complete the tasks in the following sections:  
Defining a DLSw+ Local Peer for the Router  
Defining a DLSw+ local peer for a router enables DLSw+. Specify all local DLSw+ parameters as part  
of the local peer definition. To define a local peer, use the following command in global configuration  
mode:  
Command  
Purpose  
Router(config)# dlsw local peer [peer-id  
ip-address] [group group] [border] [cluster  
cluster-id] [cost cost] [lf size] [keepalive  
seconds] [passive] [promiscuous]  
Defines the DLSw+ local peer.  
[init-pacing-window size] [max-pacing-window  
size] [biu-segment]  
The following is a sample dlsw local peer statement:  
dlsw local peer peer-id 10.2.34.3  
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Defining a DLSw+ Remote Peer  
Defining a remote peer in DLSw+ is optional, however, usually at least one side of a peer connection has  
a dlsw remote-peer statement. If you omit the dlsw remote-peer command from a DLSw+ peer  
configuration, then you must configure the promiscuous keyword on the dlsw local-peer statement.  
Promiscuous routers will accept any peer connection requests from other routers that are not  
preconfigured. To define a remote peer, use the dlsw remote-peer command in global configuration  
mode.  
One of the options in the remote peer statement is to specify an encapsulation type. Configure one of the  
following types of encapsulations with the dlsw remote-peer statement:  
Which encapsulation type you choose depends on several factors, including whether you want to  
terminate the LLC flows. TCP and DLSw+ Lite terminate the LLC, but the other encapsulation types do  
not. For details on each encapsulation type, see the DLSw+ Design and Implementation Guide. See the  
“Local Acknowledgement” section in the overview chapter of this publication for a discussion on local  
acknowledgement.  
TCP Encapsulation  
To configure TCP encapsulation on a remote peer, use the following command in global configuration  
mode:  
Command  
Purpose  
Router(config)# dlsw remote-peer list-number tcp  
ip-address [  
Defines a remote peer with TCP encapsulation.  
[ip-address | frame-relay interface serial  
number dlci-number | interface name]]  
[bytes-netbios-out bytes-list-name]  
[circuit-weight weight] [cluster cluster-id]  
[cost cost] [dest-mac mac-address]  
[dmac-output-list access-list-number]  
[host-netbios-out host-list-name] [inactivity]  
[dynamic] [keepalive seconds] [lf size] [linger  
minutes] [lsap-output-list list] [no-llc  
minutes] [passive] [priority] [rif-passthru  
virtual-ring-number] [tcp-queue-max size]  
[timeout seconds]  
The following command specifies a dlsw remote peer with TCP encapsulation:  
dlsw remote-peer 0 tcp 10.23.4.5  
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TCP/IP with RIF Passthrough Encapsulation  
To configure TCP/IP with RIF Passthrough encapsulation, use the following command in global  
configuration mode:  
Command  
Purpose  
Router(config)# dlsw remote-peer list-number tcp  
ip-address [backup-peer [ip-address |  
frame-relay interface serial number dlci-number  
|interface name]] [bytes-netbios-out  
bytes-list-name] [circuit-weight weight] [cost  
cost] [dest-mac mac-address] [dmac-output-list  
access-list-number] [host-netbios-out  
host-list-name] [inactivity] [dynamic]  
[keepalive seconds] [lf size] [linger minutes]  
[lsap-output-list list] [no-llc minutes]  
[passive] [priority] [rif-passthru  
Defines a remote peer with TCP/IP with RIF Passthrough  
encapsulation.  
virtual-ring-number] [tcp-queue-max size]  
[timeout seconds]  
The following command specifies a remote peer with TCP/IP with RIF Passthrough encapsulation:  
dlsw remote-peer 0 tcp 10.2.23.5 rif-passthru 100  
FST Encapsulation  
To configure FST encapsulation on a remote peer, use the following command in global configuration  
mode:  
Command  
Purpose  
Router(config)# dlsw remote-peer list-number fst  
ip-address [backup-peer [ip-address |  
frame-relay interface serial number dlci-number  
| interface name]]  
Defines a remote peer with FST encapsulation.  
[bytes-netbios-out bytes-list-name]  
[circuit-weight weight] [cost cost] [dest-mac  
mac-address] [dmac-output-list  
access-list-number] [host-netbios-out  
host-list-name] [keepalive seconds] [lf size]  
[linger minutes] [lsap-output-list list]  
The following command specifies a DLSw remote peer with FST encapsulation:  
dlsw remote-peer 0 fst 10.2.23.5  
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Direct Encapsulation  
To configure direct encapsulation, use the following command in global configuration mode:  
Command  
Purpose  
Defines a remote peer with direct encapsulation.  
Router(config)# dlsw remote-peer list-number  
frame-relay interface serial number dlci-number  
[backup-peer [ip-address | frame-relay interface  
serial number dlci-number | interface name]]  
[bytes-netbios-out bytes-list-name]  
[circuit-weight weight] [cost cost] [dest-mac  
mac-address] [dmac-output-list  
access-list-number] [host-netbios-out  
host-list-name] [keepalive seconds] [lf size]  
[linger minutes] [lsap-output-list list]  
pass-thru  
Direct encapsulation is supported over High-Level Data Link Control (HDLC) and Frame Relay.  
The following command specifies a DLSw remote peer with direct encapsulation over HDLC:  
dlsw remote-peer 0 interface serial 01  
Direct encapsulation over Frame Relay comes in two forms: DLSw Lite (LLC2 encapsulation) and  
Passthrough. Specifying the pass-thru option configures the router so that the traffic will not be locally  
acknowledged. (DLSw+ normally locally acknowledges traffic to keep traffic on the WAN to a  
minimum.)  
The following command specifies a DLSw remote peer with Direct encapsulation with pass-thru over  
Frame Relay:  
dlsw remote-peer 0 frame-relay interface serial 01 pass-thru  
DLSw+ Lite is described in the “DLSw Lite Encapsulation” section on page 291.  
DLSw Lite Encapsulation  
To configure DLSw Lite encapsulation, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw remote-peer list-number  
frame-relay interface serial number dlci-number  
[backup-peer [ip-address | frame-relay interface  
serial number dlci-number | interface name]]  
[bytes-netbios-out bytes-list-name]  
Defines a remote peer with DLSw Lite encapsulation.  
[circuit-weight weight] [cost cost] [dest-mac  
mac-address] [dmac-output-list  
access-list-number] [host-netbios-out  
host-list-name] [keepalive seconds] [lf size]  
[linger minutes] [lsap-output-list list]  
pass-thru  
The following command specifies a DLSw remote peer with DLSw Lite encapsulation over Frame  
Relay:  
dlsw remote-peer 0 frame-relay interface serial 01  
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Mapping DLSw+ to a Local Data-Link Control  
In addition to configuring local and remote peers, you must map one of the following local data-link  
controls to DLSw+:  
Token Ring  
Traffic that originates from Token Ring is source-route bridged from the local ring onto a source-bridge  
ring group and then picked up by DLSw+. You must include a source-bridge ring-group command that  
specifies a virtual ring number when configuring Token Ring with DLSw+. In addition, you must  
configure the source-bridge command that tells the DLSw+ router to bridge from the physical Token  
Ring to the virtual ring.  
To specify a virtual ring number, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# source-bridge ring-group  
ring-group [virtual-mac-address]  
Defines a virtual ring.  
To enable DLSw+ to bridge from the physical Token Ring ring to the virtual ring, use the following  
command in interface mode:  
Command  
Purpose  
Router(config-if)# source-bridge  
source-ring-number bridge-number  
target-ring-number  
Defines SRB on interface.  
To enable single-route explorers, use the following command in interface mode:  
Command  
Purpose  
Router(config-if)# source-bridge spanning  
Enables single-route explorers.  
Configuring the source-bridge spanning command is required because DLSw+ uses single-route  
explorers by default.  
The following command configures a source-bridge ring-group and a virtual ring with a value of  
100 to DLSw+:  
source-bridge ring-group 100  
int T0  
source-bridge 1 1 100  
source-bridge spanning  
The ring-group number specified in the source-bridge command must be the number of a defined  
source-bridge ring-group or DLSw+ will not see this interface.  
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Ethernet  
Traffic that originates from Ethernet is picked up from the local Ethernet interface bridge group and  
transported across the DLSw+ network. Therefore, you must map a specific Ethernet bridge group to  
DLSw+.  
To map an Ethernet bridge group to DLSw+, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw bridge-group group-number  
[llc2 [N2 number] [ack-delay-time milliseconds]  
[ack-max number] [idle-time milliseconds]  
[local-window number] [t1-time milliseconds]  
[tbusy-time milliseconds] [tpf-time  
Links DLSw+ to the bridge group of the Ethernet LAN.  
milliseconds] [trej-time milliseconds]  
[txq-max number] [xid-neg-val-time milliseconds]  
[xid-retry-time milliseconds]] [locaddr-priority  
lu address priority list number] [sap-priority  
priority list number]  
To assign the Ethernet interface to a bridge group, use the following command in interface configuration  
mode:  
Command  
Purpose  
Router(config-if)# bridge-group bridge-group  
Assigns the Ethernet interface to a bridge group.  
The following command maps bridge-group 1 to DLSw+:  
dlsw bridge-group 1  
int E1  
bridge-group 1  
bridge 1 protocol ieee  
SDLC  
Configuring SDLC devices is more complicated than configuring Ethernet and Token Ring. There are  
several considerations that affect which interface commands are configured. See the DLSw+ Design and  
Implementation Guide for more details.  
To establish devices as SDLC stations, use the following commands in interface configuration mode:  
Command  
Purpose  
Router(config-if)# encapsulation  
sdlc  
Step 1  
Step 2  
Step 3  
Step 4  
Step 5  
Sets the encapsulation type of the serial interface to SDLC.  
Router(config-if)# sdlc role {none |  
primary | secondary | prim-xid-poll}  
Establishes the role of the interface.  
Router(config-if)# sdlc vmac  
mac-address1  
Configures a MAC address for the serial interface.  
Assigns a set of secondary stations attached to the serial link.  
Router(config-if)# sdlc address  
hexbyte [echo]  
Router(config-if)# sdlc partner  
mac-address sdlc-address {inbound |  
outbound}  
Specifies the destination address with which an LLC session is  
established for the SDLC station.  
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Command  
Purpose  
Router(config-if)# sdlc xid  
Step 6  
Step 7  
Specifies an XID value appropriate for the designated SDLC station  
associated with this serial interface.  
Router(config-if)# sdlc dlsw  
{sdlc-address | default | partner  
mac-address [inbound | outbound]}  
Enables DLSw+ on an SDLC interface.  
1. The last byte of the MAC address must be 00.  
Use the default option if you have more than 10 SDLC devices to attach to the DLSw+ network. To  
configure an SDLC multidrop line downstream, you configure the SDLC role as either primary or  
prim-xid-poll. SDLC role primary specifies that any PU without the xid-poll parameter in the  
sdlc address command is a PU 2.0 device. SDLC role prim-xid-poll specifies that every PU is type 2.1.  
We recommend that you specify sdlc role primary if all SDLC devices are type PU 2.0 or a mix of  
PU 2.0 and PU 2.1. Specify sdlc role prim-xid-poll if all devices are type PU 2.1.  
To configure DLSw+ to support LLC2-to-SDLC conversion for PU 4 or PU 5 devices, specify the echo  
option in the sdlc address command. A PU 4-to-PU 4 configuration requires that none be specified in  
the sdlc role command.  
on page 319 for sample configurations.  
The following configuration shows a DLSw+ router configured for SDLC:  
dlsw local-peer peer-id 10.2.2.2  
dlsw remote-peer 0 tcp 10.1.1.1  
interface Serial1  
mtu 6000  
no ip address  
encapsulation sdlc  
no keepalive  
nrzi-encoding  
clockrate 9600  
sdlc vmac 4000.3745.0000  
sdlc N1 48016  
sdlc address 04 echo  
sdlc partner 4000.1111.0020 04  
sdlc dlsw 4  
QLLC  
SNA devices use QLLC when connecting to X.25 networks. QLLC essentially emulates SDLC over  
x.25. Therefore, configuring QLLC devices is also complicated. There are several considerations that  
affect which interface commands are configured. See the DLSw+ Design and Implementation Guide for  
details.  
You can configure DLSw+ for QLLC connectivity, which enables both of the following scenarios:  
Remote LAN-attached devices (physical units) or SDLC-attached devices can access an FEP or an  
AS/400 over an X.25 network.  
Our QLLC support allows remote X.25-attached SNA devices to access an FEP without requiring  
X.25 NCP Packet Switching Interface (NPSI) in the FEP. This may eliminate the requirement for  
NPSI (if GATE and DATE are not required), thereby eliminating the recurring license cost. In  
addition, because the QLLC attached devices appear to be Token Ring-attached to the Network  
Control Program (NCP), they require no preconfiguration in the FEP. Remote X.25-attached SNA  
devices can also connect to an AS/400 over Token Ring using this support.  
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Remote X.25-attached SNA devices can access an FEP or an AS/400 over a Token Ring or over  
SDLC.  
For environments just beginning to migrate to LANs, our QLLC support allows deployment of  
LANs in remote sites while maintaining access to the FEP over existing NPSI links. Remote  
LAN-attached devices (physical units) or SDLC-attached devices can access a FEP over an X.25  
network without requiring X.25 hardware or software in the LAN-attached devices. The Cisco IOS  
software supports direct attachment to the FEP over X.25 without the need for routers at the data  
center for SNA traffic.  
To enable QLLC connectivity for DLSw+, use the following commands in interface configuration mode:  
Command  
Purpose  
Router(config-if)# encapsulation x  
25  
Step 1  
Step 2  
Step 3  
Specifies an interface as an X.25 device.  
Router(config-if)# x25 address  
subaddress  
Activates X.25 subaddresses.  
Router(config-if)# x25 map qllc  
virtual-mac-addr x121-addr  
[cud cud-value] [x25-map-options]  
Associates a virtual MAC address with the X.121 address of the remote  
X.25 device.  
Router(config-if)# qllc dlsw  
{subaddress subaddress | pvc pvc-low  
[pvc-high]} [vmac vmacaddr  
[poolsize]] [partner  
Step 4  
Enables DLSw+ over QLLC.  
partner-macaddr] [sap ssap dsap]  
[xid xidstring] [npsi-poll]  
The following configuration enables QLLC connectivity for DLSw+:  
dlsw local-peer peer-id 10.3.12.7  
dlsw remote-peer 0 tcp 10.3.1.4  
interface S0  
encapsulation x25  
x25 address 3110212011  
x25 map qllc 1000.0000.0001 3 1104150101  
qllc dlsw partner 4000.1151.1234  
FDDI  
Configure an FDDI interface the same as a Token Ring or Ethernet interface, depending on whether you  
are configuring SRB or Transparent Bridging. If you are configuring the router for SRB, configure the  
FDDI interface for Token Ring. If you are configuring the router for Transparent Bridging, configure the  
FDDI interface for Ethernet.  
Configuring Advanced Features  
DLSw+ goes beyond the standard to include additional functionality in the following areas:  
Scalability, page 296Constructs IBM internetworks in a way that reduces the amount of broadcast  
traffic, which enhances their scalability.  
Availability, page 303Dynamically finds alternate paths and, optionally, load-balances across  
multiple active peers, ports, and channel gateways.  
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Modes of Operation, page 306Dynamically detects the capabilities of the peer router and operates  
according to those capabilities.  
Network Management, page 307—Works with enhanced network management tools such as  
CiscoWorks Blue Maps, CiscoWorks SNA View, and CiscoWorks Blue Internetwork Status Monitor  
(ISM).  
Traffic Bandwidth and Queueing Management, page 307—Offers several bandwidth management  
and queueing features to enhance the overall performance of your DLSw+ network. Controls  
different types of explorer traffic using multiple queues, each with a wide range of depth settings.  
Access Control, page 307—Provides access control to various resources throughout a network.  
Scalability  
One significant factor that limits the size of Token Ring internet works is the amount of explorer traffic  
that traverses the WAN. DLSw+ includes the following features to reduce the number of explorers:  
Peer Groups and Border Peers  
Perhaps the most significant optimization in DLSw+ is a feature known as peer groups. Peer groups are  
designed to address the broadcast replication that occurs in a fully meshed network. When any-to-any  
communication is required (for example, for NetBIOS or Advanced Peer-to-Peer Networking [APPN]  
environments), RSRB or standard DLSw implementations require peer connections between every pair  
of routers. This setup is not only difficult to configure, but it results in branch access routers having to  
replicate search requests for each peer connection. This setup wastes bandwidth and router cycles. A  
better concept is to group routers into clusters and designate a focal router to be responsible for broadcast  
replication. This capability is included in DLSw+.  
With DLSw+, a cluster of routers in a region or a division of a company can be combined into a peer  
group. Within a peer group, one or more of the routers is designated to be the border peer. Instead of all  
routers peering to one another, each router within a group peers to the border peer; and border peers  
establish peer connections with each other. When a DLSw+ router receives a TEST frame or NetBIOS  
NAME-QUERY, it sends a single explorer frame to its border peer. The DLSw+ border peer router  
checks its local, remote and group cache for any reachability information before forwarding the explorer.  
If no match is found, the border peer forwards the explorer on behalf of the peer group member. If a  
match is found, the border peer sends the explorer to the appropriate peer or border peer. This setup  
eliminates duplicate explorers on the access links and minimizes the processing required in access  
routers.  
You can further segment DLSw+ routers within the same border peer group that are serving the same  
LANs into a peer cluster. This segmentation reduces explorers because the border peer recognizes that  
it only has to forward an explorer to one member within a peer cluster. Only TCP encapsulation can be  
used with the DLSw+ Peer Clusters feature.  
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The DLSw+ Peer Clusters feature is configured locally on the member peer or on a border peer. Although  
both options can be configured, we recommend that the cluster-id of a particular peer is defined in either  
the border peer or on the member peer, but not both because of potential configuration confusion.  
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To define peer groups, configure border peers and assign the local peer to a peer cluster, use the  
following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw local-peer [peer-id  
ip-address] [group group] [border] [cost cost]  
[cluster cluster-id] [lf size] [keepalive  
seconds] [passive] [promiscuous] [biu-segment]  
[init-pacing-window size] [max-pacing-window  
size]  
Enables peer groups and border peers.  
Use the group keyword to define a peer group, the border keyword to define a border peer and the  
cluster keyword to assign the local peer to a peer cluster. When the user defines the cluster option in  
the dlsw local-peer command on the member peer router, the cluster information is exchanged with the  
border peer during the capabilities exchange as the peers become active. The border peer uses this  
information to make explorer replication and forwarding decisions.  
The following command configures the router as the Border peer that is a member of group 2:  
dlsw local-peer peer-id 10.2.13.4 group 2 border  
Configure the cluster option in the dlsw remote-peer command on a border peer to enable the DLSw+  
Peer Clusters feature without forcing every DLSw+ router in the network to upgrade their software. To  
enable the DLSw+ Peer Clusters feature on a Border Peer, use the following command in global  
configuration mode:  
Command  
Purpose  
Router(config)# dlsw remote-peer list-number tcp  
ip-address [backup-peer [ip-address |  
frame-relay interface serial number dlci-number  
|interface name]] [bytes-netbios-out  
bytes-list-name] [circuit-weight weight]  
[cluster cluster-id] [cost cost] [dest-mac  
mac-address] [dmac-output-list  
Defines the border peer router as part of a particular cluster and  
enables the DLSw+ Peer Clusters feature.  
access-list-number] [host-netbios-out  
host-list-name] [inactivity] [dynamic]  
[keepalive seconds] [lf size] [linger minutes]  
[lsap-output-list list] [no-llc minutes]  
[passive] [priority] [rif-passthru  
virtual-ring-number] [tcp-queue-max size]  
[timeout seconds]  
The following command configures a border router as a member of cluster 5:  
dlsw remote-peer tcp 10.2.13.5 cluster 5  
A peer-on-demand peer is a non-configured remote-peer that was connected because of an LLC2 session  
established through a border peer DLSw+ network. On-demand peers greatly reduce the number of peers  
that must be configured. You can use on-demand peers to establish an end-to-end circuit even though the  
DLSw+ routers servicing the end systems have no specific configuration information about the peers.  
This configuration permits casual, any-to-any connection without the burden of configuring the  
connection in advance. It also allows any-to-any switching in large internetworks where persistent TCP  
connections would not be possible.  
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To configure peer-on-demand defaults, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw peer-on-demand-defaults  
[fst] [bytes-netbios-out bytes-list-name] [cost  
cost] [dest-mac destination mac-address]  
[dmac-output-list access-list-number]  
Configures peer-on-demand defaults.  
[host-netbios-out host-list-name] [inactivity  
minutes] [keepalive seconds] [lf size]  
[lsap-output-list list] [port-list  
port-list-number] [priority] [tcp-queue-max]  
To define the maximum entries maintained in a border peer’s group cache, use the following command  
in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw group-cache max-entries  
number  
Defines the maximum entries in a group cache.  
To remove all entries from the DLSw+ reachability cache, use the following command in privileged  
EXEC mode:  
Command  
Purpose  
Router# clear dlsw reachability  
Removes all entries from the DLSw+ reachability cache.  
To reset to zero the number of frames that have been processed in the local, remote and group caches,  
use the following command in privileged EXEC mode:  
Command  
Purpose  
Router# clear dlsw statistics  
Resets to zero the number of frames that have been processed in  
the local, remote, and group caches.  
To disable the border peer caching feature, use the following command in global configuration mode:  
Command  
Purpose  
Router(config-if)# dlsw group-cache disable  
Disables the border peer caching feature.  
To verify that the peer cluster feature is enabled or that the border peer is configured, issue the show  
dlsw capabilities command on the router. To verify the cluster id number of which the peer is a member,  
issue the show dlsw capabilities local command on the local router.  
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To display the contents of the reachability caches, use the following command in privileged EXEC  
command mode:  
Command  
Purpose  
Router# show dlsw reachability [[group [value] |  
local | remote] | [mac-address [address]  
[netbios-names [name]  
Displays content of group, local and remote caches.  
Use the group keyword to display the reachability information for the border peer.  
Explorer Firewalls  
An explorer firewall permits only a single explorer for a particular destination MAC address or NetBIOS  
name to be sent across the WAN. While an explorer is outstanding and awaiting a response from the  
destination, subsequent explorers for that MAC address or NetBIOS name are merely stored. When the  
explorer response is received at the originating DLSw+, all explorers receive an immediate local  
response. This eliminates the start-of-day explorer storm that many networks experience. Configure the  
dlsw timer command to enable explorer firewalls. See the “Configuring DLSw+ Timers” section on  
page 310 for details of the command.  
To enable explorer firewalls, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw timer  
Tunes an existing configuration parameter.  
{icannotreach-block-time | netbios-cache-timeout  
| netbios-explorer-timeout | netbios-group-cache  
| netbios-retry-interval |  
netbios-verify-interval | sna-cache-timeout |  
explorer-delay-time | sna-explorer-timeout |  
explorer-wait-time | sna-group-cache |  
sna-retry-interval | sna-verify-interval} time  
NetBIOS Dial-on-Demand Routing  
This feature allows you to transport NetBIOS in a dial-on-demand routing (DDR) environment by  
filtering NetBIOS Session Alive packets from the WAN. NetBIOS periodically sends Session Alive  
packets as LLC2 I-frames. These packets do not require a response and are superfluous to the function  
of proper data flow. Furthermore, these packets keep dial-on-demand interfaces up and this up time  
causes unwanted per-packet charges in DDR networks. By filtering these NetBIOS Session Alive  
packets, you reduce traffic on the WAN and you reduce some costs that are associated with  
dial-on-demand routing.  
To enable NetBIOS DDR, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw netbios keepalive-filter  
Enables NetBIOS DDR.  
The following command enables NetBIOS DDR:  
dlsw netbios keepalive-filter  
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SNA Dial-on-Demand Routing  
This feature allows you to run DLSw+ over a switched line and have the Cisco IOS software take the  
switched line down dynamically when it is not in use. Utilizing this feature gives the IP Routing table  
more time to converge when a network problem hinders a remote peer connection. In small networks  
with good IP convergence time and ISDN lines that start quickly, it is not as necessary to use the  
keepalive option. To use this feature, you must set the keepalive value to zero, and you may need to use  
a lower value for the timeout option than the default, which is 90 seconds.  
To configure SNA DDR, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw remote-peer list-number tcp  
ip-address [backup-peer [ip-address |  
frame-relay interface serial number dlci-number  
|interface name]] [bytes-netbios-out  
bytes-list-name] [circuit-weight weight]  
[cluster cluster-id] [cost cost] [dest-mac  
mac-address] [dmac-output-list  
Configures SNA DDR.  
access-list-number] [host-netbios-out  
host-list-name] [inactivity] [dynamic]  
[keepalive seconds] [lf size] [linger minutes]  
[lsap-output-list list] [no-llc minutes]  
[passive] [priority] [rif-passthru  
virtual-ring-number] [tcp-queue-max size]  
[timeout seconds]  
The following command configures the SNA DDR feature:  
dlsw remote-peer 0 tcp 10.2.13.4 keepalive 0  
UDP Unicast Feature  
The UDP Unicast feature sends the SSP address resolution packets via UDP unicast service rather than  
TCP. (SSP packets include: CANUREACH_EX, NETBIOS_NQ_ex, NETBIOS_ANQ, and  
DATAFRAME.) The UDP unicast feature allows DLSw+ to better control address resolution packets and  
unnumbered information frames during periods of congestion. Previously, these frames were carried  
over TCP. TCP resends frames that get lost or delayed in transit, and hence aggravate congestion.  
Because address resolution packets and unnumbered information frames are not sent on a reliable  
transport on the LAN, sending them reliably over the WAN is unnecessary. By using UDP for these  
frames, DLSw+ minimizes network congestion.  
Note  
UDP unicast enhancement has no affect on DLSw+ FST or direct peer encapsulation.  
This feature is enabled by default. To disable User Datagram Protocol (UDP) Unicast, use the following  
command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw udp-disable  
Disables UDP Unicast.  
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LLC1 Circuits  
Support for LLC1 circuits more efficiently transports LLC1 UI traffic across a DLSw+ cloud. With  
LLC1 circuit support, the LLC1 unnumbered information frames (UI) are no longer subject to input  
queueing and are guaranteed to traverse the same path for the duration of the flow. This feature improves  
transportation of LLC1 UI traffic because there is no longer the chance of having a specifically routed  
LLC1 UI frame broadcast to all remote peers. The circuit establishment process has not changed except  
that the circuit is established as soon as the specifically routed LLC1 UI frame is received and the  
DLSw+ knows of reachability for the destination MAC address. Furthermore, the connection remains in  
the CIRCUIT_ESTABLISHED state (rather than proceeding to the CONNECT state) until there is no UI  
frame flow for a MAC/SAP pair for 10 minutes.  
This feature is enabled by default.  
Dynamic Peers  
In TCP encapsulation, the dynamic option and its suboptions no-llc and inactivity allow you to specify  
and control the activation of dynamic peers, which are configured peers that are activated only when  
required. Dynamic peer connections are established only when there is DLSw+ data to send. The  
dynamic peer connections are taken down when the last LLC2 connection using them terminates and the  
time period specified in the no-llc option expires. You can also use the inactivity option to take down  
dynamic peers when the circuits using them are inactive for a specified number of minutes.  
Note  
Because the inactivity option may cause active LLC2 sessions to be terminated, you should not use  
this option unless you want active LLC2 sessions to be terminated.  
To configure a dynamic peer, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw remote-peer list-number tcp  
ip-address [backup-peer [ip-address |  
frame-relay interface serial number dlci-number  
| interface name]] [bytes-netbios-out  
bytes-list-name] [circuit-weight weight]  
[cluster cluster-id] [cost cost] [dest-mac  
mac-address] [dmac-output-list  
Configures a dynamic peer.  
access-list-number] [host-netbios-out  
host-list-name] [inactivity] [dynamic]  
[keepalive seconds] [lf size] [linger minutes]  
[lsap-output-list list] [no-llc minutes]  
[passive] [priority] [rif-passthru  
virtual-ring-number] [tcp-queue-max size]  
[timeout seconds]  
The following command specifies a dynamic peer with TCP encapsulation:  
dlsw remote-peer 0 tcp 10.23.4.5 dynamic  
Promiscuous Peer Defaults  
If you do not configure a dlsw remote-peer statement on the DLSw+ router, then you must specify the  
promiscuous keyword on the dlsw local-peer statement. The promiscuous keyword enables the router  
to accept peer connection requests from those routers that are not preconfigured. Setting the dlsw  
prom-peer-defaults command allows the user to determine various settings for the promiscuous  
transport.  
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To configure promiscuous peer defaults, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw prom-peer-defaults  
[bytes-netbios-out bytes-list-name] [cost cost]  
[dest-mac destination-mac-address]  
Configures promiscuous peer defaults.  
[dmac-output-list access-list-number]  
[host-netbios-out host-list-name] [keepalive  
seconds] [lf size] [lsap-output-list list]  
[tcp-queue-max size]  
Availability  
DLSw+ supports the following features that allow it to dynamically finds alternate paths quickly and  
optionally load balances across multiple active peers, ports, and channel gateways:  
Load Balancing  
DLSw+ offers enhanced availability by caching multiple paths to a given MAC address or NetBIOS  
name (where a path is either a remote peer or a local port). Maintaining multiple paths per destination is  
especially attractive in SNA networks. A common technique used in the hierarchical SNA environment  
is assigning the same MAC address to different Token Ring interface couplers (TICs) on the IBM FEPs.  
DLSw+ ensures that duplicate TIC addresses are found, and, if multiple DLSw+ peers can be used to  
reach the FEPs, they are cached.  
The way that multiple capable peers are handled with DLSw+ can be configured to meet either of the  
following network needs:  
Fault tolerance—To rapidly reconnect if a data-link connection is lost. If load balancing is not  
enabled, the Cisco IOS software, by default, maintains a preferred path and one or more capable  
paths to each destination. The preferred path is either the peer or port that responds first to an  
explorer frame or the peer with the least cost. If the preferred path to a given destination is  
unavailable, the next available capable path is promoted to the new preferred path. No additional  
broadcasts are required, and recovery through an alternate peer is immediate. Maintaining multiple  
cache entries facilitates a timely reconnection after session outages.  
A peer with the least cost can also be the preferred path. You can specify cost in either the dlsw local  
peer or dlsw remote peer commands. See the DLSw+ Design and Implementation Guide for details  
on how cost can be applied to control which path sessions use.  
Load balancing—To distribute the network traffic over multiple DLSw+ peers in the network.  
Alternately, when there are duplicate paths to the destination end system, you can configure load  
balancing. DLSw+ alternates new circuit requests in either a round-robin or enhanced load  
balancing fashion through the list of capable peers or ports. If round-robin is configured, the router  
distributes the new circuit in a round-robin fashion, basing it’s decision on which peer or port  
established the last circuit. If enhanced load balancing is configured, the router distributes new  
circuits based on existing loads and the desired ratio. It detects the path that is underloaded in  
comparison to the other capable peers and will assign new circuits to that path until the desired ratio  
is achieved.  
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For multiple peer connections, peer costs must be applied. The DLSw+ Enhanced Load Balancing  
feature works only with the lowest (or equal) cost peers. For example, if the user specifies dlswrtr1,  
dlswrtr2 and dlswrtr3 with costs of 4, 3, and 3 respectively, DLSw+ establishes new circuits with  
only dlswrtr 2 and dlswrtr3.  
To enable the DLSw+ Enhanced Load Balancing feature on the local router, use the following command  
in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw load-balance [round-robin |  
circuit count circuit-weight]  
Configures the DLSw+ Enhanced Load Balancing feature on the  
local router.  
To adjust the circuit weight for a remote peer with TCP encapsulation, use the following command in  
global configuration mode:  
Command  
Purpose  
Router(config)# dlsw remote-peer tcp  
[circuit-weight value]  
Adjusts the circuit weight on the remote peer.  
To adjust the circuit weight for a remote peer with DLSw+ Lite encapsulation, use the following  
command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw remote-peer frame-relay  
interface serial number dlci number  
[circuit-weight value]  
Adjusts the circuit weight on the remote peer.  
The circuit-weight of a remote peer controls the number of circuits that peer can take. If multiple, equally  
low-cost peers can reach a remote source, the circuits to that remote source are distributed among the  
remote peers based on the ratio of their configured circuit-weights. The peer with the highest  
circuit-weight takes more circuits.  
Because a DLSw+ peer selects its new circuit paths from within its reachability cache, the user must  
configure the dlsw timer explorer-wait-time command with enough time to allow for all the explorer  
responses to be received. If the new DLSw+ Enhanced Load Balancing Feature is enabled, a message is  
displayed on the console to alert the user if the timer is not set.  
To configure the amount of time needed for all the explorer responses to be received, use the following  
command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw timer {explorer-wait-time}  
Sets the time to wait for all stations to respond to explorers.  
See the DLSw+ Design and Implementation Guide for details on how to configure load balancing in  
page 327 for a sample configuration.  
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Configuring Data-Link Switching Plus  
DLSw+ Configuration Task List  
Ethernet Redundancy  
The DLSw+ Ethernet Redundancy feature, introduced in Cisco IOS Release 12.0(5)T, provides  
redundancy and load balancing between multiple DLSw+ peers in an Ethernet environment. It enables  
DLSw+ to support parallel paths between two points in an Ethernet environment, ensuring resiliency in  
the case of a router failure and providing load balancing for traffic load. The feature also enables DLSw+  
to support multiple DLSw+ routers on the same transparent bridged domain that can reach the same  
MAC address in a switched environment.  
To enable the DLSw+ Ethernet Redundancy feature, issue the following command in interface  
configuration mode:  
Command  
Purpose  
Router(config-if)# dlsw transparent  
redundancy-enable  
Configures transparent redundancy.  
To enable the DLSw+ Ethernet Redundancy feature in a switched environment, enter the following  
commands in interface configuration mode:  
Command  
Purpose  
Router(config-if)# dlsw transparent  
switch-support  
Step 1  
Step 2  
Enables DLSw+ Ethernet Redundancy feature when using a switch  
device.  
Router(config-if)# dlsw transparent  
map local mac mac address remote mac  
mac address neighbor mac address  
Configures a single destination MAC address to which multiple MAC  
addresses on a transparent bridged are mapped.  
The Ethernet Redundancy feature is a complex feature. See the DLSw+ Design and Implementation  
Backup Peers  
The backup-peer option is common to all encapsulation types on a remote peer and specifies that this  
remote peer is a backup peer for the router with the specified IP-address, Frame Relay Data-Link Control  
Identifier (DLCI) number, or interface name. When the primary peer fails, all circuits over this peer are  
disconnected and the user can start a new session via their backup peer. Prior to Cisco IOS  
Release 11.2(6)F, you could configure backup peers only for primary FST and TCP.  
Also, when you specify the backup-peer option in a dlsw remote-peer tcp command, the backup peer  
is activated only when the primary peer becomes unreachable. Once the primary peer is reactivated, all  
new sessions use the primary peer and the backup peer remains active only as long as there are LLC2  
connections using it. You can use the linger option to specify a period (in minutes) that the backup peer  
remains connected after the connection to the primary peer is reestablished. When the linger period  
expires, the backup peer connection is taken down.  
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Configuring Data-Link Switching Plus  
DLSw+ Configuration Task List  
Note  
If the linger keyword is set to 0, all existing sessions on the backup router immediately drop when  
the primary recovers. If the linger keyword is omitted, all existing sessions on the backup router  
remain active (as long as the session is active) when the primary recovers, however, all new sessions  
establish via the primary peer. If the linger keyword is set to  
x minutes, all existing sessions on the backup router remain active for x minutes once the primary  
recovers, however, all new sessions establish via the primary peer. Once x minutes expire, all existing  
sessions on the backup router drop and the backup peer connection is terminated. The linger keyword  
can be used to minimize line costs if the backup peer is accessed over dial lines, but can be set high  
enough to allow an operator warning to be sent to all the SNA end users. It will not, however, pass  
explorers and will not create any new circuits while the primary is up.  
To configure a backup peer, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw remote peer backup-peer  
ip-address  
Configures a backup peer.  
Modes of Operation  
It is sometimes necessary for DLSw+ and RSRB to coexist in the same network and in the same router  
(for example, during migration from RSRB to DLSw+). Cisco DLSw+ supports this environment. In  
addition, DLSw+ must also interoperate with other vendors’ implementations that are based upon other  
DLSw RFC standards, such as DLSw Version 1 and Version 2.  
Cisco routers, implementing Cisco DLSw+, automatically supports three different modes of operation:  
Dual modeA Cisco router can communicate with some remote peers using RSRB and with others  
using DLSw+, providing a smooth migration path from RSRB to DLSw+; in dual mode, RSRB and  
DLSw+ coexist on the same box; the local peer must be configured for both RSRB and DLSw+; and  
the remote peers must be configured for either RSRB or DLSw, but not both.  
Standards compliance modeDLSw+ can detect automatically (via the DLSw capabilities  
exchange) if the participating router is manufactured by another vendor, therefore operating in  
DLSw standard mode (DLSw Version 1 RFC 1795 and DLSw Version 2 RFC 2166).  
Enhanced modeDLSw+ can detect automatically that the participating router is another DLSw+  
router, therefore operating in enhanced mode, making all of the features of DLSw+ available to the  
SNA and NetBIOS end systems.  
Note  
DLSw+ does not interoperate with the DLSw RFC 1434 standard.  
Some enhanced DLSw+ features are also available when a Cisco router is operating in standards  
compliance mode with another vendor’s router. In particular, enhancements that are locally controlled  
options on a router can be accessed even though the remote router does not have DLSw+. These include  
reachability caching, explorer firewalls and media conversion.  
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Configuring Data-Link Switching Plus  
DLSw+ Configuration Task List  
Network Management  
There are several network management tools available to the user to help them more easily manage and  
troubleshoot their DLSw+ network. CiscoWorks Blue Maps provides a logical view of the portion of  
your router network relevant to DLSw+ (there is a similar tool for RSRB and APPN). CiscoWorks Blue  
SNA View adds to the information provided by Maps by correlating SNA PU and LU names with DLSw+  
circuits and DLSw+ peers. CiscoWorks Blue Internetwork Status Monitor (ISM) support allows you to  
manage your router network from the mainframe console using IBM’s NetView or Sterling’s  
SOLVE:Netmaster. See the DLSw+ Design and Implementation Guide “Using CiscoWorks Blue: Maps,  
SNA View, and Internetwork Status Monitor” chapter for more details.  
Traffic Bandwidth and Queueing Management  
Cisco offers several bandwidth management and queueing features (such as DLSw+ RSVP) to enhance  
the overall performance of your DLSw+ network. The queueing and bandwidth management features are  
described in detail in the DLSw Design and Implementation Guide “Bandwidth Management Queueing”  
chapter.  
Access Control  
DLSw+ offers the following features that allow it to control access to various resources throughout a  
network:  
DLSw+ Ring List or Port List  
DLSw+ ring lists map traffic on specific local rings to remote peers. You can create a ring list of local  
ring numbers and apply the list to remote peer definitions. Traffic received from a remote peer is only  
forwarded to the rings specified in the ring list. Traffic received from a local interface is only forwarded  
to peers if the input ring number appears in the ring list applied to the remote peer definition. The  
definition of a ring list is optional. If you want all peers and all rings to receive all traffic, you do not  
have to define a ring list. Simply specify 0 for the list number in the remote peer statement.  
To define a ring list, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw ring-list list-number rings  
ring-number  
Defines a ring list.  
DLSw+ port lists map traffic on a local interface (either Token Ring or serial) to remote peers. Port lists  
do not work with Ethernet interfaces, or any other interface types connected to DLSw+ by means of a  
bridge group. You can create a port list of local ports and apply the list to remote peer definitions. Traffic  
received from a remote peer is only forwarded to peers if the input port number appears in the port list  
applied to the remote peer definition. The port list command provides a single command to specify both  
serial and Token Ring interfaces. Figure 130 shows how port lists are used to map traffic.  
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DLSw+ Configuration Task List  
Figure 130 Mapping Traffic Using Port Lists  
Token  
Ring  
22  
Explorer  
Token  
Ring  
19  
Token  
Ring  
12  
Peer A  
Peer B  
Port list 2  
Token  
Ring  
15  
Peer C  
Port list 1  
Peer B: Port list 1  
Peer C: Port list 2  
The definition of a port list is optional. If you want all peers and all interfaces to receive all traffic, you  
do not have to define a port list. Simply specify 0 for the list number in the remote peer statement.  
To define a port list, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw port-list list-number type  
number  
Defines a port list.  
Note  
Either the ring list or the port list command can be used to associate rings with a given ring list. The  
ring list command is easier to type in if you have a large number of rings to define.  
DLSw+ Bridge Group List  
DLSw+ bridge group lists map traffic on the local Ethernet bridge group interface to remote peers. You  
can create a bridge group list and apply the list to remote peer definitions. Traffic received from a remote  
peer is only forwarded to the bridge group specified in the bridge group list. Traffic received from a local  
interface is only forwarded to peers if the input bridge group number appears in the bridge group list  
applied to the remote peer definition. The definition of a bridge group list is optional. Because each  
remote peer has a single list number associated with it, if you want traffic to go to a bridge group and to  
either a ring list or port list, you should specify the same list number in each definition  
To define a bridge-group list, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw bgroup-list list-number  
bgroups number  
Defines a ring list.  
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DLSw+ Configuration Task List  
Static Paths  
Static path definitions allow a router to setup circuits without sending explorers. The path specifies the  
peer to use to access a MAC address or NetBIOS name.  
To configure static paths to minimize explorer traffic originating in this peer, use one of the following  
commands in global configuration mode, as needed:  
Command  
Purpose  
Router(config)# dlsw mac-addr mac-addr {ring  
ring number | remote-peer {interface serial  
number | ip-address ip-address} | rif rif string  
| group group}  
Configures the location or path of a static MAC address.  
or  
or  
Router(config)# dlsw netbios-name netbios-name  
{ring ring number | remote-peer {interface  
serial number | ip-address ip-address} | rif rif  
string | group group}  
Configures a static NetBIOS name.  
Static Resources Capabilities Exchange  
To reduce explorer traffic destined for this peer, the peer can send other peers a list of resources for which  
it has information (icanreach) or does not have information (icannotreach). This information is  
exchanged as part of a capabilities exchange.To configure static resources that will be exchanged as part  
of a capabilities exchange, use one of the following commands in global configuration mode, as needed:  
Command  
Purpose  
Router(config)# dlsw icannotreach saps sap  
[sap...]  
Configures a resource not locally reachable by the router.  
or  
or  
Router(config)# dlsw icanreach {mac-exclusive |  
netbios-exclusive | mac-address mac-addr [mask  
mask] | netbios-name name |saps}  
Configures a resource locally reachable by the router.  
Filter Lists in the Remote-Peer Command  
The dest-mac and dmac-output-list options allow you to specify filter lists as part of the dlsw  
remote-peer command to control access to remote peers. For static peers in direct, FST, or TCP  
encapsulation, these filters control which explorers are sent to remote peers. For dynamic peers in TCP  
encapsulation, these filters also control the activation of the dynamic peer. For example, you can specify  
at a branch office that a remote peer is activated only when there is an explorer frame destined for the  
Media Access Control (MAC) address of an FEP.  
The dest-mac option permits the connection to be established only when there is an explorer frame  
destined for the specified MAC address. The dmac-output-list option permits the connection to be  
established only when the explorer frame passes the specified access list. To permit access to a single  
MAC address, use the dest-mac option, because it is a configuration “shortcut” compared to the  
dmac-output-list option.  
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Verifying DLSw+  
Configuring DLSw+ Timers  
To configure DLSw+ timers, use the following command in global configuration mode:  
Command  
Purpose  
Router(config)# dlsw timer  
Configures DLSw+ timers.  
{icannotreach-block-time | netbios-cache-timeout  
| netbios-explorer-timeout | netbios-group-cache  
|netbios-retry-interval |  
netbios-verify-interval |sna-cache-timeout |  
sna-explorer-timeout | sna-group-cache |  
sna-retry-interval | sna-verify-interval} time  
See the DLSw+ Design and Implementation Guide “Customization” chapter and the Cisco IOS Bridging  
and IBM Networking Command Reference (Volume 1 of 2) for command details.  
Verifying DLSw+  
To verify that DLSw+ is configured on the router, use the following command in privileged EXEC mode:  
Command  
Purpose  
Router# show dlsw capabilities local  
Displays the DLSw+ configuration of a specific peer.  
The following sample shows that DLSw+ is configured on router milan:  
milan#show dlsw capabilities local  
DLSw:Capabilities for peer 1.1.1.6(2065)  
vendor id (OUI)  
:'00C' (cisco)  
version number  
:1  
release number  
:0  
init pacing window  
unsupported saps  
num of tcp sessions  
loop prevent support  
:20  
:none  
:1  
:no  
icanreach mac-exclusive :no  
icanreach netbios-excl. :no  
reachable mac addresses :none  
reachable netbios names :none  
cisco version number  
peer group number  
border peer capable  
peer cost  
:1  
:0  
:no  
:3  
biu-segment configured :no  
UDP Unicast support  
local-ack configured  
priority configured  
:yes  
:yes  
:no  
Cisco Internetwork Operating System Software IOS GS Software (GS7-K-M),  
Experimental Version 11.1(10956) [sbales 139]  
Copyright (c) 1986-1996 by cisco Systems, Inc.  
Compiled Thu 30-May-96 09:12 by sbales8  
If only a command prompt appears, then DLSw+ is not configured for the router.  
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Monitoring and Maintaining the DLSw+ Network  
Alternately, to verify that DLSw+ is configured, issue the following command in privileged EXEC  
mode:  
Command  
Purpose  
Router# show running configuration  
Displays the running configuration of a device.  
The global DLSw+ configuration statements, including the dlsw local-peer statement, appear in the  
output before the interface configuration statements. The following sample shows that DLSw+ is  
configured on router milan:  
milan# show run  
version 12.0  
!
hostname Sample  
!
source-bridge ring-group 110  
dlsw local-peer peer-id 10.1.1.1 promiscuous  
!
interface TokenRing0/0  
no ip address  
ring-speed 16  
source-bridge 222 1 110  
source-bridge spanning  
!
Monitoring and Maintaining the DLSw+ Network  
To monitor and maintain activity on the DLSw+ network, use one of the following commands in  
privileged EXEC mode, as needed:  
Command  
Purpose  
Router# show dlsw capabilities interface type  
number  
Displays capabilities of a direct-encapsulated remote peer.  
Router# show dlsw capabilities ip-address  
ip-address  
Displays capabilities of a TCP/FST remote peer.  
Router# show dlsw capabilities local  
Router# show dlsw circuits  
Displays capabilities of the local peer.  
Displays DLSw+ circuit information.  
Router# show dlsw fastcache  
Displays the fast cache for FST and direct-encapsulated peers.  
Router# show dlsw local-circuit  
Displays DLSw+ circuit information when doing local  
conversion.  
Router# show dlsw peers  
Displays DLSw+ peer information.  
Router# show dlsw reachability  
Router# dlsw disable  
Displays DLSw+ reachability information.  
Disables and re-enable DLSw+ without altering the configuration.  
Router# show dlsw statistics [border-peers]  
Displays the number of frames that have been processed in the  
local, remote, and group caches.  
Closes all the DLSw+ circuits1. Also used to reset to zero the  
number of frames that have been processed in the local, remote,  
and group cache.  
Router# clear dlsw circuit  
1. Issuing the clear dlsw circuits command will cause the loss of any associated LLC2 sessions.  
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Configuring Data-Link Switching Plus  
DLSw+ Configuration Examples  
See the DLSw+ Design and Implementation Guide “Using Show and Debug Commands” chapter and the  
Cisco IOS Bridging and IBM Networking Command Reference (Volume 1 of 2) for details of the  
commands.  
DLSw+ Configuration Examples  
The following sections provide DLSw+ configuration examples:  
DLSw+ Using TCP Encapsulation and LLC2 Local Acknowledgment—Basic  
Configuration Example  
This sample configuration requires the following tasks, which are described in earlier sections of this  
document:  
Define a Source-Bridge Ring Group for DLSw+  
Define a DLSw+ Local Peer for the Router  
Define DLSw+ Remote Peers  
Assign DLSw+ to a local data-link control  
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DLSw+ Configuration Examples  
Figure 131 illustrates a DLSw+ configuration with local acknowledgment. Because the RIF is  
terminated, the ring group numbers do not have to be the same.  
Figure 131 DLSw + w ith Local Acknow ledgm ent—Sim ple Configuration  
Ring Group  
10  
Ring Group  
12  
Router A  
10.2.25.1  
Router B  
10.2.5.2  
Token  
Ring  
5
Token  
Ring  
25  
37x5  
3x74  
Router A  
source-bridge ring-group 10  
!
dlsw local-peer peer-id 10.2.25.1  
dlsw remote-peer 0 tcp 10.2.5.2  
interface loopback 0  
ip address 10.2.25.1 255.255.255.0  
!
interface tokenring 0  
no ip address  
ring-speed 16  
source-bridge 25 1 10  
source-bridge spanning  
Router B  
source-bridge ring-group 12  
dlsw local-peer peer-id 10.2.5.2  
dlsw remote-peer 0 tcp 10.2.25.1  
interface loopback 0  
ip address 10.2.5.2 255.255.255.0  
!
interface tokenring 0  
no ip address  
ring-speed 16  
source-bridge 5 1 12  
source-bridge spanning  
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Configuring Data-Link Switching Plus  
DLSw+ Configuration Examples  
DLSw+ Using TCP Encapsulation with Local Acknowledgment—Peer Group  
Configuration Example 1  
Figure 132 illustrates border peers with TCP encapsulation. Router A is configured to operate in  
promiscuous mode, and border peers Routers B and C forward broadcasts. This configuration reduces  
processing requirements in Router A (the access router) and still supports any-to-any networks.  
Configure Border peer B and C so that they peer to each other.  
Figure 132 DLSw + w ith Peer Groups Specified (Exam ple 1)  
Token  
Ring  
3
Router A  
Router C  
Router B  
s0  
Token  
Ring  
200  
Token  
Ring  
33  
t0  
t3/1  
t0  
IP cloud  
t3/0  
s0  
128.207.152.5  
128.207.150.8  
border  
128.207.169.3  
border  
NetBIOS  
server  
NetBIOS  
requester  
Group 70  
Group 69  
Router A  
hostname Router A  
!
source-bridge ring group 31  
dlsw local-peer peer-id 128.207.152.5 group 70 promiscuous  
dlsw remote peer 0 tcp 128.207.150.8  
interface loopback 0  
ip address 128.207.152.5 255.255.255.0  
!
interface serial 0  
ip unnumbered tokenring  
clockrate 56000  
!
interface tokenring 0  
ip address 128.207.152.5 255.255.255.0  
ring-speed 16  
source-bridge 200 13 31  
source-bridge spanning  
!
router igrp 777  
network 128.207.0.0  
Router B  
hostname Router B  
!
source-bridge ring-group 31  
dlsw local-peer peer-id 128.207.150.8 group 70 border promiscuous  
dlsw remote-peer 0 tcp 128.207.169.3  
interface loopback 0  
ip address 128.207.150.8 255.255.255.0  
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Configuring Data-Link Switching Plus  
DLSw+ Configuration Examples  
!
interface serial 0  
ip unnumbered tokenring 0  
bandwidth 56  
!
interface tokenring 0  
ip address 128.207.150.8 255.255.255.0  
ring-speed 16  
source-bridge 3 14 31  
source-bridge spanning  
!
router igrp 777  
network 128.207.0.0  
Router C  
hostname Router C  
!
source-bridge ring-group 69  
dlsw local-peer peer-id 128.207.169.3 group 69 border promiscuous  
dlsw remote-peer 0 tcp 128.207.150.8  
interface loopback 0  
ip address 128.207.169.3 255.255.255.0  
!
interface tokenring 3/0  
description fixed to flashnet  
ip address 128.207.2.152 255.255.255.0  
ring-speed 16  
multiring all  
!
interface tokenring 3/1  
ip address 128.207.169.3 255.255.255.0  
ring-speed 16  
source-bridge 33 2 69  
source-bridge spanning  
!
router igrp 777  
network 128.207.0.0  
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Configuring Data-Link Switching Plus  
DLSw+ Configuration Examples  
DLSw+ Using TCP Encapsulation with Local Acknowledgment—Peer Group  
Configuration Example 2  
Figure 133 illustrates a peer group configuration that allows any-to-any connection except for Router B.  
Router B has no connectivity to anything except router C because the promiscuous keyword is omitted.  
Figure 133 DLSw + w ith Peer Groups Specified (Exam ple 2)  
Token  
Token  
Ring  
Ring  
93  
92  
Token  
Ring  
96  
Token  
Ring  
500  
Router C  
T0  
Mainframe  
S0  
FEP  
150.150.100.1  
S9  
Router A  
T0/1  
T0/2  
T0/0  
S1/0  
150.150.99.1  
150.150.96.1  
S7  
S8  
Router D  
S1/1  
Token  
Ring  
99  
Router B  
150.150.98.1  
S0  
S1  
S0  
150.150.97.1  
SDLC “01”  
controller  
T0  
Router E  
T0  
Token  
Ring  
98  
Token  
Ring  
97  
Group 2  
Group 1  
Router A  
hostname Router A  
!
source-bridge ring-group 2000  
dlsw local-peer peer-id 150.150.99.1 group 2 promiscuous  
dlsw remote-peer 0 tcp 150.150.100.1  
!
interface loopback 0  
ip address 150.150.99.1 255.255.255.192  
!
interface tokenring 0  
no ip address  
ring-speed 16  
source-bridge 99 1 2000  
source-bridge spanning  
!
router eigrp 202  
network 150.150.0.0  
Router B  
hostname Router B  
!
source-bridge ring-group 2000  
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DLSw+ Configuration Examples  
dlsw local-peer peer-id 150.150.98.1 group 2  
dlsw remote-peer 0 tcp 150.150.100.1  
!
interface loopback 0  
ip address 150.150.98.1 255.255.255.192  
!
interface serial 1  
no ip address  
encapsulation sdlc  
no keepalive  
clockrate 9600  
sdlc role primary  
sdlc vmac 4000.8888.0100  
sdlc address 01  
sdlc xid 01 05d20006  
sdlc partner 4000.1020.1000 01  
sdlc dlsw 1  
!
interface tokenring 0  
no ip address  
ring-speed 16  
source-bridge 98 1 2000  
source-bridge spanning  
!
router eigrp 202  
network 150.150.0.0  
Router C  
hostname Router C  
!
source-bridge ring-group 2000  
dlsw local-peer peer-id 150.150.100.1 group 2 border promiscuous  
dlsw remote-peer 0 tcp 150.150.96.1  
!
interface loopback 0  
ip address 150.150.100.1 255.255.255.192  
interface tokenring 0  
no ip address  
ring-speed 16  
source-bridge 500 1 2000  
source-bridge spanning  
!
router eigrp 202  
network 150.150.0.0  
Router D  
hostname Router D  
!
source-bridge ring-group 2000  
dlsw local-peer peer-id 150.150.96.1 group 1 border promiscuous  
dlsw remote-peer 0 tcp 150.150.100.1  
!
interface loopback 0  
ip address 150.150.96.1 255.255.255.192  
!
interface tokenring 0/0  
no ip address  
ring-speed 16  
source-bridge 96 1 2000  
source-bridge spanning  
!
interface tokenring 0/1  
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DLSw+ Configuration Examples  
no ip address  
ring-speed 16  
source-bridge 92 1 2000  
source-bridge spanning  
!
.interface tokenring 0/2  
no ip address  
ring-speed 16  
source-bridge 93 1 2000  
source-bridge spanning  
!
router eigrp 202  
network 150.150.0.0  
Router E  
hostname Router E  
!
source-bridge ring-group 2000  
dlsw local-peer peer-id 150.150.97.1 group 1 promiscuous  
dlsw remote-peer 0 tcp 150.150.96.1  
!
interface loopback 0  
ip address 150.150.97.1 255.255.255.192  
!
interface tokenring 0  
no ip address  
ring-speed 16  
source-bridge 97 1 2000  
source-bridge spanning  
!
router eigrp 202  
network 150.150.0.0  
DLSw+ with SDLC Multidrop Support Configuration Examples  
In the following example, all devices are type PU 2.0:  
interface serial 2  
mtu 4400  
no ip address  
encapsulation sdlc  
no keepalive  
clockrate 19200  
sdlc role primary  
sdlc vmac 4000.1234.5600  
sdlc address C1  
sdlc xid C1 05DCCCC1  
sdlc partner 4001.3745.1088 C1  
sdlc address C2  
sdlc xid C2 05DCCCC2  
sdlc partner 4001.3745.1088 C2  
sdlc dlsw C1 C2  
The following example shows mixed PU 2.0 (device using address C1) and PU 2.1 (device using address  
C2) devices:  
interface serial 2  
mtu 4400  
no ip address  
encapsulation sdlc  
no keepalive  
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DLSw+ Configuration Examples  
clockrate 19200  
sdlc role primary  
sdlc vmac 4000.1234.5600  
sdlc address C1  
sdlc xid C1 05DCCCC1  
sdlc partner 4001.3745.1088 C1  
sdlc address C2 xid-poll  
sdlc partner 4001.3745.1088 C2  
sdlc dlsw C1 C2  
In the following example, all devices are type PU 2.1 (Method 1):  
interface serial 2  
mtu 4400  
no ip address  
encapsulation sdlc  
no keepalive  
clockrate 19200  
sdlc role primary  
sdlc vmac 4000.1234.5600  
sdlc address C1 xid-poll  
sdlc partner 4001.3745.1088 C1  
sdlc address C2 xid-poll  
sdlc partner 4001.3745.1088 C2  
sdlc dlsw C1 C2  
In the following example, all devices are type PU 2.1 (Method 2):  
interface serial 2  
mtu 4400  
no ip address  
encapsulation sdlc  
no keepalive  
clockrate 19200  
sdlc role prim-xid-poll  
sdlc vmac 4000.1234.5600  
sdlc address C1  
sdlc partner 4001.3745.1088 C1  
sdlc address C2  
sdlc partner 4001.3745.1088 C2  
sdlc dlsw C1 C2  
DLSw+ with LLC2-to-SDLC Conversion Between PU 4-to-PU 4 Communication  
Example  
The following example is a sample configuration for LLC2-to-SDLC conversion for PU 4-to-PU 4  
communication as shown in Figure 134:  
Figure 134 LLC2-to-SDLC Conversion for PU 4-to-PU 4 Com m unication  
Token  
Frame Relay  
Ring  
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Configuring Data-Link Switching Plus  
DLSw+ Configuration Examples  
Router A  
source-bridge ring-group 1111  
dlsw local-peer peer-id 10.2.2.2  
dlsw remote-peer 0 tcp 10.1.1.1  
interface loopback 0  
ip address 10.2.2.2 255.255.255.0  
interface TokenRing 0  
no ip address  
ring-speed 16  
source-bridge 2 1111  
source-bridge spanning  
Router B  
dlsw local-peer peer-id 10.1.1.1  
dlsw remote-peer 0 tcp 10.2.2.2  
interface loopback 0  
ip address 10.1.1.1 255.255.255.0  
interface serial 0  
mtu 4096  
no ip address  
encapsulation sdlc  
no keepalive  
nzri-encoding  
clockrate 9600  
sdlc vmac 4000.3745.0000  
sdlc N1 48016  
sdlc address 04 echo  
sdlc partner 4000.1111.0020 04  
sdlc dlsw 4  
DLSw+ Translation Between Ethernet and Token Ring Configuration Example  
DLSw+ also supports Ethernet media. The configuration is similar to other DLSw+ configurations,  
except for configuring for a specific media. The following example shows Ethernet media (see  
Figure 135 DLSw + Translation Between Ethernet and Token Ring  
Router B  
Router A  
e0  
e1/2  
128.207.1.145  
128.207.111.1  
Token  
Ring  
7
AS/400  
Router A  
hostname Router A  
!
dlsw local-peer peer-id 128.207.111.1  
dlsw remote-peer 0 tcp 128.207.1.145  
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DLSw+ Configuration Examples  
dlsw bridge-group 5  
!
interface loopback 0  
ip address 128.207.111.1 255.255.255.0  
interface Ethernet 0  
no ip address  
bridge-group 5  
!
bridge 5 protocol ieee  
Router B  
hostname Router B  
!
source-bridge transparent 500 1000 1 5  
dlsw local-peer peer-id 128.207.1.145  
dlsw remote-peer 0 tcp 128.207.111.1  
dlsw bridge-group 5  
!
interface loopback 0  
ip address 128.207.1.145 255.255.255.0  
interface ethernet 1/2  
no ip address  
bridge-group 5  
!
interface tokenring 2/0  
no ip address  
ring-speed 16  
source-bridge 7 1 500  
source-bridge spanning  
!
bridge 5 protocol ieee  
Because DLSw+ does not do local translation between different LAN types, Router B must be  
configured for SR/TLB by issuing the source-bridge transparent command. Also, note that the bridge  
groups are configured on the ethernet interfaces.  
DLSw+ Translation Between FDDI and Token Ring Configuration Example  
DLSw+ also supports FDDI media. The configuration is similar to other DLSw+ configurations except  
for configuring for a specific media type. The following example shows FDDI media (see Figure 136).  
Figure 136 DLSw + Translation Between FDDI and Token Ring  
Token  
Ring  
DLSw+  
FDDI  
Router A  
Router B  
In the following configuration, an FDDI ring on Router A is connected to a Token Ring on Router B  
across a DLSw+ link.  
Router A  
source-bridge ring-group 10  
dlsw local-peer peer-id 132.11.11.2  
dlsw remote-peer 0 tcp 132.11.11.3  
interface loopback 0  
ip address 132.11.11.2 255.255.255.0  
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DLSw+ Configuration Examples  
interface fddi 0  
no ip address  
source-bridge 26 1 10  
source-bridge spanning  
Router B  
source-bridge ring-group 10  
dlsw local peer peer-id 132.11.11.3  
dlsw remote-peer 0 tcp 132.11.11.2  
interface loopback 0  
ip address 132.11.11.3 255.255.255.0  
interface tokenring 0  
no ip address  
source-bridge 25 1 10  
source-bridge spanning  
DLSw+ Translation Between SDLC and Token Ring Media Example  
DLSw+ provides media conversion between local or remote LANs and SDLC. For additional  
information about configuring SDLC parameters, refer to the chapter “Configuring LLC2 and SDLC  
Parameters.”  
Figure 137 illustrates DLSw+ with SDLC encapsulation. For this example, 4000.1020.1000 is the MAC  
address of the FEP host (PU 4.0). The MAC address of the AS/400 host is 1000.5aed.1f53, which is  
defined as Node Type 2.1. Router B serves as the primary station for the remote secondary station 01.  
Router B can serve as either primary station or secondary station to remote station D2.  
Figure 137 DLSw + Translation Between SDLC and Token Ring Media  
1000.5aed.1F53  
AS/400  
Token  
Ring  
500  
Token  
Ring  
400  
FEP  
4000.1020.1000  
Router B  
S0  
S8  
Token  
Ring  
100  
S2 S1  
Router A  
PU type 2.1  
sdlc address  
D2  
PU type 2.0  
sdlc address  
01  
Router A  
hostname Router A  
!
source-bridge ring-group 2000  
dlsw local-peer peer-id 150.150.10.2  
dlsw remote-peer 0 tcp 150.150.10.1  
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DLSw+ Configuration Examples  
!
interface loopback 0  
ip address 150.150.10.2 255.255.255.0  
interface serial 8  
ip address 150.150.11.2 255.255.255.192  
clockrate 56000  
!
interface tokenring 0  
no ip address  
ring-speed 16  
source-bridge 500 1 2000  
source-bridge spanning  
!
router eigrp 202  
network 150.150.0.0  
Router B  
hostname Router B  
!
source-bridge ring-group 2000  
dlsw local-peer peer-id 150.150.10.1  
dlsw remote-peer 0 tcp 150.150.10.2  
!
interface loopback 0  
ip address 150.150.10.1 255.255.255.0  
interface serial 0  
ip address 150.150.11.1 255.255.255.192  
!
interface serial 1  
description PU2 with SDLC station role set to secondary  
no ip address  
encapsulation sdlc  
no keepalive  
clockrate 9600  
sdlc role primary  
sdlc vmac 4000.9999.0100  
sdlc address 01  
sdlc xid 01 05d20006  
sdlc partner 4000.1020.1000 01  
sdlc dlsw 1  
!
interface serial 2  
description Node Type 2.1 with SDLC station role set to negotiable or primary  
encapsulation sdlc  
sdlc role prim-xid-poll  
sdlc vmac 1234.3174.0000  
sdlc address d2  
sdlc partner 1000.5aed.1f53 d2  
sdlc dlsw d2  
!
interface tokenring 0  
no ip address  
ring-speed 16  
source-bridge 100 1 2000  
source-bridge spanning  
!
interface tokenring 1  
no ip address  
ring-speed 16  
source-bridge 400 1 2000  
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DLSw+ Configuration Examples  
source-bridge spanning  
!
router eigrp 202  
network 150.150.0.0  
DLSw+ over Frame Relay Configuration Example  
Frame Relay support extends the DLSw+ capabilities to include Frame Relay in direct mode. Frame  
Relay support includes permanent virtual circuit capability. DLSw+ runs over Frame Relay with or  
without local acknowledgement. It supports the Token Ring-to-Token Ring connections similar to FST  
and other direct data link controls. Figure 138 illustrates a DLSw+ configuration over Frame Relay with  
RIF Passthrough.  
Figure 138 DLSw + over Fram e Relay  
Router A  
Router B  
End station  
End station  
Frame Relay  
Network  
Token  
Ring  
Token  
Ring  
Frame Relay  
Session  
Direct Session  
The following configuration examples are based on Figure 139. The Token Rings in the illustration are  
in Ring 2.  
Router A  
source-bridge ring-group 100  
dlsw local-peer 10.2.23.1  
dlsw remote-peer 0 frame-relay interface serial 0 30 passthru  
interface loopback 0  
ip address 10.2.23.1 255.255.255.0  
interface tokenring 0  
ring-speed 16  
source-bridge spanning 1 1 100  
!
interface serial 0  
mtu 3000  
no ip address  
encapsulation frame-relay  
frame-relay lmi-type ansi  
frame-relay map dlsw 30  
Router B  
source-bridge ring-group 100  
dlsw local-peer 10.2.23.2  
dlsw remote-peer 0 frame-relay interface serial 0 30 passthru  
interface loopback 0  
ip address 10.2.23.2 255.255.255.0  
interface tokenring 0  
ring-speed 16  
source-bridge spanning 2 1 100  
!
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DLSw+ Configuration Examples  
interface serial 0  
mtu 3000  
no ip address  
encapsulation frame-relay  
frame-relay lmi-type ansi  
frame-relay map dlsw 30  
DLSw+ over QLLC Configuration Examples  
The following three examples describe QLLC support for DLSw+.  
Example 1  
In this configuration, DLSw+ is used to allow remote devices to connect to a DLSw+ network over an  
X.25 public packet-switched network.  
In this example, all QLLC traffic is addressed to destination address 4000.1161.1234, which is the MAC  
address of the FEP.  
The remote X.25-attached IBM 3174 cluster controller is given a virtual MAC address of  
1000.0000.0001. This virtual MAC address is mapped to the X.121 address of the 3174 (31104150101)  
in the X.25 attached router.  
interface serial 0  
encapsulation x25  
x25 address 3110212011  
x25 map qllc 1000.0000.0001 31104150101  
qllc dlsw partner 4000.1611.1234  
Example 2  
In this configuration, a single IBM 3174 cluster controller needs to communicate with both an AS/400  
and a FEP. The FEP is associated with subaddress 150101 and the AS/400 is associated with subaddress  
151102.  
If an X.25 call comes in for 33204150101, the call is mapped to the FEP and forwarded to MAC address  
4000.1161.1234. The IBM 3174 appears to the FEP as a Token Ring-attached resource with MAC  
address 1000.0000.0001. The IBM 3174 uses a source SAP of 04 when communicating with the FEP,  
and a source SAP of 08 when communicating with the AS/400.  
interface serial 0  
encapsulation x25  
x25 address 31102  
x25 map qllc 1000.0000.0001 33204  
qllc dlsw subaddress 150101 partner 4000.1161.1234  
qllc dlsw subaddress 150102 partner 4000.2034.5678 sap 04 08  
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Example 3  
In this example, two different X.25 resources want to communicate over X.25 to the same FEP.  
In the router attached to the X.25 network, every X.25 connection request for X.121 address  
31102150101 is directed to DLSw+. The first SVC to be established will be mapped to virtual MAC  
address 1000.0000.0001. The second SVC to be established will be mapped to virtual MAC address  
1000.0000.0002.  
interface serial 0  
encapsulation x25  
x25 address 31102  
x25 map qllc 33204  
x25 map qllc 35765  
qllc dlsw subaddress 150101 vmacaddr 1000.0000.0001 2 partner 4000.1611.1234  
DLSw+ with RIF Passthrough Configuration Example  
Figure 139 is a sample configuration for DLSw+ using the RIF Passthrough feature.  
Figure 139 Network Configuration w ith RIF Passthrough  
VR  
VR  
100  
100  
A 10.1.12.1  
B 10.1.14.2  
TCP/IP  
25  
51  
3745  
3745  
Router A  
source-bridge ring-group 100  
dlsw local-peer peer id 10.1.12.1  
dlsw remote-peer 0 tcp 10.1.14.2 rif-passthru 100  
interface loopback 0  
ip address 10.1.12.1 255.255.255.0  
interface tokenring 0  
ring-speed 16  
source-bridge 25 1 100  
source-bridge spanning  
Router B  
source-bridge ring-group 100  
dlsw local-peer peer id 10.1.14.2  
dlsw remote-peer 0 tcp 10.1.12.1 rif-passthru 100  
interface loopback 0  
ip address 10.1.14.2 255.255.255.0  
interface tokenring 0  
ring-speed 16  
source-bridge 51 1 100  
source-bridge spanning  
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DLSw+ Configuration Examples  
DLSw+ with Enhanced Load Balancing Configuration Example  
Figure 140 shows DLSw+ with the Enhanced Load Balancing feature.  
Figure 140 DLSw + w ith Enhanced Load Balancing  
Token  
Ring  
RTR B  
Token  
Ring  
Token  
Ring  
RTR A  
RTR C  
RTR D  
Router A is configured for the DLSw+ Enhanced Load Balancing feature to load balance traffic among  
the DLSw+ remote peers B, C, and D.  
Router A  
dlsw local-peer 10.2.19.1  
dlsw remote-peer 0 tcp 10.2 24.2 circuit-weight 10  
dlsw remote-peer 0 tcp 10.2.19.5 circuit-weight 6  
dlsw remote-peer 0 tcp 10.2.20.1 circuit-weight 20  
dlsw load-balance circuit-count  
dlsw timer explorer-wait-time 100  
Router B  
dlsw local-peer 10.2.24.2 cost 1 promiscuous  
Router C  
dlsw local-peer 10.2.19.5 cost 1 promiscuous  
Router D  
dlsw local-peer 10.2.20.1 cost 1 promiscuous  
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DLSw+ Configuration Examples  
DLSw+ Peer Cluster Feature Configuration Example  
Figure 141 shows a DLSw+ network configured with the DLSw+ Peer Clusters feature.  
Figure 141 DLSw + Peer Cluster Feature  
X
Peer cluster  
ID 5  
MPA  
MPB  
Token  
Ring  
BP1  
BP2  
Y
Peer group 1  
Peer group 2  
Because BP2 is configured as the border peer with the DLSw+ Peer Clusters feature, it does not forward  
explorers to both MPA and MPB since they are part of the same peer cluster.  
BP2  
source-bridge ring-group 310  
dlsw local-peer 10.1.1.3 border group 2 promiscuous  
MPA  
source-bridge ring-group 310  
dlsw local-peer 10.1.1.1 group 2 promiscuous cluster 5  
dlsw remote-peer 0 tcp 10.1.1.3  
MPB  
source-bridge ring-group 310  
dlsw local-peer 10.1.1.2 group 2 promiscuous cluster 5  
dlsw remote-peer tcp 0 10.1.1.3  
MPC  
dlsw local-peer 10.1.1.4 group 2 promiscuous  
dlsw remote-peer tcp 0 10.1.1.3  
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DLSw+ Configuration Examples  
DLSW+ RSVP Bandwidth Reservation Feature Configuration Example  
Figure 142 shows a DLSw+ network with the DLSw+ RSVP Bandwidth Reservation feature configured.  
Figure 142 DLSw + RSVP Bandw idth Reservation Feature Configured  
DLSW RTR 1  
IP RTR 1  
IP RTR 2  
DLSW RTR 2  
10.2.24.3  
Token  
Ring  
10.2.17.1  
10.1.15.2  
10.1.16.2  
Workstation 1  
Workstation 2  
Workstation 3  
Workstation 4  
DLSWRTR 1 and DLSWRTR 2 are configured for the DLSw+ RSVP Bandwidth Reservation feature  
with an average bit rate of 40 and a maximum-burst rate of 10.  
DLSWRTR 1  
dlsw local-peer peer id 10.2.17.1  
dlsw remote-peer 0 tcp 10.2.24.3  
dlsw rsvp 40 10  
DLSWRTR2  
dlsw local-peer peer id 10.2.24.3  
dlsw remote-peer 0 tcp 10.2.17.1  
dlsw rsvp 40 10  
The following output of the show ip rsvp sender command on the DLSWRTR2 verifies that PATH  
messages are being sent from DLSWRTR2:  
DLSWRTR2#show ip rsvp sender  
To  
10.2.17.1 10.2.24.3 TCP 2065 11003  
10.2.24.3 10.2.17.1 TCP 11003 2065 10.2.17.1 Et1/1 10K  
From  
Pro DPort Sport Prev Hop I/F BPS  
Bytes  
28K  
28K  
10K  
The following output of the show ip rsvp req command on the DLSWRTR2 verifies that RESV  
messages are being sent from DLSWRTR2:  
DLSWRTR2#show ip rsvp req  
To  
From  
10.2.17.1  
Pro DPort Sport Next Hop  
TCP 11003 2065 10.2.17.1  
I/F  
Fi Serv BPS Bytes  
28K  
10.2.24.3  
Et1/1 FF RATE 10K  
If the IP cloud is able to guarantee the bandwidth requested and the show ip rsvp sender and show ip  
rsvp req commands are successful, issue the show ip rsvp res command to verify that a reservation was  
made from DLSWRTR1 to DLSWRTR2:  
DLSWRTR2#show ip rsvp rese  
To  
From  
10.2.24.3 TCP 2065 11003 10.2.17.1 Et1/1 FF RATE  
10.2.17.1 TCP 11003 2065 FF RATE  
Pro DPort Sport Next Hop  
I/F  
Fi Serv BPS Bytes  
10.2.17.1  
10.2.24.3  
10K  
10K  
28K  
28K  
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DLSw+ Configuration Examples  
DLSw+ RSVP Bandwidth Reservation Feature with Border Peers Configuration  
Example  
Figure 143 shows a DLSw+ border peer network configured with DLSw+ RSVP.  
Figure 143 DLSw + RSVP Bandw idth Reservation Feature in a Border Peer Network  
DLSW RTR 1  
IP RTR 1  
IP RTR 2  
DLSW RTR 2  
Token  
Ring  
Token  
Ring  
10.2.17.1  
10.3.15.2  
10.3.16.2  
10.14.25.2  
Workstation 1  
Workstation 2  
Group 1  
Group 2  
The following example configures DLSWRTR1 to send PATH messages at rates of 40 kbps and 10 kbps  
and DLSWRTR2 to send PATH messages at rates of 10.  
DLSWRTR1  
dlsw local-peer peer-id 10.2.17.1 group 1 promiscuous  
dlsw rsvp default  
dlsw remote-peer 0 tcp 10.3.15.2  
dlsw peer-on-demand-defaults rsvp 40 10  
IPRTR1  
dlsw local-peer peer-id 10.3.15.2 group 1 border promiscuous  
dlsw remote-peer 0 tcp 10.3.16.2  
IPRTR2  
dlsw local-peer peer-id 10.3.16.2 group 2 border promiscuous  
dlsw remote-peer 0 tcp 10.3.15.2  
DLSWRTR2  
dlsw local-peer peer-id 10.14.25.2 group 2 promiscuous  
dlsw rsvp default  
dlsw remote-peer 0 tcp 10.3.16.2  
The following output of the show ip rsvp sender command on DLSWRTR2 verifies that PATH messages  
are being sent from DLSWRTR2:  
DLSWRT2#show ip rsvp sender  
To  
From  
10.14.25.2  
10.2.17.1  
Pro DPort Sport Prev Hop  
TCP 2065 11003  
TCP 11003 2065 10.2.17.1  
I/F BPS Bytes  
10.2.17.1  
10.14.25.2  
10K  
28K  
28K  
Et1/1 10K  
The following output of the show ip rsvp request command on DLSWRTR2 verifies that RESV  
messages are being sent from DLSWRTR 2:  
DLSWRT2#show ip rsvp req  
To  
From  
10.2.17.1  
Pro DPort Sport Next Hop  
TCP 11003 2065 10.2.17.1  
I/F  
Fi Serv BPS Bytes  
28K  
10.14.25.2  
Et1/1 FF RATE 10K  
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DLSw+ Configuration Examples  
The following output of the show ip rsvp res command on the DLSWRTR1 verifies that the RSVP  
reservation was successful:  
DLSWRTR1#show ip rsvp rese  
To  
From  
10.14.25.2  
10.2.17.1  
Pro DPort Sport Next Hop  
TCP 2065 11003 10.14.25.2  
TCP 11003 2065  
I/F  
Fi Serv BPS Bytes  
10.2.17.1  
10.14.25.2  
Et1/1 FF RATE 10K  
FF RATE 10K  
28K  
28K  
DLSw+ with Ethernet Redundancy Configuration Example  
Figure 144 shows that Router A, Router B, and Router C advertise their presence on the Ethernet via  
their Ethernet interfaces to the multicast MAC address 9999.9999.9999. Because Router B is the master  
router, it keeps a database of all circuits handled within the domain and grants or denies permission for  
new circuit requests for Router A and Router C. There is no special configuration required for the end  
stations or for the remote peer. Only the DLSw+ devices on the LAN need the extra configuration.  
Master Router B waits 1.5 seconds after it receives the first IWANTIT primitive before assigning the new  
SNA circuit to one of its ethernet redundancy peers because of the dlsw transparent timers sna 1500  
command.  
Figure 144 DLSw + w ith Ethernet Redundancy  
Workstation X  
Router A  
Router B  
Router C  
Router D  
Router A  
dlsw local-peer peer id 10.2.24.2  
dlsw remote-peer 0 tcp 10.2.17.1  
interface loopback 0  
ip address 10.2.24.2 255.255.255.0  
int e1  
ip address 150.150.2.1 255.255.255.0  
dlsw transparent redundancy-enable 9999.9999.9999  
Router B  
dlsw local-peer peer-id 10.2.24.3  
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DLSw+ Configuration Examples  
dlsw remote-peer 0 tcp 10.1.17.1  
interface loopback 0  
ip address 10.2.24.3 255.255.255.0  
int e1  
ip address 150.150.2.2 255.255.255.0  
dlsw transparent redundancy-enable 9999.9999.9999 master priority 1  
dlsw transparent timers sna 1500  
Router C  
dlsw local-peer peer-id 10.2.24.4  
dlsw remote-peer 0 tcp 10.2.17.1  
interface loopback 0  
ip address 10.2.24.4 255.255.255.0  
int e1  
ip address 150.150.2.3 255.255.255.0  
dlsw transparent redundancy-enable 9999.9999.9999  
Router D  
dlsw local-peer peer-id 10.2.17.1 promiscuous  
DLSw+ with Ethernet Redundancy Enabled for Switch Support Configuration  
Example  
Figure 145 is a sample configuration of the DLSw+ Ethernet Redundancy feature in a switched  
environment. The ethernet switch sees the device with MAC address 4000.0010.0001 one port at a time  
because Router A and Router B have mapped different MAC addresses to it. This configuration is known  
as MAC-address mapping. Router A is configured so that MAC address 4000.0001.0000 maps to the  
actual device with MAC address 4000.0010.0001. Router B is configured so that MAC address  
4000.0201.0001 maps to the actual device with MAC address 4000.0010.0001. Router A and B backup  
one another. Router A is configured as the master with a default priority of 100. Master Router A waits  
1.5 seconds after it receives the first IWANTIT primitive before assigning the new SNA circuit to one of  
its ethernet redundancy peers because of the dlsw transparent timers sna 1500 command.  
Figure 145 DLSw + w ith Ethernet Redundancy in a Sw itched Environm ent  
Workstation Z  
Router A  
Router B  
Workstation X  
Workstation Y  
4000.0010.0001  
Ethernet switch  
Cisco IOS Bridging and IBM Networking Configuration Guide  
78-11737-02  
BC-3 3 2  
 
   
Configuring Data-Link Switching Plus  
DLSw+ Configuration Examples  
Router A  
dlsw local peer peer-id 10.2.17.1  
dlsw remote-peer 0 tcp 10.3.2.1  
dlsw transparent switch-support  
interface loopback 0  
ip address 10.2.17.1 255.255.255.0  
int e 0  
mac-address 4000.0000.0001  
ip address 150.150.2.1 255.255.255.0  
dlsw transparent redundancy-enable 9999.9999.9999 master-priority  
dlsw transparent map local-mac 4000.0001.0000 remote-mac 4000.0010.0001  
neighbor 4000.0000.0011  
dlsw transparent timers sna 1500  
Router B  
dlsw local peer peer-id 10.2.17.2  
dlsw remote-peer 0 tcp 10.3.2.1  
dlsw transport switch-support  
interface loopback 0  
ip address 10.2.17.2 255.255.255.0  
int e 1  
mac-address 4000.0000.0011  
ip address 150.150.3.1 255.255.255.0  
dlsw transparent redundancy-enable 9999.9999.9999  
dlsw transparent map local-mac 4000.0201.0001 remote-mac 4000.0010.0001  
neighbor 4000.0000.0001  
Cisco IOS Bridging and IBM Networking Configuration Guide  
78-11737-02  
BC-3 3 3  
 
Configuring Data-Link Switching Plus  
DLSw+ Configuration Examples  
Cisco IOS Bridging and IBM Networking Configuration Guide  
78-11737-02  
BC-3 3 4  
 

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