3600 dlsw peer group clusters

8/14/2019 3600 DLSw Peer Group Clusters

1/14

DLSw+ Peer Group Clusters 1

DLSw+ Peer Group Clusters

Feature SummaryIn a large DLSw+ network with heavily populated branches sessions are sometimes dropped and

performance is impacted because a DLSw+ router does not have enough memory and processing

resources to relay all circuits between the branches and the data center. This problem is typicallyfixed by placing routers in the data center and peering a set of branch routers to each of them,

creating a border peer design (Figure 1).

Figure 1 Typical Large DLSw+ Network

If, however, more than one router is connected to the same LAN within the same peer group to

circumvent overloading one router (for example, member peer A MPA and member peer B

MPB), then theexplorersareduplicated when theborder peer forwards an explorer within its Peer

Group. In Figure 1, BP2 forwards the explorer to all the routers in Peer Group 2 (including MPA and

BP2

MPA

MPB

BP1

Peer group 1 Peer group 2

17267

TokenRing

TokenRing

TokenRing


2/14

Feature Summary

2 Cisco IOS Release 12.0(3)T

RAF

MPB even though they are serving the same LAN.) The DLSw+ Peer Clusters feature avoids these

explorer replications and resolves some circuit connectivity issues that are the result of the explorer

replication.

BenefitsThe DLSw+ Peer Clusters feature reduces explorer replication that typically occurs in a large

DLSw+ peer group design where there are multiple routers connected to the same LAN (Figure 2).

Figure 2 DLSw+ with the DLSw+ Peer Clusters Feature Configured

In Figure 2, MPA and MPB are serving the same Token Ring LAN to share the circuit load between

the branches (for example, workstations X through Y) and the data center (BP2). The problem arises

when workstation X wants to communicate with workstation Y because the explorer is sent three

times on the LAN. The explorer, which originated from MPA, follows these paths:

X>MPA>BP2>MPB, all other MPs in Peer Group 2, BP1>Y,

X>MPB>BP2>MPA>Y

X>Y

The border peer will not forward an explorer back to the peer from which it originated. For example,

the X packet will not travel X> MPA>BP>MPA>Y. Although Peer Group Caching (a

feature implemented in Cisco IOS 11.3) lessens the impact beyond the first explorer, there is stilladditional load on the internetwork that affects performance, bandwidth and CPU memory.

The DLSw+ Peer Clusters feature clusters DLSw+ peers (that are connected to the same LAN)

into logical groups. Once the multiple peers are defined in the same peer group cluster, the DLSw+

border peer recognizes that it does not have to forward explorers to more than one member within

the same peer group cluster.

BP2

Peer cluster

ID 5

MPA

X

Y

MPB

BP1

Peer group 1 Peer group 2 17268

TokenRing


3/14


4/14

Configuration Tasks


RAF

Configuration TasksThe 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-idof a particular peer is

defined in either the border peer or on the member peer, but not both because of potential

configuration confusion.

Enable DLSw+ Peer Clusters on Local RouterWhen 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.

To enable the DLSw+ Peer Clusters feature on the member peer, use the following command in

global configuration mode:

Enable DLSw+ Peer Clusters on the Border PeerWhen the user configures the cluster option in the dlsw remote-peer command on a border peer,

they 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

dlsw local-peer [cluster cluster-id] Defines the Member Peer as partof a

particular cluster and enables the

DLSw+ Peer Clusters feature

locally.

Command Purpose

dlsw remote-peer tcp [cluster cluster-id] Defines the border peer router as

part of a particular cluster and

enables the DLSw+ Peer Clusters

feature.This feature is used only for

the configuration of a border peer.


5/14

Enable DLSw+ Peer Clusters on the Border Peer


Configuration ExamplesFigure 3shows a DLSw+ network configured with the DLSw+ Peer Clusters feature.

Figure 3 DLSw+ with the DLSw+ Peer Clusters Feature

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.

BP2source-bridge ring-group 310

dlsw local-peer 10.1.1.3 border group 2 promiscuous

MPAsource-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

MPBsource-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

MPCdlsw local-peer 10.1.1.4 group 2 promiscuous

dlsw remote-peer tcp 0 10.1.1.3

To verify that the DLSw+ Peer Clusters feature is enabled, issue the show dlsw capabilities

command or the show dlsw capabilities local command on the border peer or member peer.

BP2

MPC

Peer cluster

ID 5

MPB

MPA

BP1

Peer group 1 Peer group 2 17269

TokenRing


6/14

Configuration Examples


RAF

The following is output from the show dlsw capabilities command on BP1:

ibm-45k#show dlsw cap local

DLSw:Capabilities for local peer 10.1.1.3

vendor id (OUI) :'00C' (cisco)

version number :2

release number :0init pacing window :20

unsupported saps :none

num of tcp sessions :1

loop prevent support :no

icanreach mac-exclusive :no

icanreach netbios-excl. :no

reachable mac addresses :none

reachable netbios names :none

V2 multicast capable :yes

DLSw multicast address :none

cisco version number :1

peer group number :2

peer cluster support :yes------>indicates peer cluster feature enabled

border peer capable :yes

peer cost :3

biu-segment configured :no

UDP Unicast support :yes

cisco RSVP support :no

current border peer :local-peer

version string :

Cisco Internetwork Operating System Software

IOS (tm) 4500 Software (C4500-AJS-M), Experimental Version 12.0(19981113:101717)

[vtubati-120t_3_pi 110]

Copyright (c) 1986-1998 by cisco Systems, Inc.

Compiled Fri 13-Nov-98 10:33 by vtubati


7/14

Enable DLSw+ Peer Clusters on the Border Peer


The following is output from the show dlsw capabilities local command on MPB:

ibm-25kb#show dlsw cap local

DLSw:Capabilities for local peer 10.1.1.2

vendor id (OUI) :'00C' (cisco)

version number :2

release number :0init pacing window :20

unsupported saps :none

num of tcp sessions :1

loop prevent support :no

icanreach mac-exclusive :no

icanreach netbios-excl. :no

reachable mac addresses :none

reachable netbios names :none

V2 multicast capable :yes

DLSw multicast address :none

cisco version number :1

peer group number :2

peer cluster support :yes

peer cluster id :5------->Indicates the value configured for peer cluster id.

border peer capable :no

peer cost :3

biu-segment configured :no

UDP Unicast support :yes

cisco RSVP support :no

current border peer :peer 10.8.218.61(2065) cost 3

version string :

Cisco Internetwork Operating System Software

IOS (tm) 2500 Software (C2500-AJS-L), Experimental Version 12.0(19981113:101717)

[vtubati-120t_3_pi 114]

Copyright (c) 1986-1998 by cisco Systems, Inc.

Compiled Fri 13-Nov-98 15:49 by vtubati

Command ReferenceThis section documents new or modified commands. All other commands used with this feature aredocumented in the Cisco IOS Release 12.0 command references.

dlsw local-peer

dlsw remote-peer tcp


8/14

Command Reference


RAF

dlsw local-peerUse the dlsw local-peerglobal configurationcommand to define theparameters of theDLSw+ local

peer. Use the no form of this command to cancel the definitions.

dlsw local-peer [cluster cluster-id] [peer-id ip-address] [group group] [border] [cost cost]

[lfsize] [keepalive seconds] [passive] [promiscuous] [biu-segment][init-pacing-window size] [max-pacing-window size]

no dlsw local-peer [cluster cluster-id] [peer-id ip-address] [group group] [border] [cost cost]

[lfsize] [keepalive seconds] [passive] [promiscuous] [biu-segment]

[init-pacing-window size] [max-pacing-window size]

Syntax Description

cluster cluster-id (Optional) Implements the DLSw+ Peer Clusters feature and

defines the router as part of a particular cluster. The valid range

is 1 to 255.

peer-id ip-address (Optional) Local peer IP address. This address is required whenFast-Sequenced Transport (FST) or TCP is used.

group group (Optional) Peer group number for this router. The valid range is

1 to 255.

border (Optional) Enables the router as a border peer. The group option

must be specified to use the border peer option.

cost cost (Optional) Peer cost advertised to remote peers in the

capabilities exchange. The valid range is 1 to 5.

lfsize (Optional) Largest frame size for this local peer. Valid

maximum frame sizes are as follows:

516-516 byte

1470-1470 byte

1500-1500 byte

2052-2052 byte

4472-4472 byte

8144-8144 byte

11407-11407

11454-11454

17800-17800

keepalive seconds (Optional) Default remote peer keepalive interval in seconds.

The valid range is 0 to 1200 seconds. The default is 30 seconds.The value 0 means no keepalives.

passive (Optional) Specifies that this router does not initiate remote

peer connections to configured peers.

promiscuous (Optional) Accept connections from nonconfigured remote

peers.


9/14

dlsw local-peer


Default

No parameters are defined.

Command Mode

Global configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.3.

When there are multiple peers to a specific destination, use the cost keyword to determine which

router is preferred and which is capable. The cost keyword only applies in fault tolerance mode.

The biu-segment option is a performance and utilization improvement. If a frame that arrives from

a remote peer is too large for the destination station to handle, DLSw+ segments the frame. If you

choose to implement this option, you must add the option to both DLSw peer partners.

Example

The following command defines the local peer IP address and specifies the peer group number forthis router:

dlsw local-peer peer-id 10.2.17.1 group 2

Related Commands

dlsw duplicate-path-bias

show dlsw capabilities

biu-segment (Optional) DLSw+ spoofs the maximum receivable I-frame size

in XID so that each end station sends its largest frame.

init-pacing-window size (Optional) Size of the initial pacing window as defined in RFC

1795. The valid range is 1 to 2000.

max-pacing-window size (Optional) Maximum size of the pacing window as defined in

RFC 1795. The valid range is 1 to 2000.


10/14

Command Reference


RAF

dlsw remote-peer tcpUse the dlsw remote-peer tcp global configuration command to identify the IP address of a peer

with which to exchange traffic using TCP. Use theno form of this command to remove a remote peer.

dlswremote-peer list-numbertcp ip-address [backup-peer [ip-address | frame-relay interface

serial number dlci-number| interface name]] [bytes-netbios-out bytes-list-name][cluster cluster-id] [cost cost] [dest-mac mac-address]

[dmac-output-list access-list-number] [dynamic] [host-netbios-out host-list-name]

[inactivity minutes] [dynamic] [keepalive seconds] [lfsize] [linger minutes]

[lsap-output-list list] [no-llc minutes] [passive] [priority]

[rif-passthru virtual-ring-number] [tcp-queue-max size] [timeout seconds]

no dlsw remote-peer list-numbertcp ip-address [backup-peer [ip-address | frame-relay

interface serial number dlci-number| interface name]] [bytes-netbios-out bytes-list-name]

[cluster cluster-id] [cost cost] [dest-mac mac-address]

[dmac-output-list access-list-number] [dynamic] [host-netbios-out host-list-name]

[inactivity minutes] [dynamic] [keepalive seconds] [lfsize] [linger minutes]

[lsap-output-list list] [no-llc minutes] [passive] [priority]

[rif-passthru virtual-ring-number] [tcp-queue-max size] [timeout seconds]

Syntax Description

list-number Remote peer ring group list number. This ring group list

number default is 0. Otherwise, this value must match the

number you specify with the dlsw ring-list, dlsw port-list

or dlsw bgroup-list command.

tcp ip-address IP address of the remote peer with which the router is to

communicate.

backup-peer ip-address (Optional) IP address of the existing TCP/FST peer for

which this peer is the backup peer.

backup-peerframe-relay interface

serial number dlci-number

(Optional) Serial interface and DLCI number of the

existing Direct/LLC2 Frame-Relay peer for which this peer

is the backup peer.

backup-peer interface name (Optional) Interface name of the existing direct peer for

which this peer is the backup peer.

bytes-netbios-out bytes-list-name (Optional) Configures NetBIOS bytes output filtering for

this peer. The bytes-list-name argument is the name of the

previously defined NetBIOS bytes access list filter.

cluster cluster-id (Optional) Used to indicate to a border peer that aparticular remote-peer should be treated as part of a

specific peer cluster. The valid Range is 1 to 255.

cost cost (Optional) Cost to reach this remote peer. The valid range

is 1 to 5.

dest-mac mac-address (Optional) Establishes the TCP connection only when there

is an explorer frame destined for the specified 48-bit MAC

address written in dotted triplet form.


11/14



dmac-output-list

access-list-number

(Optional) Establishes the TCP connection only when the

explorer frame passes the specified access list. The

access-list-numberis the list number specified in the

access-list command.

dynamic (Optional) Establishes the TCP connection only when there

is DLSw+ data to send.

host-netbios-out host-list-name (Optional) Configures NetBIOS host output filtering for

this peer. The host-list-name is the name of the previously

defined NetBIOS host access list filter.

inactivity minutes (Optional) Length of time a connection is idle before

closing the dynamic remote peer connection. The valid

range is 1 to 300 minutes. The default is 5 minutes.

keepalive seconds Keepalive interval for this remote peer. The range is 0 to

1200 seconds.

lfsize (Optional) Largest frame size, in bytes, this local peer uses

on a circuit to avoid segmented frames. Valid sizes are 516,

1470, 1500, 2052, 4472, 8144, 11407, 11454, and 17800

bytes.

linger minutes (Optional) Length of time the backup peer remains

connected after the primary peer connection is

reestablished. The valid range is 1 to 300 minutes. The

default is 5 minutes.

lsap-output-list list (Optional) Filters output IEEE 802.5 encapsulated packets.

Valid access list numbers are 200 to 299.

no-llc minutes (Optional) Length of time a remote peer remains connected

after all LLC2 connections are gone. The valid range is 1 to

300 minutes. The default is 5 minutes.

passive (Optional) Designates this remote peer as passive.

priority (Optional) Enables prioritization features for this remote

peer. Valid TCP port numbers are the following:

High: 2065

Medium: 1981

Normal: 1982

Low: 1983

rif-passthru virtual-ring-number (Optional) Configures the remote peer as RIF-Passthru.

The virtual-ring-numbervalue is the same number as the

ring numbervalue assigned in the source-bridge

ring-group commands of the DLSw+ Passthru peers.


12/14

Command Reference


RAF

Defaults

No peer IP address is identified.

The linger option is inactive. If the linger option is added with no minutes specified, the default is

5 minutes.

The dynamic option is not on by default. If the dynamic option is added without either the inactivity

or no-llc argument specified, the default is to terminate the TCP connection to the remote peer after

5 minutes of no active LLC2 connection.

Command Mode

Global configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.3. The following keywords and arguments

first appeared in Cisco IOS Release 11.1: dynamic, inactivity minutes, linger minutes,

no-llc minutes and timeout seconds. The following keywords and arguments first appeared in

Cisco IOS Release 11.2: dest-mac mac-address, dmac-output-list access-list-number, linger

minutes.

SNA Dial-on-Demand Routing allows switched links to be closedduring idle periods. To enable this

feature, set the keepalive option to 0 and configure the timeout option. When the dynamic option

is configured, the keepalive option is automatically set to 0.

To enhance DDR cost savings, configure the TCP connection to a remote peer so it is dynamically

established (that is, established only when there is DLSw data to send). You can also configure the

TCP connection to terminate after a specified period of idle time on the peer or after a specified

period of no active LLC sessions on the peer.

You cannot use both no-llc and inactivity in a command specifying a dynamic peer.

When you need to permit access to a single MAC address, the dest-mac option takes less time to

configure than the dmac-output-list option.

Use the linger option to specify that a backup peer will remain connected for a specified period of

time after the primary connection is gone.

When the priority option on the dlsw remote-peer command is configured, DLSw+ automatically

activates four TCP ports to that remote peer (ports 2065, 1981, 1982 and 1983) and assigns traffic to

specific ports. Furthermore, if APPN is running with DLSw+ and you specify the priority option on

the dlsw remote-peer command, then the SNA TOS maps APPN COS to TCP TOS and preserves

the APPN COS characteristics throughout the network.

The rif passthru option works only on Token Ring LANs via SRB. Other LANtypes, such as SDLC

and QLLC, are not supported. The RIF Passthru feature is supported with TCP encapsulation and it

disables local acknowledgment.

tcp-queue-max size (Optional) Maximum output TCP queue size for this

remote peer. The valid maximum TCP queue size is

10 to 2000.

timeout seconds (Optional) Retransmit time limit for TCP. The valid range

is 5 to 1200 seconds. The default is 90 seconds.


13/14



The following features are not supported with the DLSw+ RIF Passthru feature:

Border peers

Peer-on-demand peers

Dynamic peers

Backup peers

The cluster keyword is available only on border peers.This optionenables the DLSw+ Peer Clusters

feature without forcing every DLSw+ router in the network to upgrade their software.

Examples

The following example specifies a TCP encapsulation connection for remote peer transport:

dlsw remote-peer 0 tcp 10.2.17.8

The following example specifies a TCP peer as backup to a primary FST peer:

dlsw remote-peer 0 fst 10.2.18.9dlsw remote-peer 0 tcp 10.2.17.8 backup-peer 10.2.18.9

Related Commands

show dlsw peers


14/14

Command Reference


RAF

3600 dlsw peer group clusters

Documents