Downloads |
Table Of Contents
Enable DLSw+ Peer Clusters on Local Router
Enable DLSw+ Peer Clusters on the Border Peer
DLSw+ Peer Group Clusters
Feature Summary
In 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 typically fixed 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 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 the explorers are duplicated when the border peer forwards an explorer within it's Peer Group. In , BP2 forwards the explorer to all the routers in Peer Group 2 (including MPA and 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.
Benefits
The 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 DLSw+ with the DLSw+ Peer Clusters Feature Configured
In , 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 MP's in Peer Group 2, BP1—>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 still additional 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.
Using again, but this time with the DLSw+ Peer Clusters feature configured, BP2 recognizes that MPA and MPB belong to peer cluster 5 and the explorer takes the following path:
•
•
•
List of Terms
Border peer—DLSw+ router that relays reachability information to other border and member peers.
Member peer—DLSw+ router is a member of a peer group that relies on the border peer to act as its proxy for exploring the network, rather than exploring the network itself.
Peer cluster—Virtual arrangement of peers that allows multiple peers to be connected to the same LAN without explorer replication.
Peer group—Predefined grouping of DLSw+ peers that allows meshed configurations to be broken into more scalable units. A peer group consists of a border peer with one or more member peer.s
Platforms
This feature is supported on the following platforms:
•
•
•
•
•
•
•
•
•
Supported MIBs and RFCs
No MIBs are supported by this feature.
This feature supports the following RFCs:
•
•
Configuration Tasks
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.
Enable DLSw+ Peer Clusters on Local Router
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.
To enable the DLSw+ Peer Clusters feature on the member peer, use the following command in global configuration mode:
dlsw local-peer [cluster cluster-id]
Defines the Member Peer as part of a particular cluster and enables the DLSw+ Peer Clusters feature locally.
Enable DLSw+ Peer Clusters on the Border Peer
When 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:
Configuration Examples
shows 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.
BP2
source-bridge ring-group 310dlsw local-peer 10.1.1.3 border group 2 promiscuousMPA
source-bridge ring-group 310dlsw local-peer 10.1.1.1 group 2 promiscuous cluster 5dlsw remote-peer 0 tcp 10.1.1.3MPB
source-bridge ring-group 310dlsw local-peer 10.1.1.2 group 2 promiscuous cluster 5dlsw remote-peer tcp 0 10.1.1.3MPC
dlsw local-peer 10.1.1.4 group 2 promiscuousdlsw remote-peer tcp 0 10.1.1.3To 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.
The following is output from the show dlsw capabilities command on BP1:
ibm-45k#show dlsw cap localDLSw:Capabilities for local peer 10.1.1.3vendor id (OUI) :'00C' (cisco)version number :2release number :0init pacing window :20unsupported saps :nonenum of tcp sessions :1loop prevent support :noicanreach mac-exclusive :noicanreach netbios-excl. :noreachable mac addresses :nonereachable netbios names :noneV2 multicast capable :yesDLSw multicast address :nonecisco version number :1peer group number :2peer cluster support :yes------>indicates peer cluster feature enabledborder peer capable :yespeer cost :3biu-segment configured :noUDP Unicast support :yescisco RSVP support :nocurrent border peer :local-peerversion string :Cisco Internetwork Operating System SoftwareIOS (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 vtubatiThe following is output from the show dlsw capabilities local command on MPB:
ibm-25kb#show dlsw cap localDLSw:Capabilities for local peer 10.1.1.2vendor id (OUI) :'00C' (cisco)version number :2release number :0init pacing window :20unsupported saps :nonenum of tcp sessions :1loop prevent support :noicanreach mac-exclusive :noicanreach netbios-excl. :noreachable mac addresses :nonereachable netbios names :noneV2 multicast capable :yesDLSw multicast address :nonecisco version number :1peer group number :2peer cluster support :yespeer cluster id :5------->Indicates the value configured for peer cluster id.border peer capable :nopeer cost :3biu-segment configured :noUDP Unicast support :yescisco RSVP support :nocurrent border peer :peer 10.8.218.61(2065) cost 3version string :Cisco Internetwork Operating System SoftwareIOS (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 vtubatiCommand Reference
This section documents new or modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command references.
dlsw local-peer
Use the dlsw local-peer global configuration command to define the parameters of the DLSw+ 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]
[lf size] [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]
[lf size] [keepalive seconds] [passive] [promiscuous] [biu-segment]
[init-pacing-window size] [max-pacing-window size]Syntax Description
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 for this router:
dlsw local-peer peer-id 10.2.17.1 group 2Related Commands
dlsw duplicate-path-bias
show dlsw capabilitiesdlsw remote-peer tcp
Use the dlsw remote-peer tcp global configuration command to identify the IP address of a peer with which to exchange traffic using TCP. Use the no form of this command to remove a remote peer.
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]
[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] [lf size] [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-number tcp 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] [lf size] [linger minutes]
[lsap-output-list list] [no-llc minutes] [passive] [priority]
[rif-passthru virtual-ring-number] [tcp-queue-max size] [timeout seconds]Syntax Description
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 closed during 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 LAN types, such as SDLC and QLLC, are not supported. The RIF Passthru feature is supported with TCP encapsulation and it disables local acknowledgment.
The following features are not supported with the DLSw+ RIF Passthru feature:
•
•
•
•
The cluster keyword is available only on border peers.This option enables 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 10.2.17.8The 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 10.2.18.9Related Commands
