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However, some environments do not function properly if the RIF is terminated. For that reason, DLSw+ now supports the RIF Passthru feature, in which the entire source-route bridged path appears in the RIF.
Figure 1 shows a DLSw+ network without the RIF Passthru feature configured.
Figure 2 shows a DLSw+ network with the RIF Passthru feature configured.
When DLSw+ is used between FEPs (PU 4s), the RIF Passthru feature enables two key functions. First, RIF Passthru is required to allow multiple active paths between FEPs. Second, RIF Passthru is required to remotely load an NCP (in other words, set initialization mode/request initialization mode support).
Set initialization mode--DLC command that initiates system-specified procedures to initialize link-level functions.
Request initialization mode--DLC command that requests system-specified procedures to initialize link-level functions
Remote NCP load--Operation that occurs when an IBM 3745 does not contain a network control program (NCP). The IBM 3745 replies with request initialization mode when it is contacted by the host. The host (partner NCP) sends a set initialization mode, and then remotely transmits an NCP to the IBM 3745.
The DLSw+ RIF Passthru feature 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:
This feature is supported on the following platforms:
The source-bridge ring can be shared between DLSw+ and SRB/RSRB. In DLSw+, the source-bridge ring group specifies the virtual ring that will appear to be the last ring in the RIF. Because RIFs are terminated at the router, there is no correlation between the ring-group number specified in DLSw+ peers. The numbers can be the same for management simplicity, but they do not have to be the same.
In DLSw+ with RIF Passthru, however, the ring numbers must be unique throughout the network and DLSw peers must have the same virtual ring number because RIFs are passed through.
| Task | Command |
|---|---|
| Define a ring group. | source-bridge ring-group ring-group [virtual-mac-address] |
Defining a DLSw+ local peer for a router enables DLSw+. You specify all local DLSw+ parameters as part of the local peer definition. To define a local peer, perform the following task in global configuration mode:
| Task | Command |
|---|---|
| Define the DLSw+ local peer. | dlsw local-peer [peer-id ip-address] [group group] [border] [cost cost] [lf size] [keepalive seconds] [passive] [promiscuous] [ init-pacing-window size] [max-pacing-window size][biu-segment] |
To enable DLSw+ on a Token Ring interface, perform the following task in interface configuration mode:
| Task | Command |
|---|---|
| Enable DLSw+ on a Token Ring interface. | source-bridge local-ring bridge-number ring-group |
None.
To configure DLSw+ RIF Passthru, define the DLSw+ remote peer with TCP encapsulation.
To configure TCP encapsulation on a remote peer, perform the following task in global configuration mode:
| Task | Command |
|---|---|
| Define a TCP encapsulation 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] [cost cost] [dest-mac mac-address] [dmac-output-list access-list-number] [dynamic] [host-netbios-out host-list-name] [keepalive seconds] [lf size] [linger minutes] [lsap-output-list list] [no-llc minutes] [priority] [rif-passthru virtual ring number] [tcp-queue-max size] [timeout seconds] |
Figure 3 is a sample configuration for DLSw+ using the RIF Passthru feature.
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 tokenring 0 ring-speed 16 source-bridge 25 1 100 source-bridge spanning
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 tokenring 0 ring-speed 16 source-bridge 51 1 100 source-bridge spanning
This section documents new or modified commands. All other commands used with this feature are documented in the Cisco IOS Release 11.3 command references.
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| 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-peer frame-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. |
| cost cost | (Optional) The cost to reach this remote peer. The valid range is 1 to 5. |
| dest-mac mac-address | (Optional) Permits the TCP connection to be established only when there is an explorer frame destined for the specified 48-bit MAC address written in dotted triplet form. |
| dmac-output-list access-list-number | (Optional) Permits the TCP connection to be established only when the explorer frame passes the specified access list. The access-list-number is the list number specified in an access-list command. |
| dynamic | (Optional) Permits the TCP connection to be established 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) Configures the length of time a connection can be idle before closing the dynamic remote peer connection. The valid range is 1 to 300 minutes. The default is 5 minutes. |
| keepalive seconds | (Optional) Sets the keepalive interval for this remote peer. The range is 0 to 1200 seconds. The default is 30 seconds in the absence of any data being sent over the peer connection. |
| lf size | (Optional) Largest frame size, in bytes, this local peer will use on a circuit to avoid segmented frames. Valid sizes are 516, 1470, 1500, 2052, 4472, 8144, 11407, 11454, and 17800 bytes. |
| linger minutes | (Optional) Configures 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 in the range 200 to 299. |
| no-llc minutes | (Optional) Configures the 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 number value is the same number as the ring number value assigned in the source-bridge ring-group commands of the DLSw+ Passthru peers. |
| tcp-queue-max size | (Optional) Maximum output TCP queue size for this remote peer. The valid maximum TCP queue size is a number in the range 10 to 2000. The default queue size is 200. |
| timeout seconds | (Optional) Configures the retransmit time limit for TCP. The valid range is 5 to 1200 seconds. The default is 90 seconds. |
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.
Global configuration
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. The following keyword first appeared in Cisco IOS Release 11.3 T: rif-passthru virtual ring number.
SNA DDR technology 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, you can configure the TCP connection to a remote peer to be dynamically established (that is, established only when there is DLSw data to send). You can further 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 is a shortcut over 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 will map APPN class of service (COS) to TCP TOS and will preserve the APPN COS characteristics throughout the network.
The following example specifies a TCP peer as backup to a primary FST peer:
dlsw remote-peer 0 fst 10.2.18.9 dlsw remote-peer 1 tcp 10.2.17.8 backup-peer 10.2.18.9
The following example specifies a TCP encapsulation connection for remote peer transport:
dlsw remote-peer 1 tcp 10.2.17.8
The following is an example policy routing configuration that shows how to modify the default setting of TCP port 2065. The configuration changes the default setting on IP packets from network control precedence to routine precedence.
ip local policy route-map test access-list 101 permit tcp any eq 2065 any access-list 101 permit tcp any any eq 2065 route-map test permit 20 match ip address 101 set ip precedence routine
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