Cisco WS-X6066-SLB-APC - Content Switching Module Software Manual page 208

Configuring Token Ring VLANs
Typically, TrCRFs are undistributed, which means each TrCRF is limited to the ports on a single switch.
Multiple undistributed TrCRFs on the same or separate switches can be associated with a single parent
TrBRF (see
undistributed TrCRFs.
To pass data between rings located on separate switches, you can associate the rings to the same
Note
TrBRF and configure the TrBRF for SRB.
Figure 11-3 Undistributed TrCRFs
By default, Token Ring ports are associated with the default TrCRF (VLAN 1003, trcrf-default),
Note
which has the default TrBRF (VLAN 1005, trbrf-default) as its parent. In this configuration, a
distributed TrCRF is possible (see
located on separate switches provided that the switches are connected through an ISL trunk.
Figure 11-4 Distributed TrCRF
Within a TrCRF, source-route switching forwards frames based on either MAC addresses or route
descriptors. The entire VLAN can operate as a single ring, with frames switched between ports within a
single TrCRF.
You can specify the maximum hop count for All-Routes and Spanning Tree Explorer frames for each
TrCRF. This limits the maximum number of hops an explorer is allowed to traverse. If a port determines
that the explorer frame it is receiving has traversed more than the number of hops specified, it does not
forward the frame. The TrCRF determines the number of hops an explorer has traversed based on the
number of bridge hops in the route information field.
A backup TrCRF enables you to configure an alternate route for traffic between undistributed TrCRFs
located on separate switches that are connected by a TrBRF, in the event that the ISL connection between
the switches fails. Only one backup TrCRF for a TrBRF is allowed, and only one port per switch can
belong to a backup TrCRF.
Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
11-26
Figure 11-3). The parent TrBRF acts as a multiport bridge, forwarding traffic between the
Switch A
ISL
TrBRF 3
TrCRF
400
Switch A
ISL
TrBRF 2
TrCRF
300
Switch B
TrCRF TrCRF
350 200
Figure 11-4), and traffic is passed between the default TrCRFs
Switch B
TrCRF TrCRF
300 300
Chapter 11 Configuring VLANs
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