A Token Ring VLAN represents a single logical ring with one ring number. A Token Ring
concentrator relay function (TRCRF) VLAN defines groups of ports with the same logical
ring number. You can configure undistributed and backup TRCRFs in your network. 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 Token Ring bridge relay function (TRBRF). The parent TRBRF acts as a
multiport bridge, forwarding traffic between the undistributed TRCRFs.
A backup concentrator relay function (CRF) provides an alternate route for traffic
between undistributed TRCRFs located on separate switches that are connected by a TRBRF in
the event that the ISL trunk 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. If the
ISL trunk connection between the switches fails, the port in the backup TRCRF on each
affected switch automatically becomes active, rerouting traffic between the undistributed
TRCRFs through the backup TRCRF. When the ISL trunk connection is reestablished, all but
one port in the backup TRCRF is disabled. Note that IEEE 802.1Q trunking is not supported
on TRCRF VLANs.
Note: This switch only supports Ethernet interfaces. You configure
Token Ring media-specific characteristics only for VLAN Trunk Protocol (VTP) global
advertisements to other switches.
To configure Token Ring-specific VLAN characteristics:
In the VLAN ID field, enter the number of the Token Ring VLAN.
In the VLAN Name field, enter a VLAN name from 1 to 32 characters that is unique within
the administrative domain.
The default name is "VLANxxxx" where "xxxx" represents four digits
(including leading zeros) equal to the VLAN ID number.
Select Token Ring/TRCRF from the VLAN Media Type drop-down list.
In the 802.10 SAID (security association identifier) field, enter a number from 1 to
4294967294 that is unique within the administrative domain.
The default is 100000 plus the VLAN ID.
In the MTU Size field, enter a number from 1500 to 18190 for the maximum transmission
unit (packet size in bytes) that the VLAN can use.
The default is 1500.
If you are translationally bridging from one VLAN type to another (such as from Token
Ring to Ethernet), in the Translational Bridge 1 and Translational Bridge 2 fields, enter
the VLAN IDs (from 0 to 1005) of the two VLANs to which this VLAN is translationally
bridging. Note: By default, these fields are set to zero, which means translational
bridging is not in effect.
In the VLAN Status drop-down list, select Active.
By default, Suspended is selected. When the status is suspended, all traffic for that VLAN
is blocked on all switches in the management domain.
In the Ring Number field, enter a logical ring number from 1 to 4095.
The ring number is used for source routing. The default is 0.
In the Parent VLAN field, enter a parent VLAN ID number from 0 to 1005. Note: By default, this field is set to zero, which means no parent VLAN
is defined.
The parent VLAN of a Token Ring VLAN must be a Token Ring-NET VLAN, which represents a set
of ring segments connected by source-route bridges. The parent VLAN is the VLAN ID to
which the Token Ring VLAN is attached for source routing functions.
Click OK to put your changes in effect and close the VLAN Configuration
dialog box.
If you created a new VLAN, the new VLAN is displayed on the VLAN Configuration tab.