Cisco 7609 User Manual

9-8
Cisco 7600 Series Router Cisco IOS Software Configuration Guide—12.1E
78-14064-04
Chapter 9 Configuring VLANs
VLAN Configuration Guidelines and Restrictions
VLAN Configuration Guidelines and Restrictions
Follow these guidelines and restrictions when creating and modifying VLANs in your network:
Restrictions
• Supervisor engine redundancy does not support nondefault VLAN data file names or locations. Do
not enter the vtp file file_name command on a router that has a redundant supervisor engine.
• RPR+ redundancy (see Chapter 5, “Configuring RPR and RPR+ Supervisor Engine Redundancy”)
does not support a configuration entered in VLAN database mode. Use global configuration mode
with RPR+ redundancy.
• You can configure extended-range VLANs only in global configuration mode. You cannot configure
extended-range VLANs in VLAN database mode. See the “VLAN Configuration Options” section
on page 9-9.
• The Cisco IOS end command is not supported in VLAN database mode.
• You cannot enter Ctrl-Z to exit VLAN database mode.
• Cisco 7600 series routers do not support Token Ring or FDDI media. The router does not forward
FDDI, FDDI-Net, TrCRF, or TrBRF traffic, but it can propagate the VLAN configuration through
VTP.
• In a Token Ring environment, the logical interfaces (the connection between the TrBRF and the
TrCRF) of the TrBRF are placed in a blocked state if either of these conditions exists:
– The TrBRF is running the IBM STP, and the TrCRF is in SRT mode.
– The TrBRF is running the IEEE STP, and the TrCRF is in SRB mode.
Guidelines
• Before installing a redundant supervisor engine, enter the no vtp file command to return to the
default configuration.
• Before you can create a VLAN, the Cisco 7600 series router must be in VTP server mode or VTP
transparent mode. For information on configuring VTP, see Chapter 8, “Configuring VTP.”
• The VLAN configuration is stored in the vlan.dat file, which is stored in nonvolatile memory. You
can cause inconsistency in the VLAN database if you manually delete the vlan.dat file. If you want
to modify the VLAN configuration or VTP, use the commands described in this guide and in the
Cisco 7600 Series Router Cisco IOS Command Reference publication.
• To do a complete backup of your configuration, include the vlan.dat file in the backup.
MTU size VTPv1 1500; VTPv2 4472 1500–18190
Bridge number 1 0–15
STP type ibm auto, ibm, ieee
VLAN state active active, suspend
Table 9-6 Token Ring (TrBRF) VLAN Defaults and Ranges (continued)
Parameter Default Range

Cisco 7609 Specifications

General

Brand	Cisco
Model	7609
Category	Network Router
Language	English