13-3
Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 13 Configuring VLANs, VTP, and VMPS
VLANs
• VLAN state (active or suspended)
• Maximum transmission unit (MTU) for the VLAN
• Security Association Identifier (SAID)
• VLAN number to use when translating from one VLAN type to another
Note When the software translates from one VLAN type to another, it requires a different VLAN number for
each media type.
VLAN Configuration Guidelines and Restrictions
Follow these guidelines and restrictions when creating and modifying VLANs in your network:
• Before creating a VLAN, put the Catalyst 4500 series switch in VTP server mode or VTP
transparent mode. If the Catalyst 4500 series switch is a VTP server, you must define a VTP domain.
For information on configuring VTP, see the “VLAN Trunking Protocol” section on page 13-7.
• You cannot use the end command in VLAN database mode.
• You cannot use Ctrl-Z to exit VLAN database mode.
• If a Catalyst 4948 switch running MSTP and configured with all possible VLANs (4094) is in the
path of two HSRP peers with the timeout set below 500 ms, HSRP flaps.
Workarounds:
–
Use fewer VLANs.
–
Set the timers greater than 600 ms.
–
Enter the no igmp snooping (globally) and access-list hardware capture mode VLAN
commands
VLAN Ranges
Note You must enable the extended system ID to use 4094 VLANs. See the “Understanding the Bridge ID”
section on page 18-2.
With Cisco IOS Release 12.2(25)EWA and later, Catalyst 4500 series switches support 4096 VLANs in
compliance with the IEEE 802.1Q standard. These VLANs are organized into three ranges: reserved,
normal, and extended.
Some of these VLANs are propagated to other switches in the network when you use the VLAN
Trunking Protocol (VTP). The extended-range VLANs are not propagated, so you must configure
extended-range VLANs manually on each network device.
