Cisco Catalyst 4500 Series - Multichassis Etherchannel Restrictions and Guidelines

5-30
Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)SG
OL-30933-01
Chapter 5 Configuring Virtual Switching Systems
Configuring a VSS
Multichassis EtherChannel Restrictions and Guidelines
When configuring MECs, note the following guidelines and restrictions:
• Port Security over EtherChannels is not supported.
• All links in an MEC must terminate locally on the VSS Active or VSS Standby switch of the same
virtual domain.
• An MEC can be connected to another MEC on a different VSS domain.
• Policers applied on an MEC are applied on two switches independently; if a policer is applied for
100 Mbps of conforming action, it will apply 100Mbps on both switches, resulting in a total
conforming rate of 200 Mbps. To mitigate this, you can reduce the policer rate. In a more restrictive
case, a rate of 50 Mbps might be necessary to achieve a maximum of 100Mbps. In a more liberal
case, where conforming action of 200 Mbps is not a problem, policing rate could be kept to
100Mbps.
Dual-Active Detection Restrictions and Guidelines
When configuring dual-active detection, note the following guidelines and restrictions:
• For line redundancy, we recommend configuring at least two ports per switch for dual-active
detection. For module redundancy, the two ports can be on different modules in each switch, and
should be on different modules than the VSL ports, if feasible.
• Only trusted PAgP channels are relied upon to detect dual-active mode of operation.
Configuring a VSS
These sections describe how to configure a VSS:
• Configuring Easy VSS, page 5-30
• Converting to a VSS, page 5-32
• Displaying VSS Information, page 5-38
• Converting a VSS to Standalone Switch, page 5-39
• Configuring VSS Parameters, page 5-41
• Configuring Multichassis EtherChannels, page 5-47
• Configuring Dual-Active Detection, page 5-51
Configuring Easy VSS
Beginning with Cisco IOS XE 3.6.0E (IOS 15.2(2)E), the Catalyst 4500 series switch supports Easy
VSS, which enables you to configure VSS with a single command on the active switch and no action on
the VSS standby switch.
The active switch can gather information from all switches that are Layer 3 reachable.