Cisco Catalyst 4500 Series - Understanding VSL Topology

5-10
Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 5 Configuring Virtual Switching Systems
Understanding Virtual Switching Systems
• Oversubscribed linecard ports can be used for VSL but total bandwidth requirements of VSL or any
traffic drop because of a certain hashing mechanism must be accounted for before using
oversubscribed linecard ports for VSL.
• VSL ports can have only 10 Gigabit Ethernet port mode on a WS-X4606-X2-E linecard; non-VSL
ports can be configured as 10 or 1 Gigabit Ethernet port mode.
• 1 Gigabit Ethernet ports on line card X4606-X2-E cannot be used as VSL links.
Multichassis EtherChannel Requirements
Physical links from any of the supervisor engines or linecard modules can be used to implement a
Multichassis EtherChannel (MEC).
Understanding VSL Topology
A VSS contains two switches that communicate using the VSL, which is a special port group.
We recommend that you configure at least two of the 10-Gigabit/1-Gigabit Ethernet ports as VSL,
selecting ports from different modules. Figure 5-5 shows a example topology.
Figure 5-5 VSL Topology Example
VSS Redundancy
The following sections describe how redundancy in a VSS supports network high availability:
• Overview, page 5-11
• RPR and SSO Redundancy, page 5-11
• Switch Roles in a VSS, page 5-11
• Failed Switch Recovery, page 5-12
• VSL Failure, page 5-13
• User Actions, page 5-13
VSS Active
In-chassis Standby
Linecard 1
Linecard 2
Linecard N
VSS Standby
In-chassis Standby
Linecard 1
Linecard 2
Linecard N
Active chassis Standby chassis
181326
VSL