Understanding vsl topology, Vss redundancy, Overview – Cisco 6500 User Manual
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Cisco IOS Software Configuration Guide, Release 12.2SX
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Chapter 4 Configuring Virtual Switching Systems
Understanding Virtual Switching Systems
Understanding VSL Topology
A VSS contains two chassis that communicate using the VSL, which is a special port group.
We recommend that you configure both of the 10-Gigabit Ethernet ports on the supervisor engines as
VSL ports. Optionally, you can also configure the VSL port group to contain switching module
10-Gigabit Ethernet ports. This configuration provides additional VSL capacity. See
example topology.
Figure 4-6
VSL Topology Example
VSS Redundancy
The following sections describe how redundancy in a VSS supports network high availability:
•
•
RPR and SSO Redundancy, page 4-12
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Failed Chassis Recovery, page 4-13
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•
Overview
A VSS operates stateful switchover (SSO) between the VSS active and VSS standby supervisor engines.
Compared to standalone mode, a VSS has the following important differences in its redundancy model:
•
The VSS active and VSS standby supervisor engines are hosted in separate chassis and use the VSL
to exchange information.
•
The VSS active supervisor engine controls both chassis of the VSS. The VSS active supervisor
engine runs the Layer 2 and Layer 3 control protocols and manages the switching modules on both
chassis.
•
The VSS active and VSS standby chassis both perform data traffic forwarding.
If the VSS active supervisor engine fails, the VSS standby supervisor engine initiates a switchover and
assumes the VSS active role.
Active
Supervisor
Linecard 1
Linecard 2
Linecard N
Standby
Supervisor
Linecard 1
Linecard 2
Linecard N
Active chassis
Standby chassis
181326
VSL