Understanding Vsl Topology - Cisco Catalyst 4500 series Administration Manual

Chapter 5 Configuring Virtual Switching Systems
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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
In-chassis Standby
VSS Redundancy
The following sections describe how redundancy in a VSS supports network high availability:
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OL-30933-01
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.
VSL Topology Example
VSS Active
Linecard 1
Linecard 2
Linecard N
Active chassis
Overview, page 5-12
RPR and SSO Redundancy, page 5-12
Switch Roles in a VSS, page 5-12
Failed Switch Recovery, page 5-13
VSL Failure, page 5-14
User Actions, page 5-14
Figure 5-5 shows a example topology.
VSL
VSS Standby
In-chassis Standby
Linecard 1
Linecard 2
Linecard N
Standby chassis
Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)SG
Understanding Virtual Switching Systems
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