Cisco Catalyst 4500 Series - Page 230

5-4
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
Figure 5-3 Virtual Switch Link
When you configure VSL, all existing configurations are removed from the interface except for specific
allowed commands. When you configure VSL, the system puts the interface into a restricted mode. This
means that only specific configuration commands can be configured on the interface.
The following VSL configuration commands are inserted automatically on all VSL member ports:
• switchport mode trunk
• switchport nonegotiate
• no lldp transmit
• no lldp receive
• no cdp enable
• service-policy output VSL-Queuing-Policy
In VSL restricted mode, only these configuration commands are available:
• channel-group
• default
• description
• exit
• load-interval
• logging
• no
• power
• service-policy
• shutdown
Multichassis EtherChannel
Note Beginning with Cisco Release IOS XE 3.5.0E and IOS 15.2(1)SG, Layer 3 MEC is supported on the
Catalyst 4500 series switch. Cisco Release IOS XE 3.4.0SG does not support Layer 3 MEC.
An EtherChannel (also known as a port channel) is a collection of two or more physical links that
combine to form one logical link. Layer 2 protocols operate on the EtherChannel as a single logical
entity. A VSS enables the creation of Multi-Chassis EtherChannel (MEC), which is an Etherchannel
whose member ports can be distributed across the member switches in a VSS. Because non-VSS
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Virtual switch link
(VSL)
Virtual switch
Chassis 1 Chassis 2