Displaying Etherchannel Links To Vss - Cisco Catalyst 4500 Series Configuration Manual

Understanding Link-State Tracking

Displaying EtherChannel Links to VSS

To display the dual-active detection capability of a configured PAgP port channel, enter the
show pagp port_channel_number dual-active command.
The command provides the following information:
•
•
•
Note You can also see the name of the neighboring switch (Partner Name) and the ports to which this
EtherChannel is connected (Partner Port).
If a Catalyst 4500 switch is connected to a Catalyst 6500 series VSS with the same version of enhanced
PAgP dual-active detection, the switch can detect a dual-active scenario:
Switch# show pagp 1 dual-active
PAgP dual-active detection enabled: Yes
PAgP dual-active version: 1.1
Channel group 1
Port
Gi6/5
Gi6/6
If a Catalyst 4500 switch is not connected to a Catalyst 6500 series VSS, the switch cannot detect a
dual-active scenario:
Switch# show pagp 1 dual-active
PAgP dual-active detection enabled: Yes
PAgP dual-active version: 1.1
Channel group 1
Port
Gi6/5
Gi6/6
Understanding Link-State Tracking
Link-state tracking, also known as trunk failover, is a feature that binds the link state of multiple
interfaces. For example, link-state tracking provides redundancy in the network when used with server
NIC adapter teaming. When server network adapters are configured in a primary or secondary
relationship known as teaming, if the link is lost on the primary interface, connectivity is transparently
changed to the secondary interface.
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
24-18
A switch uses enhanced PAgP for dual-active detection.
You should always see Yes after PAgP dual-active diction enabled on a Catalyst 4500 switch.
The configured PAgP EtherChannel is connected to a Catalyst 6500 switch VSS.
You see N/A below Partner Version if this EtherChannel is not connected to a VSS. Otherwise, you
see the version of enhanced PAgP dual-active detection implemented in the VSS.
This switch is capable of detecting dual-active scenarios in the connected VSS.
You see Yes below Dual-Active Detect Capable if and only if the configured EtherChannel is
connected to a Catalyst 6500 series VSS that uses the same version of enhanced PAgP dual-active
detection.
Dual-Active Partner
Detect Capable Name
Yes VSS
Yes VSS
Dual-Active Partner
Detect Capable Name
No Switch
No Switch
Chapter 24 Configuring EtherChannel and Link State Tracking
Partner Partner
Port Version
Gi1/8/1 1.1
Gi2/8/1 1.1
Partner Partner
Port Version
Fa6/5 N/A
Fa6/6 N/A
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