Cisco Catalyst 4500 Series Administration Guide

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Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)E
OL_28731-01
Chapter 26 Configuring EtherChannel and Link State Tracking
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:
• 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.
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
Dual-Active Partner Partner Partner
Port Detect Capable Name Port Version
Gi6/5 Yes VSS Gi1/8/1 1.1
Gi6/6 Yes VSS Gi2/8/1 1.1
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
Dual-Active Partner Partner Partner
Port Detect Capable Name Port Version
Gi6/5 No Switch Fa6/5 N/A
Gi6/6 No Switch Fa6/6 N/A
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.

Cisco Catalyst 4500 Series Specifications

General

Series	Catalyst 4500 Series
Category	Switch
Layer Support	Layer 2, Layer 3
Form Factor	Modular chassis
Stackable	No
Chassis Slots	3, 6, 7, 10
Power Supply Options	AC, DC
Redundancy	Power supply, Supervisor engine
Network Management	Cisco IOS Software CLI, SNMP, Cisco Prime Infrastructure
Features	Security, QoS
Port Density	Up to 384 ports per chassis
Security Features	802.1X, ACLs, DHCP Snooping, Dynamic ARP Inspection, IP Source Guard
Supervisor Engine	8-E