Displaying Dual-Active Detection - Cisco Catalyst 4500 Series Software Configuration Manual

Configuring a VSS
When you configure fast hello dual-active interface pairs, note the following information:
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This example shows how to configure an interface for fast hello dual-active detection:
Switch(config)# switch virtual domain 255
Switch(config-vs-domain)# dual-active detection fast-hello
Switch(config-vs-domain)# exit
Switch(config)# interface fastethernet 1/2/40
Switch(config-if)# dual-active fast-hello
WARNING: Interface FastEthernet1/2/40 placed in restricted config mode. All extraneous
configs removed!
Switch(config-if)# no shutdown
Switch(config-if)# exit
Switch(config)# exit
Switch# show run interface fastethernet 1/2/40
interface FastEthernet1/2/40
switchport mode access
switchport nonegotiate
dual-active fast-hello
no switchport
no ip address
dual-active fast-hello
end

Displaying Dual-Active Detection

To display information about dual-active detection, perform this task:
Command
show switch virtual [dual-active {pagp |
Switch#
fast-hello | summary} | link [counters | detail |
port-channel | ports] | redundancy | role | slot-map]
This example shows how to display the summary status for dual-active detection:
Switch# show switch virtual dual-active summary
Switch(recovery-mode)# show switch virtual dual-act summary
Pagp dual-active detection enabled: Yes
In dual-active recovery mode: Yes
Triggered by: PagP
Triggered on Interface: Gi1/3/11
Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
5-54
You can configure a maximum of four interfaces on each chassis to connect with the other chassis
in dual-active interface pairs. Attempting to configure more than four interfaces causes an error
message to display (and your command is rejected).
Each interface must be directly connected to the other chassis and must not be a VSL link. We
recommend using links from a switching module not used by the VSL.
Each interface must be a physical port. Logical ports such as an SVI are not supported.
The fast-hello links are Layer 2 ports.
Configuring fast hello dual-active mode automatically removes all existing configuration from the
interface and restricts the interface to fast hello dual-active configuration commands. It can only be
used for "fast-hello" traffic.
Unidirectional link detection (UDLD) is disabled on fast hello dual-active interface pairs.
Do not configure fast-hello ports on an oversubscribed line card. Doing so might lead to a loss of
fast-hello messages, impacting the functionality of fast-hello based dual-active detection.
Chapter 5 Configuring Virtual Switching Systems
Purpose
Displays information about dual-active detection
configuration and status.