VSS deployment

Network and objective

Legacy Catalyst 6500 VSS with compatible supervisors and software only. This is not a Catalyst 9300 stacking or StackWise Virtual recipe. Conversion reloads chassis and requires a planned outage.

Two clean lab chassis become domain 10: SW1 is switch 1 and SW2 is switch 2. Supported TenGigabitEthernet1/5/4 and 1/5/5 ports are VSL members on each standalone chassis before conversion; physical port names must match the actual module.

Ethernet switchingIllustrative topology

How it works

Inventory and back up both standalone systems before conversion. Confirm a supported software image and matching VSS requirements, then configure a common domain with different switch numbers. Do not connect a production access network until the logical system is stable.

Each side needs a VSL port-channel tied to its local switch identity. The VSL is not an ordinary user trunk; use only documented VSL-capable interfaces and follow the platform restrictions. Conversion changes interface naming and stored configuration.

After conversion, verify active/standby hot state, VSL health, and an independent dual-active detection mechanism. VSL redundancy alone is not dual-active detection. A suitable dedicated fast-hello path is one supported option on relevant releases.

Configure or inspect

switch virtual domain 10
 switch 1
exit
interface Port-channel10
 switch virtual link 1
exit
interface range TenGigabitEthernet1/5/4 - 5
 channel-group 10 mode on
 no shutdown
end
write memory

Verify the result

SW1#show switch virtual
Virtual switch domain number: 10
Local switch number: 1
Operational role: Virtual Switch Active
Peer role: Virtual Switch Standby
SW1#show switch virtual link
VSL Status: UP
SW1#show redundancy states
my state = ACTIVE
peer state = STANDBY HOT

The configuration shows the switch-1 side only. On SW2 use switch 2, switch virtual link 2, and its own VSL port-channel. Then run switch convert mode virtual on each chassis in the planned sequence; it reloads them. The output is the expected post-conversion state, not proof that merely entering the preparation lines converts the pair.

Failure and recovery

The pair is converted without an independent dual-active path. Losing all VSL members can leave both chassis believing they should be active.

Before service, add and verify the release-supported fast-hello, enhanced PAgP, or BFD dual-active design. For fast-hello, the domain enables dual-active detection fast-hello and a dedicated compatible direct interface uses dual-active fast-hello. Exact interface restrictions and recovery behavior follow the chassis guide.