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Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 22 Configuring EtherChannel and Link State Tracking Displaying EtherChannel to a Virtual Switch System
remote switch stores the new active ID and immediately transmits asynchronous PAgP messages with TLVs containing the new active ID. Upon receiving the new active ID from the remote switch, the original active virtual switch detects the dual-active scenario and takes appropriate actions.
Figure 22-1 Enhanced PAgP in VSS Normal Opertaion
Figure 22-2 Enhanced PAgP in VSS Dual-active Scenario
As a remote switch, the Catalyst 4500 series switch supports stateful VSS client. In particular, the ID of the current active virtual switch is synchronized from the active supervisor engine to the redundant supervisor engine of the Catalyst 4500 series switch. This ensures that dual-active detection is not disrupted even when the active supervisor engine switches over to the redundant supervisor engine.
Virtual
Switch A
(active)
Virtual
Switch B
(standby)
Remote switch
(Catalyst 4500 series switch)
Active_ID = A’s MAC
Virtual switch TLV
Active_ID = A’s MAC
Virtual switch TLV
Active_ID = A’s MAC
Remote switch TLV
Active_ID = A’s MAC Remote switch TLV
Active_ID = A’s MAC
VSL
EtherChannel
204283
Remote switch
(Catalyst 4500 series switch)
Active_ID = B’s MAC
Virtual switch TLV
Active_ID = B’s MAC
Remote switch TLV
Active_ID = B’s MAC
Dual-active detected by A
Remote switch TLV
Active_ID = B’s MAC
VSL
204284
Virtual
Switch A
(active)
Virtual
Switch B
(standby)
EtherChannel