Cisco Cisco Nexus 5010 Switch Guida Alla Progettazione
Design Guide
© 2010 Cisco Systems, Inc. All rights reserved. This document is Cisco Public Information.
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vPC Complete Dual-Active Failure (Double Failure)
In case both the peer link and the peer keepalive link get disconnected, the Cisco Nexus switch does not bring down
the vPC, because each Cisco Nexus Switch cannot discriminate between a vPC device reload and a peer-link- plus
peer-keepalive failure. This means that each vPC member port keeps advertising the same LACP ID as before the
dual-active failure.
the vPC, because each Cisco Nexus Switch cannot discriminate between a vPC device reload and a peer-link- plus
peer-keepalive failure. This means that each vPC member port keeps advertising the same LACP ID as before the
dual-active failure.
As described previously, a vPC topology intrinsically protects from loops in case of dual-active scenarios. In the worst
case, there will be duplicate frames. Despite this, as a loop prevention mechanism, each switch starts forwarding
BPDUs with the same BPDU Bridge ID as prior to the vPC dual active failure.
case, there will be duplicate frames. Despite this, as a loop prevention mechanism, each switch starts forwarding
BPDUs with the same BPDU Bridge ID as prior to the vPC dual active failure.
vPC Dual-Active Failure
The following output illustrates the status of the former primary vPC peer:
nexus7k01-vdc2# show vpc br
Legend:
(*) - local vPC is down, forwarding via vPC peer link
vPC domain id : 1
Peer status : peer link is down
vPC keep-alive status : Suspended (Destination IP not reachable)
Configuration consistency status: success
vPC role : primary
The following output illustrates the status of the former secondary vPC peer, now the operational primary:
nexus7k02-vdc2# show vpc br
Legend:
(*) - local vPC is down, forwarding via vPC peer link
vPC domain id : 1
Peer status : peer link is down
vPC keep-alive status : Suspended (Destination IP not reachable)
Configuration consistency status: success
vPC role : secondary, operational primary
vPC Peer link status
---------------------------------------------------------------------
id Port Status Active vLANs
-- ---- ------ --------------------------------------------------
1 Po10 down -
vPC status
----------------------------------------------------------------------
id Port Status Consistency Reason Active vLANs
-- ---- ------ ----------- -------------------------- ------------
51 Po51 up success success 11-14,21-24
,50,60
52 Po52 up success success 11-14,21-24