A Cisco Nexus 2000 Series Fabric Extender is connected to two Cisco Nexus 5000 Series switches via
a vPC link. After both Cisco Nexus 5000 Series switches lose power, only one switch is able to power
back up. At this time, the Cisco Nexus 2000 Series Fabric Extender is not active and the vPC ports are
unavailable to the network.
Which action will get the Cisco Nexus 2000 Series Fabric Extender active when only one Cisco Nexus
5000 Series switch is up and active?
A.
Move the line from the failed Cisco Nexus 5000 Series switch to the switch that is powered on, so
the port channel forms automatically on the switch that is powered on.
B.
Shut down the peer link on the Cisco Nexus 5000 Series switch that is powered on.
C.
Configure reload restore or auto-recovery reload-delay on the Cisco Nexus 5000 Series switch that
is powered on.
D.
Power off and on the Cisco Nexus 2000 Series Fabric Extender so that it can detect only one Cisco
Nexus 5000 Series switch at power up.
Explanation:
The vPC consistency check message is sent by the vPC peer link. The vPC consistency check cannot
be performed when the peer link is lost. When the vPC peer link is lost, the operational secondary
switch suspends all of its vPC member ports while the vPC member ports remain on the operational
primary switch. If the vPC member ports on the primary switch flaps afterwards (for example, when
the switch or server that connects to the vPC primary switch is reloaded), the ports remain down
due to the vPC consistency check and you cannot add or bring up more vPCs.
Beginning with Cisco NX-OS Release 5.0(2)N2(1), the auto-recovery feature brings up the vPC links
when one peer is down. This feature performs two operations:
• If both switches reload, and only one switch boots up, auto-recovery allows that switch to
assume the role of the primary switch. The vPC links come up after a configurable period of time if
the vPC peer-link and the peer-keepalive fail to become operational within that time. If the peer-link
comes up but the peer-keepalive does not come up, both peer switches keep the vPC links down.
This feature is similar to the reload restore feature in Cisco NX-OS Release 5.0(2)N1(1) and earlier
releases. The reload delay period can range from 240 to 3600 seconds.
• When you disable vPCs on a secondary vPC switch because of a peer-link failure and then the
primary vPC switch fails, the secondary switch reenables the vPCs. In this scenario, the vPC waits for
three consecutive keepalive failures before recovering the vPC links.http://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/operations/n5k_vpc_o
ps.html