Exam 350-601 topic 1 question 40 discussion

Confirming B and C. When the peer-link comes up between two vPC peers, apart from the vPC roles, the LACP permanent roles are also decided (one peer become the Master, while the other becomes the Slave). An LACP role election occurs if both peers have same role (either master or slave). The system with the lower MAC address wins as master and this election is not governed by the vPC role priority configuration. A re-election causes vPC LACP port-channels to re-initialize, which leads to a possible traffic outage. Before you introduce an already isolated vPC device back into production, check the LACP roles on both boxes. If the same role, disable auto recovery with no auto-recovery under the vPC domain on both peers and reload the isolated device. After reload, the isolated device comes up with the LACP role 'none established' and can be introduced into the vPC without LACP role re-election.

The correct answers are: A. Change the vPC system-priority of the replacement chassis to a higher value than the peer D. Set the vPC MAC address to a lower value than the peer

You cannot Set the vPC MAC address (mac is generated automatically from vpc domain ID to be an unique value) A - (lower system priority number has higher priority on the Primary election. That's why the replaced device should have higher system priority than the active one) C - is enough to disable auto-recovery on the newly introduced switch before the vpc restoration default timer expires and reload it Also another option would be to enable sticky-bit on the active switch, this would make sure the newly introduced switch will never take the active role Correct Answer A and C

B and C

B and C

A. the higher priority value of the replaced to keep it as the slave D. disable the recover timers such that it does not put the ports in a suspended state until the timers expire

I think it is simply B, E You want to make sure that the replaced chassis does not flap the vPCs when the VPC peering is established. To do so, - Configure the replacement chassis with lower priority so it would become slave once booted <= recommend or - Configure system mac address of the new system to be higher (newer) as if the priority is set to be the same, the lower mac address (older system) is the tie breaker and gets to be the master.

B and C are correct. https://www.cisco.com/c/en/us/support/docs/interfaces-modules/nexus-7000-series-supervisor-1-module/119033-technote-nexus-00.html. 1) The system with the lower MAC address wins as master and this election is not governed by the vPC role priority 2) Before you introduce an already isolated vPC device back into production, check the LACP roles on both boxes. If the same role, disable auto recovery with no auto-recovery under the vPC domain on both peers and reload the isolated device. After reload, the isolated device comes up with the LACP role 'none established' and can be introduced into the vPC without LACP role re-election.

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/layer2/503_n2_1/503_n2_1nw/Cisco_n5k_layer2_config_gd_rel_503_N2_1_chapter8.html#concept_5CFDE2E09BCC45C6A976B6CADEFA0D82 LACP uses system-MAC. so answer is B, C

Correct answers are C & D. https://community.cisco.com/t5/networking-documents/vpc-auto-recovery-feature-in-nexus-7000/ta-p/3123651 https://www.cisco.com/c/en/us/support/docs/ios-nx-os-software/nx-os-software/212589-understanding-vpc-election-process.html#anc18

I think it should be B,C, as with higher mac address, it would act as slave for LACP and won't trigger election. https://www.cisco.com/c/en/us/support/docs/interfaces-modules/nexus-7000-series-supervisor-1-module/119033-technote-nexus-00.html