CCNP DC · vPC

Nexus: build a vPC domain to an access switch

SW3 already bundles its two uplinks into Port-channel10 with LACP, one to N1 and one to N2. Without vPC that bundle cannot form across two switches. Turn N1 and N2 into a vPC pair so SW3 sees one partner and forwards on both links.

CCNP Data Center track · Cisco Nexus (NX-OS-style) + Cisco · 6 objectives

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Objectives

The simulator ticks each one as soon as the network meets it.

Enable feature lacp and feature vpc on N1 and N2.
Create vpc domain 10 on both, with the peer-keepalive over mgmt0 (10.255.0.1 ↔ 10.255.0.2, VRF management, the default); give N1 role priority 100 so it becomes primary.
Bundle Ethernet1/1-2 into port-channel1 (LACP), trunk VLAN 10, and make it the vpc peer-link on both switches.
Bundle Ethernet1/3 into port-channel10 (LACP), trunk VLAN 10, and make it vpc 10 on both switches.
show vpc on N1: peer adjacency formed ok, N1 primary, and SW3 bundles both uplinks (Po10 with two P members).
Ping PC2 (192.168.10.20) from PC1.

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Before you start

The peer-link and the keepalive are different things: the peer-link carries data and synchronises the pair, the keepalive is only a heartbeat that tells the peers apart when the peer-link fails. Both port-channels must match on both peers (type-1 parameters such as mode and native VLAN).

Concept

vPC: one port-channel across two Nexus switches

A virtual port-channel lets a downstream switch or server bundle links that end on two different Nexus switches. The two switches form a vPC domain: they synchronise over a peer-link and check each other is alive over a separate peer-keepalive. Toward the access switch they act as one LACP partner, so both uplinks forward and spanning tree blocks nothing.

Concept

EtherChannel / Eth-Trunk with LACP

Link aggregation bundles parallel links into one logical link. Spanning tree then sees a single port, so all links forward at once instead of one being blocked, and traffic moves to the remaining links if one fails.