PC ID in "show vpc map" command CISCO ACI 3.1

[kumar.rb@cognizant.com]

Hello - Can anybody help me to know what is the meaning of PC ID in the output of the command "show vpc map". I attached a simple diagram for reference. 

APIC# show vpc map VPC-TO-ROUTER1

virtual port-channel Name  domain  Virtual IP  Peer IP   VPC   Leaf ID,Name  PC Id  Ports

----------------------------  --------  ------------  ---------     ----    --------------  ------  --------

VPC-TO-ROUTER1              172      ******     *****    327    101,LEAF101   po11  eth1/1

VPC-TO-ROUTER1              172      ******     *****    327    101,LEAF102   po5   eth1/1

regards,RB

[Remi Astruc]

Hello,

When you configure a VPC on traditional NX-OS, you explicitly define on each of the VPC members a Port-channel ID and assign it the VPC ID in common.

When you configure a VPC in ACI, that local Port-channel definition is abstracted by the VPC Policy Group creation, but it still occurs under the cover. Each VPC member is automatically assigned a random PC ID. The command show vpc map shows you the relation between the VPC name and the PC.

Remi Astruc

[kumar.rb@cognizant.com]

Thanks Remi for your response - But still i have a question. When we configure a VPC on traditional NX-OS, we configure Channel-group with the same ID and defined a same VPC ID in both the switches that connects the dual homed host. 

1) Is it mandatory requirement to configure the same Channel-group ID (Example, Channel-group  1 in both the nexus switch) for a VPC link? Example of the configuration is shown below is the practice i followed so far.

2) Can i understand ACI is automatically assigning a different PC ID for a same VPC (PC ID 11 and 5  for VPC 327)?

NEXUS 01

interface port-channel1
description SW-R01-01A: [vpc1]
switchport mode trunk
vpc 1

NEXUS 02

interface port-channel1

description SW-R01-01A:  [vpc1]

switchport mode trunk
vpc 1

regards, RB

[Remi Astruc · Accepted solution]

Hello,

We use to do that in NX-OS to be more human-friendly, but that is not a requirement.

Yes, ACI can automatically (randomly) assign a different PC-ID than the VPC ID (which is by the way also random ;-) )

Remi Astruc