Cisco 2960s to Nexus 5K vPC Config

[johnlloyd_13]

hi,

i'll be configuring vpc between a pair of nexus 5Ks to child or access 2960s switches (four of these). the dual trunk or uplinks were already patched on the 2960s to each 5Ks and was asked to implement vpc on switching infrastructure.

this will be my first time to do it and i've already read white papers on vpc and will be doing some labs soon. just want to ask for some tips/recommendations, best practice and gotchas to prevent. thanks in advance!

[Mark Malone]

Hi

theres not much in it heres a sample config off one of my 5k sets , I always keep one side down when bringing up VPC , when one is up I bring up the other Nexus side  , VPC on nexus side and standard PO on 2960 side , can be trunk or access as usual

Nexus A
interface port-channel4
  description VPC for level1access
  no lacp suspend-individual
  switchport access vlan x
  logging event port link-status
  logging event port trunk-status
  vpc 4

interface Ethernet2/8
  description VPC for level1access
  switchport access vlan x
  channel-group 4 mode active
###########################################
Nexus B
interface port-channel4
  description VPC for level1access
  no lacp suspend-individual
  switchport access vlan x
  logging event port link-status
  logging event port trunk-status
  vpc 4

interface Ethernet2/8
  description VPC for level1access
  switchport access vlan x
  channel-group 4 mode active

[Steven Williams]

Well those configurations are not step one if you don't have base vPC configured yet. 

You need to configure peer keep alive and peer link. 

[Mark Malone]

If John needs the actual vpc domain settings between 5ks i can post them no problem its just a smaple config to get the switch working at vpc level between the devices

[johnlloyd_13]

hi all,

sorry late reply. been busy with other projects. i got the base VPC domain and peer-link configured.

i need to verify the VPC trunks to downstream access switches.

can someone verify my script below?

can i configure (is it ideal?) 'spanning-tree port type normal' on nexus' trunk and port-channel interfaces?

can i configure active-active LACP between NK5 and 2960 trunks?

NK5-1

interface Ethernet1/46

  description ### SW03 - G0/23 ###
  switchport mode trunk
  spanning-tree port type normal
  channel-group 103 mode active

interface port-channel103
  description ### VPC SW03 ###
  switchport mode trunk
  spanning-tree port type normal
  vpc 103

----

NK5-2

interface Ethernet1/46

  description ### SW03 - G0/24 ###
  switchport mode trunk
  spanning-tree port type normal
  channel-group 103 mode active

interface port-channel103
  description ### VPC SW03 ###
  switchport mode trunk
  spanning-tree port type normal
  vpc 103

----

SW03

interface G0/23
 description ### NK5-1 Eth 1/46 ###
 switchport mode trunk
 channel-group 103 mode active

interface G0/24
 description ### NK5-2 Eth 1/46 ###
 switchport mode trunk
 channel-group 103 mode active

interface Port-channel103
 description ### VPC - NEXUS ###
 switchport mode trunk

[Yachay]

I would add three additional lines to the port channels on the Nexus switches:

interface port-channel103
  description ### VPC SW03 ###
  switchport mode trunk

  spanning-tree port type normal
  spanning-tree guard root

  storm-control broadcast level 25.00

  storm-control multicast level 25.00

  vpc 103

[johnlloyd_13]

hi,

just a re-visit on this matter.

i'm going to implement this change soon.

i just want to check if nexus vPC and etherchannel config on downstream/access switches causes any downtime, i.e. STP reconverge, L3 IGPs, HSRP (these are on top of head, not sure if there are other).

[luioskaung90]

Hi Johnlloyd,

How was your change ? is it successfully implemented with these configuration ?

[johnlloyd_13]

hi,

yes, i applied the config except for the storm-control.

you'll need to do this in a change window since there will be STP reconvergence/short downtime.

[luioskaung90]

Hi,

Just want to clarify, STP re-convergence/short downtime was occurred on N5K or Catalyst switch ? 

N5K u were using VPC right ? re-convergence time should be within 50 second. 

Btw, thanks for your reply and do appreciate !! Cheers ! 

[luioskaung90]

---

@johnlloyd_13 wrote:

hi,

yes, i applied the config except for the storm-control.

you'll need to do this in a change window since there will be STP reconvergence/short downtime.

---

Hi,

Just want to clarify, STP re-convergence/short downtime was occurred on N5K or Catalyst switch ? 

N5K u were using VPC right ? re-convergence time should be within 50 second. 

Btw, thanks for your reply and do appreciate !! Cheers !