VRID Question

  • 0
  • 1
  • Question
  • Updated 2 years ago
  • Answered


Hi - I have a question regarding when to use a single VRID and when to use differnet VRIDs. As I understand it, a VRID designates a virtual router pair - when 2 routers have the same VRID they are able to exchange VRRP messages.

In my example above - If I have CORE A and CORE B in the same buildling with the same 3 VLANs on - should I use a different VRID for each VLAN or the same VRID for all VLANS. Historically we have always used 1 VRID for all vlans across the cores and it has worked as we would expect.

The only reason I ask the question is when configuring ports on the core with multiple VLANs we often get the following warning from the switch;

WARNING : Port <port number> belongs to multiple VLANs with the same VRID

I'm not sure why the switch warns of this - why is this a problem/warning?

Thanks
Photo of Leo

Leo

  • 112 Points 100 badge 2x thumb

Posted 2 years ago

  • 0
  • 1
Photo of OscarK

OscarK, ESE

  • 7,912 Points 5k badge 2x thumb
The VRRP message is a bit misleading. Up till 16.1 you can only use 7 vrid's on a switch, newer versions can use more but there is no need to use difference vrid's on different vlans.
I would just keep the same VRID on all vlans, no problem with that.
Photo of Karthik Mohandoss

Karthik Mohandoss, Employee

  • 5,998 Points 5k badge 2x thumb
Leo,


VRID can be reused in different VLAN's, the warning messages are not seen in latest software versions, i tested it in 22.x and 21.x , what is the EXOS version you have tested this?

Still i would say this could be a cosmetic issue which is not seen in latest EXOS versions.


please let me know if this helps.

I should have refreshed before posting :)
(Edited)
Photo of Leo

Leo

  • 112 Points 100 badge 2x thumb
Thanks Karthik, We're currently using 16.1. We're due to be configuring VVRP sometime next week so I'll keep you posted on if we get the warning in this release. :)
Photo of Henrique

Henrique, Employee

  • 10,302 Points 10k badge 2x thumb
Hi Leo, 

You can define priority based on VRID to select the Master and Backup role between Core A and Core B.

Let's say you have 4 vlans (A1, A2, B1, B2). You can configure the same VRID (let's say "1" for A1 and A2 vlans; and VRID "2" for B1 and B2 vlans).

Then you can set a better priority (higher than 100) to A1 and A2 on Core A and to B1 and B2 to Core A.

Then you would have A1/A2 vlans being routed through Core A and B1/B2 vlans routed through Core B.
Photo of Leo

Leo

  • 112 Points 100 badge 2x thumb
Hi Henrique, Thanks for your reply. So I understand what you're saying there but I have a question. In your example there's no reason why I couldn't have A1, A2, B1, B2 all in the same VRID - say VRID 1 and still use the priority to have the A masters one side and the B masters the other.

Are there any benefits to using different VRIDs other than the VRRP communication traffic being separate?
Photo of Henrique

Henrique, Employee

  • 10,302 Points 10k badge 2x thumb
Hi Leo, I believe the only difference here would be using different "VRRP:VRID_number" MAC addresses and would help for a better troubleshooting insight.