GLBP (Gateway Load Balancing Protocol)

Hello Rene!

I have a question, how many virtual forwarders per GLBP group, the GLBP supports?

Hello Fabio.

GLBP supports up to 1024 virtual routers or GLBP groups on each physical interface of a router, and up to 4 virtual forwarders per group.

I hope this has been helpful!


Could you please add some video training for Unit6

19 posts were merged into an existing topic: GLBP (Gateway Load Balancing Protocol)

Hello Rene,

Here I have a question about GLBP interface tracking part.
In that part, GLBP use weighting mechanism but I havn’t see you input the command “glbp 1 load-balancing weighted”.
Does it means for tracking needn’t that command? According my understand the default method is round-robin.
Could you pls give some explanation on that? Thank you.


Hello Simon

The mechanism of GLBP you are referring to is load balancing while the mechanism described in the lesson is tracking. These are two different concepts. Both tracking and load balancing can be implemented using several parameters including weighting.

The load balancing mechanism allows multiple gateways to be used simultaneously thus sharing the load of being a gateway. It is configured using the following command:

glbp group load-balancing [host-dependent | round-robin | weighted]

The load balancing can be configured to function by either host-dependent, round robin or weighted. Weighted here is the method used to configure load balancing.

Tracking on the other hand is a mechanism by which you define WHEN to consider an AVF as unavailable and WHEN it should be considered available again. To configure this, you do it as mentioned in the lesson. Again, weighting is the method that tracking uses to determine if an AVF should be made available/unavailable.

I hope this has been helpful!


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Hello Rene
can you please share the full config of that session?

Thanks million

Hi Fahad,

I just updated this article with a new topology picture and added the final configurations.


Hello @lagapides,

I quite don’t understand the usefulness of glbp name command
Can you clarify?


on the diagram you use .254 as the virtual and H1 is set to use gw of
yet SW1 and SW2 are set to use as the VIP.

Hello Trust

According to most Cisco documentation it is one of the necessary steps in order to have the redundancy function. If it was optional, it usually states it as optional in the configuration examples, however it does not. Having said that, the name designation is not necessary and GLBP works fine without it. I believe it is just a label that you can add to make your configuration easier to understand. I’ve read that the high availability group name is referenced in Stateful NAT as well, so it may have some uses that are beyond just labelling.

I hope this has been helpful!



I couldn’t locate the .254 on GLBP lesson. I think you confused it with the HSRP lesson where the virtual GW is .254

Second picture the big green router

I thought you were talking about configuration wise.

The switches are wrong as have a vip of .3 not 254

Hello Dion

Thanks for pointing that out, I’ll let Rene know…


Thanks Dion, just fixed it!



A small remark: I believe at the end of the chapter, for SW1 configuration, the interface GigabitEthernet0/2 should be a routed port (no switchport).

Thank you,

Hello Staut

Yes, you are correct. I’ll let Rene know…



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That’s right, thanks Stefanita. Just fixed it.


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