I am studying for CCNA and the book I am using states that

Once configured, the two routers negotiate as to which will be the AVG. As with HSRP, if both come up at the same time, R1 will win, with a priority set to 110 with the glbp 1 priority 110 command versus R2’s default priority of 100. However, if either router comes up before the other, that router goes ahead and takes on the AVG role.

Is this similar to the case that if an OSPF router's RID is changed, it will only take effect after the OSPF process is restarted?

Other GLBP configured routers discover the AVG through hello messages and I assume that the selected AVG's ID will circulate in the Hellos regardless of the GLBP priority of any new routers that just came online.

None of the other sources corroborate this theory and only mention the priority but they do not deny it either.


The document you link, GLBP - Gateway Load Balancing Protocol, also has this as the last paragraph of GLBP Gateway Priority:

By default, the GLBP gateway preemptive scheme is disabled. A backup virtual gateway can become the AVG only if the current AVG fails, regardless of the priorities assigned to the virtual gateways. You can enable the GLBP preemptive scheme using the glbp preempt command. Preemption allows a backup virtual gateway to become the AVG, if the backup virtual gateway is assigned a higher priority than the current AVG.

This is saying the same thing as what you have quoted above.

  • Facepalm. I remember that I read this part but seems like my brain is shutting down... Thanks for pointing it out. – toraritte Nov 26 '15 at 5:57

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