sh glbp [brief]

Hi there,

is there anyone who can explain the output of the command in the subject? I don't know why it looks not consistent across the memebers partecipating in the GLBP group.

Especially the state column: listen, active and STANDBY.

I understand somehow that active refers to the IP address that is active in the router where the command is performed and listen means that such router is listening to that neighbour but I cannot understand why on the standby router I do have the label standby for what is actually the AVG,

Also I don't know why in a router that is not neither the AVG nor the standby VG I canno differentiate who's the active and who's the standby VG.

If you have dealt with GLBP or if you would share your ideas on it with me it will be appreciated a lot.

Thanks!

Alex

Reply to
alex
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Hi Alex

I used to have to worry about this. Perhaps you can post the output you are looking at so we all can see.

Rgds, Martin

Reply to
Martin Gallagher

Unfortunately my dynamips crashed but I can refer to this link

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from where I picked the following (sorry is not formatted with courier character):

R2#sh glbp brief Interface Grp Fwd Pri State Address Active router Standby route Fa1/0 10 ? 100 Standby 10.20.20.1 10.20.20.3 local Fa1/0 10 1 7 Listen 0007.b400.0a01 10.20.20.3 - Fa1/0 10 2 7 Active 0007.b400.0a02 local - Fa1/0 10 3 7 Listen 0007.b400.0a03 10.20.20.4 -

Anyway I gave myself an explanation and the conclusion I came to is that the first line is completely not linked to the remaining ones, meaning the way you read it is different from how you read the rest of the output.

This way from the 2nd onwards the output is more coherent.

I don't know if you had the same difficulty in reading this output but please share your thoughts.

Thanks,

Alex

Reply to
alex

Hello Alex,

Yes. There are two diffrent roles in GLBP, Virtual Gateway (VG) and Virtual Forwarder (VF).

VG is like in HSRP and the first line descibes the VG information:

This router is the Standby router. The Virtual IP addres is 10.20.20.1 The Active router is 10.20.20.3

In HSRP only one router forwards traffic. In GLBP you can have up 4 forwarders and lines 2-4 in the output describe the Virtual forwarders:

There are three forwarders. 10.20.20.3 using MAC address 0007.b400.0a01 10.20.20.4 using MAC address 0007.b400.0a03 This router using MAC address 0007.b400.0a02

REF: ==== GLBP - Gateway Load Balancing Protocol

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Reply to
Martin Gallagher

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