2 BGP peers terminating on one router

Answered Question
Apr 22nd, 2008
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I just have a quick question here, I have 2 BGP connections a primary and backup terminating on the one router. In the pass the way I know how to deal with it is put them in a vlan in the terminating router and use the vlan to peer. That way if the primary goes down I still have connection via the back up. Now the person I'm working with informs me that since he created 2 /30 I don't need to run a vlan....how else do I get this to work? I've tried explaining to him but he will not change the 2 /30 into one /29 so I can to a vlan between the primary and secondary. If I had another router then I would put primary on one and secondary on the other. Thank you in advance

Correct Answer by cisco_lad2004 about 9 years 2 months ago

a /29 and one VLAN ID is valid. personally, I prefer 2 VLAN IDs and 2 subnets.

number of IPs used is same for 2 x /30 or 1 x /29. but U get out of it is protection against human error, when VLAN is removed form trunk for example or interface VLAN clean up by error.


HTH

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prakapat Tue, 04/22/2008 - 05:57
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I will suggest to use loopbacks to create sessions


That will help you in so many ways

wgranada1 Tue, 04/22/2008 - 06:04
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So what you are saying is that it is possible to terminate 2 BGP connecitons, a primary and back up on one router using the loopback interface? please show me how or where I can read up on this.

cisco_lad2004 Tue, 04/22/2008 - 06:18
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If u are relying on VLANs to give u some sort of redundancy, u can simply use 2 VLANs.

each VLAN ID terminated as an VLAN interface and using its own subnet /30.


HTH


Sam

wgranada1 Tue, 04/22/2008 - 07:01
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actually I was making the 2 interfaces that the BGP peers where coming into my router into one vlan and using the vlan to do the peering. Just wondering if there was another way to do this. I'm told I can do it via loopback address. I'm trying to find information on how to do it that way

Correct Answer
cisco_lad2004 Tue, 04/22/2008 - 08:40
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a /29 and one VLAN ID is valid. personally, I prefer 2 VLAN IDs and 2 subnets.

number of IPs used is same for 2 x /30 or 1 x /29. but U get out of it is protection against human error, when VLAN is removed form trunk for example or interface VLAN clean up by error.


HTH

wgranada1 Tue, 04/22/2008 - 10:04
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ok thanks for the info I will go with 2X/30

route instead...thank you for the input on this!!!

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