11-18-2011 10:13 AM - edited 03-04-2019 02:19 PM
Hey All,
I was wondering if someone could help remind me whether or not BGP and / or MPLS LDP peerings have to occur using a / 32 address. If so, why?
Thanks in advance!
David
11-18-2011 10:46 AM
do you mean IP addresses on loopback interfaces? It's not really necessary, you can use just a normal "link-net" address, but BGP and MPLS needs an uniqe router-id, and a loopback IP is normaly used for this.
11-18-2011 02:04 PM
And of course any /32 would require some form of routing (static or other for reachability) as opposed to say using a /30 address on a pt-pt Ethernet link for peering which would be picked up by the local network..
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11-18-2011 03:43 PM
hi David,
you right you need a host route /32 for MP-BGP with MPLS
You need to use a /32 loopback as the router id for LDP. Without this the PHP is happening one hop too early. This causes to recieve an untagged frame instead of a MPLS frame
however for normal eBGP or iBGP you can use any interface with any subnet as long as it is reachable via IGP or directly connected
hope this help
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