Maximum LSP on Inter-AS vpnv4/ipv4

[fernando.romao]

Hi Luc

Thank you for your reply, in fact we are in the process of using Option B (ASBR-to-ASBR). We have all the configs in place just did not activate the neighbors pending confirmation. We are using Eng5; I would expect CAM/TFIB to be able to hold these prefixes, I seem to have noticed that the weakest processor can handle up to one million. Yet, it is not written anywhere on these specifics.

Thanks

FR

[Luc De Ghein · Accepted solution]

Hi Fernando,

In MPLS VPN networks, 17000 vpnv4 prefixes is not that much. You can have hundreds of thousand of vpnv4 prefixes.

You did not specifiy which option A,B, C or D you are running. For option A and D, the scalability could become an issue because you'll have many logical links between the ASBRs, one for every VPN shared between the 2 autonomous systems. This is a known limitation factor in these two designs and it is a pain to operate such a model, starting from a certain scale. Each new VPN shared between the 2 autonomous systems will lead to the creation of a new logical link on the ASBRs.

Option B and C do not have this and are hence more scalable and easier to maintain operationally. What inter-as MPLS VPN brings is the concentration of the LSPs on the ASBRs, instead of having them spread over many PE and P routers in a non-inter-as MPLS VPN network. But, 17000 prefixes should be ok on a 12k router.

Thanks,

Luc