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Community Member

Change AS-Path

Hello folks,

I'm currently building a MPLS-network for my company, and one of our goals is to reduce the number of internet-connections. There has been a lot of different internet solutions, and we have at least two AS's that needs to live a a few months into the new solution. One of my AS's needs to live in a VRF in the MPLS-network. Problem is that this is not the same AS as the MPLS-network. I am trying to set up a few eBGP-peerings with our Internet peering-partners, but my AS-path looks a bit strange - My AS-path will be like OLD-AS MPLS-AS OLD-AS i, but I would like to advertise only my OLD-AS with theese updates. Anyone got a solution for that?

L@rs

1 ACCEPTED SOLUTION

Accepted Solutions

Re: Change AS-Path

The size of a given network and its service complexity of the servics offered, dictates the solution.

Since you are an insider and aware, you are free to choose from the available options discussed.

All of the discussed options will work.

Best of luck.

HTH-Cheers,

Swaroop

6 REPLIES

Re: Change AS-Path

Till you have your AS migration done, do not run EBGP as your PE-CE protocol. Wha tyou can do is, just run any IGP as your PE-CE and then use simply extend you Old-AS IGP over the MPLS VPN and form a IBGP between your two disparate OLD-AS.

OLD-AS-RTR1__(IBGP-to-RTR2<-IGP->PE<------>PE<-IGP->IBGP-to-RTR1)__OLD-AS-RTR.

HTH-Cheers,

Swaroop

Community Member

Re: Change AS-Path

Thanks,

I'm not sure if that would solve the problem, as I would like to remove my old routers, and let the new PE's do the peering with my ISP's, but what I could do is running a EoMPLS tunnel from each ISP-interface into my datacentre, and leave a router or two there for Internet-peering.. Will that be a good solution?

L@rs

Re: Change AS-Path

EomplS was not suggested because the routing in that case wont be optimal. Since its a P2P layer 2 circuit.

But if you want to use it as a intermediate solution till you migrate out you old setup, and also the end points involved are not more than 2 (Old AS peering points) then you can use the L2VPN soln.

For the migrated new setup as well, again the same thing goes, if you have only 2 points (1 upstream ISP peering point and second point is datacenter) then you can use the l2VPN soln, if more than 2 points then if you be worthwhile to invest more time and reosurces in planning/designing BGP Free Core for you Internet PE's.

HTH-Cheers,

Swaroop

Re: Change AS-Path

Community Member

Re: Change AS-Path

Thanks.. That was a interresting discussion..

I will probably go for the EoMPLS solution until AS-migration is done.. We are talking about three ISP's - one of them located in the datacentre, two in a Telco-site, where we will add a PE or two..

Another discussion we've had - Internet Global or VRF?

-We concluded that we'd do this in the global table - as we are peering with another MPLS-network, and would not like to flood the other network with a vrf carrying 235K routes.. We thought that it would be easier to shutdown the other MPLS-network's peers in the ipv4 family, still activated in the vpnv4 family....

L@rs

Re: Change AS-Path

The size of a given network and its service complexity of the servics offered, dictates the solution.

Since you are an insider and aware, you are free to choose from the available options discussed.

All of the discussed options will work.

Best of luck.

HTH-Cheers,

Swaroop

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