MPLS Implementation from a Customer Perspective

Answered Question
May 29th, 2009

Our company is planning to migrate all our point-point curcuits to MPLS.

As a customer, I would like to understand more about how the ISP will provide this service? Will they install a router at our site and provide us with an ethernet handoff to our own router?

Is the bandwith scalable to any size we want? Will they accept OSPF from our network? Any documents would be appreciated.

I have this problem too.
0 votes

Well.. it depends which provider you are talking about.. i haven't seen one running OSPF between CE and PE yet.. but from an config standpoint it's possible.

Most of the times they have an BGP peer between your CE and their PE and you have to run both protocols and perform mutual redistribution.

You can specify the bandwidth, but it will be up to the provider what was the link you ordered.

Hope that helps.

I think his question is more related how this setup between his CE router and the ISP would work?

Briefly, in the most of cases you won't be running MPLS over our CE router. Usually, you would have an simple EBGP peers with the provider and in this case the provider is the responsible to route your network over their MPLS backbone.

Does that makes sense?

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Joseph W. Doherty Fri, 05/29/2009 - 16:44

Such questions are best answered by your MPLS provider since they often offer many options and some depend on what's physically available in your service area.

For instance, you might have the option of L2 or L3 MPLS, route peering of your device to a MPLS cloud device or provider managed device on your site (often with different available dynamic routing protocol options), multiple choices of physical connectivity to/from MPLS cloud, etc.

One major difference, MPLS clouds often provide full mesh or multipoint connectivity so it's easy to encounter cloud egress congestion if you have multiple sites send traffic to one site. You may want to find what QoS support, if any, the MPLS provider supports.

lamav Fri, 05/29/2009 - 18:13

David, regarding extending your OSPF domain across the provider's MPLS cloud:

Trying to extend your OSPF domain across the provider's MP-BGP backbone requires the proper deployment of OSPF enhancements, like the OSPF Domain community and the ability to pass the LSA type information of the source route, as well as the OSPF cost/MED, to the BGP process.

In that case, the MP-BGP cloud of the SP is going to have to act as a "superbackbone" and logically sit "above" your Area 0 backbone. The PE routers will have to disguise themselves as OSPF ABR/ASBRs and inject inter-area routes on the other side of the MPLS cloud when it redistributes back to OSPF.

In other words, classic redistribution will not suffice because the intra- and inter-area routes will be reinjected back into your OSPF domain on the other side of the SP cloud as external routes, which can really throw off your routing schema. Take note that external routes will remain external routes after redistribution at the distant end.

If possible, just BGP peer with the provider.

HTH

Victor

Correct Answer

I think his question is more related how this setup between his CE router and the ISP would work?

Briefly, in the most of cases you won't be running MPLS over our CE router. Usually, you would have an simple EBGP peers with the provider and in this case the provider is the responsible to route your network over their MPLS backbone.

Does that makes sense?

davidhuynh5 Tue, 06/02/2009 - 03:19

Thank you. Do most providers take OSPF or do I have to run both EBGP and OSPF?

Also, can I speocify a specific bandwidth requirement (i.e 9mpbs, 12 mbps, etc.)?

Correct Answer

Well.. it depends which provider you are talking about.. i haven't seen one running OSPF between CE and PE yet.. but from an config standpoint it's possible.

Most of the times they have an BGP peer between your CE and their PE and you have to run both protocols and perform mutual redistribution.

You can specify the bandwidth, but it will be up to the provider what was the link you ordered.

Hope that helps.

rakeshsekhar Fri, 03/08/2013 - 10:33

Hi ,

                         May I know how to configure "VRF Route Import Extended Community" in IOS XR ??

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