VPLS - Which protocol, BGP, OSPF, EIGRP

[dinesh2001]

Hi Community,

I am trying to figure out which protocol to use on a flat layer 2 VPLS.

We have a flat layer 2 to connect 10 offices and some other point to point links to connect to other offices. We currently use EIGRP but going forward we want to control the routnig and the path the traffic takes. I was planning on using BGP to peer between the offices using a hub and spoke topology, instead of a full mesh. I know OSFP is better for a layer 2 VPLS as it alows the full lan to be used effectively.

Can anyone suggest why we shouldn't use BGP on a VPLS from a provider?

Regards

D.

[Vaibhava Varma]

Hi Dinesh

In my personal opinion using BGP in a LAN environment will not provide any benefit as it will add to the BGP Session overhead per LAN Node owing to the Full Mesh requirement which is definitely not scalable.OSPF as an IGP is good choice to be run on the LAN in broadcast Mode which will help keep optmial design using DR/BDR.As far as the Routing Control is concerned BGP should be used for external traffic outside OSPF domain and mutually controlled redistribution between the external Routing Protocol and OSPF should be used.

But if we intend to use Hub and Spoke Topology using P2MP Broadcast Ethernet ie VPLS I think this will not be possible to achieve in OSPF Broadcast Mode neither in BGP using IBGP in Hub and Spoke Fashion among the sites because of BGP Split-Horizon Rule nor using dedicated EBGP Sessions between Hub and Spokes because of 3rd Party Next-Hop feature . So in this scenario of using VPLS for any to any communication in L2 Mode between the sites and then considering Hub and Spoke topology will not be possible to achieve either in OSPF or using BGP and also it defies the basic VPLS connectivity taken to connect the diffent sites in P2MP mode.

This is my personal take on this scenario and hope this helps you something in your design considerations.

Regards

Varma

[dinesh2001]

Hi Vaibhava,

Many thanks for your reply, I have been thinking about your suggestions all week. I realized that OSPF or EIGRP would be best to take advantage of the layer 2 any to any feature of VPLS. However, this VPLS structure I am using may be replaced by point to point circuits between key sites. This therefore makes me believe that if I use eBGP between potential HUBs and then the spokes eBGP peer of these Hubs, it will be easier to migrate from VPLS to a point to point network. Do you think there are any issues with running BGP on VPLS like this?

Regards

Dinesh

[Vaibhava Varma]

Hi Dinesh

BGP is the most preffered choice of RP to be used when it comes to Route Manipulation and it will also be easy to achieve Hub and Spoke Topology in my point of view when we have P2P connections.

Regards

Varma

[smitesh kharecha]

Hi,

I assume that your need is traffic engineering.

My recommendation will be OSPF.

Regards,

Smitesh