Join 2 layer 2 mpls links of different providers into one single link?

[Tiago Reis]

Hello all,

I’m thinking about contracting 2 different mpls links from different providers in order to connect 4 sites.

I want to contract 2 links in order to have redundancy. So my question is, it’s possible to have something like link aggregation or load balancing between them without using routing, only layer 2, like pass a trunk at that link? I know that at layer 2 level I can have LACP, but between 2 devices… in this case I will have at each site 1 device that I control connected to 2 different devices (ISP devices).

I will need to buy the devices that I will use to connect my lans to mps layers so I can use any available technology J.

Thanks in advance,

Regards

[e.ciollaro]

Hi Tiego,

in my experience it's unusual to do Layer 2 load balancing on MPLS networks, I didn't see any network done in that way. In any case I suggest you to verify with ISP's if they MPLS (I suppose AToM or VPLS) permit LACP or PAgP traffic. If so may it should work but I have any experience like that; I wonder if  using two different networks won't bring to problems for example due to different delay.

Why don't you load balance at Layer 3 ?

enrico

[Richard Burts · Accepted solution]

I question whether it is feasible to connect MPLS from two providers together at layer 2. One of the fundamental principles of MPLS is that the provider is able to guarantee the integrity of your traffic and that your traffic is separated from anyone else's traffic. The provider can achieve that when the only thing passing through the provider network is traffic that originated from your devices. But how can the provider achieve that when traffic is passing through their network that they did not control and that you did not control?

If the provider is to be able to guarantee integrity of the traffic and separation from anyone else traffic it seems the two networks need to remain separate. I can see that working better at layer 3 than I can at layer 2. With layer 3 you can route separately and can track what you sent through each network. It also seems to me that keeping the networks separate would be an advantage if you need to troubleshoot a problem. If one provider is having issues and the other provider is running fine it would be challenging with both providers in a single layer 2 network to determine who has the problem. But with two layer 3 networks it would be easy to identify who has the problem.

HTH

Rick

[Tiago Reis]

Hello all,

Thanks for your replys J.

I totally agree with you, I think I was trying the impossible J.

I will try to re-arrange the architecture of the sites with a layer3 routing with load balancing capability, something  like cisco RV325.

Thanks a lot!

[Richard Burts]

I am glad that my suggestions were helpful. Thank you for using the rating system to mark this question as answered. This will help other readers in the forum to identify discussions that have helpful information.

I agree that layer 3 routing with load balancing will provide redundancy and could effectively use both links.

HTH

Rick