EPC backhaul networks

Sun Jan 30 21:57:30 UTC 2011

Easier to troubleshoot is the main reason but also, you would not put the
MME/S-GW in every segment with the eNodeB anyways, so in the end you'd
really want a L3 routed solution between them.  One of the things I've
seen is the L3 interface for the eNodeB terminates locally on an attached
smaller cell-site router via a /30 and is not part of a larger L2 service
with many eNodeBs in the same broadcast domain.   You can run into scale
issues with L3 as well with a router at every cell site and dynamic
routing, so usually it's some kind of hybrid solution.

Most service providers who provide backhaul services for wireless
providers do so over a L2 or PW over MPLS network. Some of the smaller
ALU, etc. cell site routers have started to support L3VPN so maybe L3VPN
will be a service offering in the future with all-IP EPCs.

Phil 

On 1/30/11 12:02 PM, "Glen Kent" <glen.kent at gmail.com> wrote:

>Hi,
>
>I would like to understand why there is a preference for L3 VPNs over
>L2 VPNs for the EPC backhaul networks? We can use both layer 2 and
>layer 3 VPNs for communication between the eNodeB and the MME or S-GW,
>so why is it that most providers prefer L3 over L2.
>
>Glen
>