On Jan 30, 2011, at 10:09 AM, Mikael Abrahamsson wrote: > On Sun, 30 Jan 2011, Glen Kent wrote: > >> 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. > > Becuase the lessons learnt in the last 30 years or so of networking is that > large L2 domains are considered harmful. If you subnet them down in different > vlans, it means for every new vlan you need to configure something on the > MME/SGW. > > It's just easier and safer to break it down into smaller L3 domains that you > route between. > It's also easier to troubleshoot when something goes boom.
Owen
