I've got a choice of getting a new WAN connection but I don't fully understand the reasons for choosing a layer2 wan over a layer3 wan, can someone please explain the advantages/disadvantages of each and when to use either?
Thanks in advance,
A L2 WAN means the entire WAN is just a medium with no routing involved. In other words, both endpoints on both ends of the WAN belong to the same IP subnet.
So, a L2 WAN could be seen as that you have the other end device (on the other end of the WAN) as directly connected (logically at L3).
Examples of L2 WAN could be ATM, Frame-Relay, PPP, leased-lined, etc.
A L3 WAN means that there's routing involved in the WAN itself. This means your next-hop will be your WAN device and not the other end of the WAN.
Both ends of the WAN are in different IP subnets.
Examples of L3 WAN could be MPLS L3 VPN.
Hope it helps.