[c-nsp] why vpls need some special line cards to support

[Phil Mayers]

On 09/01/12 15:26, ying-xiang wrote:
> i have been confused by this question for a long time and i have been
> looking up some stuff from CCO.but still can not find the
> answer.what's the difference between when a router need to  handle
> encapsulation of L3VPN and L2vpn?anyone who could give the point?

VPLS requires that the device be able to store a layer 2 FDB of the form:

MAC address -> MPLS LSP


Many forwarding engines e.g. 6500 PFC3 cannot support this. Those 
platforms require linecards with "extended" forwarding engines.