In VPLS, we need to be able to perform two actions: - L2 forwarding based on MAC (consider there could be local switching, need to perform MAC learning, flooding etc) - Label imposition
Older PFC (forwarding engine on 6500/7600) cannot perform both actions in the same hardware, so another resource is required. PFC would perform the L2 forwarding functions (like a regular L2 switch would do), and the egress linecard would perform the label imposition. Regular LAN linecards do not have forwarding capacity on them (even if they have a DFC), and would require a more advanced line card. These are the different SIP modules or more recently ES20 and ES+ modules (now also supported on 6500...) On 6500, SUP2T can also do VPLS natively, because the new PFC (PFC4) can do all the processing on its own. Arie -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of ying-xiang Sent: Monday, January 09, 2012 17:27 To: [email protected] Subject: [c-nsp] why vpls need some special line cards to support 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? _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
