Learning IOS and JUNOS

The signaling requirements of VPLS: The virtual circuit setup uses the same LDP signaling mechanism defined for point-to-point services. Using a directed LDP session, each provider edge advertises a virtual circuit label mapping that is used as part of the label stack imposed on the Ethernet frames by the ingress provider edge during packet forwarding. The reachability information distributed in a VPLS Cisco VPLS does not require the exchange of reachability (MAC addresses) information via a signaling protocol. This information is learned from the data plane using standard address learning, aging, and filtering mechanisms defined for Ethernet bridging. However, the LDP signaling used for setting up and tearing down the virtual circuits can be used to indicate to a remote provider edge that some or all MAC addresses learned over a virtual circuit need to be withdrawn from the VSI. This mechanism provides a convergence optimization over the normal address aging that would eventual...

Carrier Supporting Carrier Carrier supporting carrier  (CsC) is a two-layer IP VPN solution designed to allow a backbone carrier to use MPLS VPN (or L2TPv3) to carry traffic belonging to customers' carriers that use MPLS VPNs. Before looking at the solution, it is a good idea to understand the problem being solved . An MPLS PE router holds all the routes of all the sites to which it connects. In a normal scenario, although this  number  can be large, the expectation is that an individual VPN would require at most hundreds or perhaps thousands of entries in a VRF. However, if the customer is itself an ISP, carrying routes belonging to their customers, the potential exists to require the backbone PE to carry an impossibly large number of routes. The CsC solution addresses this issue. CsC is based on the observation that the label switched domain of an MPLS VPN network (that is, the backbone network) on...