Valid 400-101 Dumps shared by ExamDiscuss.com for Helping Passing 400-101 Exam! ExamDiscuss.com now offer the newest 400-101 exam dumps, the ExamDiscuss.com 400-101 exam questions have been updated and answers have been corrected get the newest ExamDiscuss.com 400-101 dumps with Test Engine here:
Explanation/Reference: Explanation: VPLS uses MPLS labels so an MPLS network is required. VPLS MPLS packets have a two-label stack. The outer label is used for normal MPLS forwarding in the service provider's network. If BGP is used to establish the VPLS, the inner label is allocated by a PE as part of a label block. If LDP is used, the inner label is a virtual circuit ID assigned by LDP when it first established a mesh between the participating PEs. Every PE keeps track of assigned inner label, and associates these with the VPLS instance. Reference: http://en.wikipedia.org/wiki/Virtual_Private_LAN_Service