In an L3VPN, how does a PE initially forward a packet it receives from a CE through the service provider network?

The correct answer is C. by binding it with a label that it receives from the destination PE. In an MPLS L3VPN, each PE learns per-prefix VPN labels via MP-BGP from the remote PE. When a CE’s packet arrives, the local PE looks up the destination in its VRF, pushes the VPN label it learned from that remote PE, and then pushes (or swaps) any transport/LDP label to steer the

Layer 3 VPNs

Question

Options

Aby binding it with a label that it receives from the destination CE
Bby binding it with a route target export assigned by the network administrator
Cby binding it with a label that it receives from the destination PE
Dby binding it with a route target import assigned by the network administrator

How the community answered

(31 responses)

A
6% (2)
B
3% (1)
C
90% (28)

Explanation

In an MPLS L3VPN, each PE learns per-prefix VPN labels via MP-BGP from the remote PE. When a CE’s packet arrives, the local PE looks up the destination in its VRF, pushes the VPN label it learned from that remote PE, and then pushes (or swaps) any transport/LDP label to steer the packet through the SP core.

Topics

#L3VPN#MPLS label#PE forwarding#VPN label binding

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