R21xx-HP FlexFabric 11900 MPLS Configuration Guide

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Multi-segment PW

A multi-segment PW comprises multiple concatenated static or dynamic PWs. Creating two PWs for a

cross-connect on a PE can concatenate the two PWs. Upon receiving a packet from one PW, the PE

removes the tunnel ID and PW label of the packet, adds the PW label of the other PW, and forwards the

packet over the public tunnel.

As shown in Figure 62, y

ou can create a multi-segment PW between PE 1 and PE 4 by concatenating PW

1 and PW 2 on PE 2, and PW 2 and PW 3 on PE 3.

Figure 62 Multi-segment PW

Multi-segment PWs include intra-domain multi-segment PWs and inter-domain multi-segment PWs.

Intra-domain multi-segment PW

An intra-domain multi-segment PW comprises concatenated PWs within an AS. You can create an

intra-domain multi-segment PW between two PEs that have no public tunnel to each other.

As shown in Figure 63, ther

e is no public tunnel between PE 1 and PE 4 but there is a pubic tunnel

between PE1 and PE 2 and a public tunnel between PE 2 and PE 4. By creating a PW between PE1 and

PE 2 (PW1) and a PW between PE 2 and PE 4 (PW2) and then concatenating the two PWs on PE 2, you

can create an intra-domain multi-segment PW between PE 1 and PE 4.

Intra-domain multi-segment PWs can fully unitize existing public tunnels to reduce end-to-end public

tunnels.

CE 1

PE 1

PE 4

PE 2

PE 3

PW 1

CE 2

PW 2

MPLS or IP backbone