| 摘要 |
A destination router label is added to Pseudo Wire encapsulated data packets for crossing a Multiple Protocol Label Switching (MPLS) network. Data arrives at a PW function, which performs PW encapsulation, further adding a PWE control word and a PWE label. The PW function also adds a destination router label (DRL). The DRL is configured at PW creation time with a PW control message (that is, an unsolicited LabelMap message) to a specific edge router. The packet may then be sent to a Traffic Engineering (TE) function, which uses the DRL to make the routing decision for the packet. The routing decision includes adding a PSN tunnel label to replace the DRL label for crossing the transport network. The rest of the processing is conventional PWE3 transport on MPLS; that is, when the packet is received at a second PW function, it removes the PW encapsulations and forwards the packet based on the contents of the PWE label.
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