R2511-HP MSR Router Series MPLS Configuration Guide(V5)

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2. After the P device receives the packet, it looks up the label forwarding table, and swaps label 300
with label 310.
3. After receiving the packet, PE 2 deletes the label from the packet, and then forwards the packet out
of the bound interface Interface B to CE 2.
Unlike other MPLS L2VPN modes, CCC employs only one level of label to transfer user packets. A static
LSP forwards only packets from the AC bound to the static LSP. Therefore, CCC uses LSPs exclusively. LSPs
used by a CCC connection transfers only CCC connection data. They cannot be used by other
connections or MPLS L3VPN.
SVC MPLS L2VPN
SVC implements MPLS L2VPN by static configuration. It uses two levels of labels to transfer user packets.
The inner label is statically configured on PEs. No signaling protocol is used.
Martini MPLS L2VPN
Martini MPLS L2VPN employs two levels of labels to transfer user packets, and uses LDP as the signaling
protocol to distribute the inner VC label.
To exchange VC labels between PEs, Martini extended LDP by adding the VC FEC. The VC FEC contains
the following information:
• VC type—Encapsulation type of the VC. For more information, see "VC encapsulations types."
• VC
ID—Identifier of a VC on a PE.
The VC type and the VC ID uniquely identify a VC. On a PE, the VC ID uniquely identifies a VC among
the VCs of the same type.
As shown in Figure 20, the P
Es send a VC FEC and VC label mapping to each other. After the VC labels
are distributed, a VC is set up between the PEs.
Figure 20 Label distribution in Martini mode
Kompella MPLS L2VPN
Kompella MPLS L2VPN employs two levels of labels to transfer user packets, and uses BGP as the
signaling protocol to distribute the inner VC label.
Different from other MPLS L2VPN modes, Kompella introduces the concept of VPN. It allows CEs in the
same VPN to establish a connection. CEs in different VPNs cannot establish a connection.
Kompella MPLS L2VPN has the following basic concepts:
• CE ID—Kompella numbers CEs inside a VPN. A CE ID uniquely identifies a CE in a VPN. CEs in
different VPNs can have the same CE ID.