HP HSR6800 Configuration Manual page 156

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 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
other. After the VC labels are distributed, a VC is set up between the PEs.
Figure 40 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.
•
Route distinguisher—To distinguish CEs with the same CE ID in different VPNs, Kompella
adds an RD before a CE ID. An RD and a CE ID uniquely identify a CE.
•
Route target—Kompella uses the BGP route target attribute (also called "VPN target" attribute)
to identify VPNs to make sure CEs in the same VPN can establish a connection and CEs in
different VPNs cannot.
A PE supports the following types of route target attributes:
Figure 40, the PEs send the VC FEC and VC label in a label mapping message to each
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"VC types."