Mpls L2Vpn Network Models - HP MSR2000 Configuration Manual

label block is the sum of the LRs of all previously assigned label blocks. For example, if the LR
and LO of the first label block are 10 and 0, the LO of the second label block is 10. If the LR of
the second label block is 20, the LO of the third label block is 30.
A label block with LB, LO, and LR as 1000, 10, and 5, respectively, is represented as
1000/10/5.
For example, a VPN has 10 sites, and a PE assigns the first label block LB1/0/10 to the VPN.
When another 15 sites are added, the PE keeps the first label block and assigns the second label
block LB2/10/15 to extend the network. LB1 and LB2 are the initial label values that are randomly
selected by the PE.
Route target—PEs use the BGP route target attribute (also called VPN target attribute) to manage
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BGP L2VPN information advertisement. PEs support the following types of route target attributes:
Export target attribute—When a PE sends L2VPN information to the peer PE in a BGP update
message, it sets the route target attribute in the update message to an export target. L2VPN
information includes the site ID, RD, and label block.
Import target attribute—When a PE receives an update message from the peer PE, it checks the
route target attribute in the update message. If the route target value matches an import target,
the PE accepts the L2VPN information in the update message.
Route target attributes determine from which PEs a PE can receive L2VPN information.

MPLS L2VPN network models

MPLS L2VPN network models include the remote connection and local connection models.
Remote connection model
As shown in
Figure 89 Remote connection model
Local connection model
As shown in
the PE.
Figure 89, this model connects two CEs through a PW on an MPLS or IP backbone.
Figure 90, this model connects two CEs to the same PE so the CEs can communicate through
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