H-Vpls Implementation - HP 12500 Series Configuration Manual

tunnel label into the packet before sending the packet out. If the packet contains no service delimiter,
the PE adds the VLAN tag expected by the peer PE or a null tag, and then a PW label and a tunnel
label into the packet before sending the packet out. For a packet to be sent downstream, the PE
rewrites, removes, or retains the service delimiter depending on your configuration.
According to the protocol, the packet encapsulation type of a PW is VLAN by default.

H-VPLS implementation

Hierarchy of VPLS (H-VPLS) can extend the VPLS access range of a service provider and reduce costs.
H-VPLS access has the following advantages:
• H-VPLS has lower requirements on the multi-tenant unit switch (MTU-s). It has distinct hierarchies
which fulfill definite tasks.
H-VPLS reduces the logical complexity of the fully meshed network consisting of PEs and the
•
configuration complexity.
The H-VPLS access modes include LSP access and QinQ access.
H-VPLS with LSP access
Figure 30 H-VPLS with LSP access
As shown in
U-PW with NPE 1. It does not establish virtual links with any other peers.
Data forwarding in H-VPLS with LSP access is as follows:
Upon receiving a packet from a CE, UPE tags the packet with the MPLS label for the U-PW, namely
•
"the multiplex distinguishing flag", and then sends the packet to NPE 1.
• When receiving the packet, NPE 1 determines which VSI the packet belongs to by the label and,
based on the destination MAC address of the packet, tags the packet with the multiplex
distinguishing flag for the N-PW, and forwards the packet.
Upon receiving the packet from the N-PW, NPE 1 tags the packet with the multiplex distinguishing
•
flag for the U-PW and sends the packet to UPE, which forwards the packet to the CE.
For packets to be exchanged between CE 1 and CE 2, UPE can forward them directly without NPE 1
because it holds the bridging function by itself. For the first packet with an unknown destination MAC
address or a broadcast packet, UPE broadcasts the packet to CE 2 through the bridging function and, at
the same time, forwards it through U-PW to NPE 1, which replicates the packet and sends a copy to each
peer CE.
Figure 30, UPE functions as the convergence device MTU-s and establishes only a virtual link
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