Vpls Implementation - HP FlexNetwork 10500 Series Configuration Manual

to create a single Layer 2 VPN, which is referred to as a VPLS instance. Sites in different VPLS
instances cannot communicate with each other at Layer 2.
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VSI—A virtual switch instance provides Layer 2 switching services for a VPLS instance on a PE.
A VSI acts as a virtual switch that has all the functions of a conventional Ethernet switch,
including source MAC address learning, MAC address aging, and flooding. VPLS uses VSIs to
forward Layer 2 data packets in VPLS instances.

VPLS implementation

Creating a PW
PEs use PWs to forward packets among VPN sites. PWs include static PWs, LDP PWs, BGP PWs,
and BGP auto-discovery LDP PWs.
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Static PW
To create a static PW, specify the address of the remote PE, the incoming label, and the
outgoing label.
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LDP PW
To create an LDP PW, specify the address of the remote PE, and use LDP to advertise the
PW-label binding to the remote PE. After the two PEs receive the PW-label binding from each
other, they establish an LDP PW. The FEC type in the LDP message is PWid FEC Element that
includes the PW ID field (FEC 128). The PW ID identifies the PW bound to the PW label.
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BGP PW
To create a BGP PW, configure BGP to advertise label block information to the remote PE.
After the two PEs receive label block information from each other, they use the label block
information to calculate the incoming and outgoing labels and create the BGP PW. A PE also
uses the received label block information to automatically find the remote PE.
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BGP auto-discovery LDP PW
To create a BGP auto-discovery LDP PW, configure BGP to automatically find the remote PE,
and use LDP to advertise the PW-label binding to the remote PE. After the two PEs receive the
PW-label binding from each other, they establish a BGP auto-discovery LDP PW.
The information advertised by BGP includes the ID (for example, LSR ID) and VPLS ID of the
advertising PE. The receiving PE compares the received VPLS ID with its own VPLS ID. If the
two VPLS IDs are identical, the two PEs use LDP to establish a PW. If not, the PEs do not
establish a PW. The FEC type in the LDP message is Generalized PWid FEC Element (FEC
129), which contains the VPLS ID, Source Attachment Individual Identifier (SAII), and Target
Attachment Individual Identifier (TAII). The SAII is the LSR ID of the advertising PE. The TAII
identifies the remote PE and is advertised by the remote PE. VPLS ID+SAII+TAII uniquely
identifies a PW in a VPLS instance.
MAC address learning, aging, and withdrawal
VPLS provides reachability through source MAC learning. A PE maintains a MAC address table for
each VSI.
As shown in
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Learning the source MAC addresses of directly connected sites.
If the source MAC address of a packet from a CE does not exist in the MAC address table, the
PE learns the source MAC address of the AC connected to the CE.
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Learning the source MAC addresses of remote sites connected through PWs.
A VSI regards a PW as a logical Ethernet interface. If the source MAC address of a packet from
a PW does not exist in the MAC address table, the PE learns the source MAC address on the
PW of the VSI.
Figure 98, a PE learns source MAC addresses in the following ways:
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