Configuring Signaling Protocols For Vpls; Vpls Routing And Virtual Ports - Juniper EX9200 Features Manual

CHAPTER 3

Configuring Signaling Protocols for VPLS

VPLS Routing and Virtual Ports

Copyright © 2016, Juniper Networks, Inc.
VPLS Routing and Virtual Ports on page 9
BGP Signaling for VPLS PE Routers Overview on page 11
Interoperability Between BGP Signaling and LDP Signaling in VPLS on page 12
BGP Route Reflectors for VPLS on page 14
Configuring Interoperability Between BGP Signaling and LDP Signaling in
VPLS on page 15
Because VPLS carries Ethernet traffic across a service provider network, it must mimic
an Ethernet network in some ways. When a PE router configured with a VPLS routing
instance receives a packet from a CE device, it first determines whether it has the
destination of the VPLS packet in the appropriate routing table. If it does, it forwards the
packet to the appropriate PE router or CE device. If it does not, it broadcasts the packet
to all other PE routers and CE devices that are members of that VPLS routing instance.
In both cases, the CE device receiving the packet must be different from the one sending
the packet.
NOTE: In the VPLS documentation, the term router is used to refer to any
device that provides routing functions.
When a PE router receives a packet from another PE router, it first determines whether
it has the destination of the VPLS packet in the appropriate routing table. If it does, the
PE router either forwards the packet or drops it depending on whether the destination is
a local or remote CE device:
If the destination is a local CE device, the PE router forwards the packet to it.
If the destination is a remote CE device (connected to another PE router), the PE router
discards the packet.
If the PE router cannot determine the destination of the VPLS packet, it floods the packet
to all attached CE devices.
This process is illustrated in Figure 1 on page 10.
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