Bgp Signaling For Vpls Pe Routers Overview - Juniper EX9200 Features Manual

BGP Signaling for VPLS PE Routers Overview

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Copyright © 2016, Juniper Networks, Inc.
NOTE: Under certain circumstances, VPLS provider routers might duplicate
an Internet Control Message Protocol (ICMP) reply from a CE router when a
PE router has to flood an ICMP request because the destination MAC address
has not yet been learned. The duplicate ICMP reply can be triggered when a
CE router with promiscuous mode enabled is connected to a PE router. The
PE router automatically floods the promiscuous mode–enabled CE router,
which then returns the ICMP request to the VPLS provider routers. The VPLS
provider routers consider the ICMP request to be new and flood the request
again, creating a duplicate ping reply.
BGP can autonomously signal pseudowires between the PE routers participating in the
same virtual private LAN service (VPLS) network. As PE routers are added to and removed
from the VPLS network, BGP can signal pseudowires to new PE routers and tear down
old pseudowires to old PE routers. Each PE router only needs to be configured with the
identity of the VPLS routing instance. Each PE router does not need to be configured with
the identities of all of the PE routers that are or might become a part of the VPLS network.
NOTE: In the VPLS documentation, the word router in terms such as PE router
is used to refer to any device that provides routing functions.
When you configure BGP for signaling in a VPLS network, customer sites can be either
single-homed to a single PE router or multihomed to two or more PE routers. Multihoming
provides redundancy for the connection between the customer site and the service
provider's network.
You can either configure all of the PE routers in the VPLS network as a full mesh or you
can use BGP route reflectors. For full mesh configurations, each PE router needs to be
able to create a bidirectional pseudowire to each of the other PE routers participating in
the VPLS network.
VPLS Multihoming Overview on page 61
VPLS Path Selection Process for PE Routers on page 57
Chapter 3: Configuring Signaling Protocols for VPLS
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