ECS4660-28F_Management Guide-R03

C HAPTER 51 | IP Routing Commands
Border Gateway Protocol (BGPv4)
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Configuration Guidelines
1. Use the bgp confederation identifier command to configures the
identifier for a confederation containing smaller multiple internal
autonomous systems.
2. Use the bgp confederation peer command to add an internal peer
autonomous system to a confederation.
ROUTE SERVERS
Route Servers are used to relay routes received from remote ASes to client
routers, as well as to relay routes between client routers. Clients maintain
BGP sessions only with the assigned route servers. Sessions with more
than one server can be used to provide redundancy and load sharing. All
routes received from a client router are propagated to other clients through
the Route Server. Since all external routes and their attributes are relayed
unmodified between client routers, they acquire the same routing
information as they would via direct peering in a full mesh configuration.
Figure 559: Connections for Route Server
Configuration Guidelines
Use the neighbor route-server-client command to configure this router as a
route server and the specified neighbor as its client.
ROUTE FLAP
DAMPENING
An update message is sent from a BGP speaker to a neighboring speaker
whenever any change to a route occurs. A speaker announcing such a
route is also responsible for any changes, including withdrawal, change in
AS-Path or Next-Hop, to the same neighbor, irrespective of where the
change was learned. In practice this may cause a BGP speaker to announce
a new route, and then almost immediately withdraw or update the route a
Router
Router
Router
Router
Route
Server
Router
eBGP
Speaker
Router
Router
Advertised
Routes
Router
Router
Router
eBGP
Speaker
Advertised
Routes
Route
Server