FTOS Configuration Guide for the C-Series - Force10 Networks

• If a route was received from a nonclient peer, reflect the route to all client peers.
• If the route was received from a client peer, reflect the route to all nonclient and all client peers.
To illustrate how these rules affect routing, see Figure 337 and the following steps.Routers B, C, D, E, and
G are members of the same AS - AS100. These routers are also in the same Route Reflection Cluster,
where Router D is the Route Reflector. Router E and H are client peers of Router D; Routers B and C and
nonclient peers of Router D.
Figure 337 Route Reflection Example
{
eBGP Route
Router A Router B
Router E
iBGP Route
1. Router B receives an advertisement from Router A through eBGP. Since the route is learned through
eBGP, Router B advertises it to all its iBGP peers: Routers C and D.
2. Router C receives the advertisement but does not advertise it to any peer because its only other peer is
Router D, an iBGP peer, and Router D has already learned it through iBGP from Router B.
3. Router D does not advertise the route to Router C because Router C is a nonclient peer and the route
advertisement came from Router B who is also a non-client peer.
4. Router D does reflect the advertisement to Routers E and G because they are client peers of Router D.
5. Routers E and G then advertise this iBGP learned route to their eBGP peers Routers F and H.
Confederations
Communities
{
Route Reflector Route Reflector Client Peers
Router D
Router C
iBGP Routes
iBGP Routes
Router G
eBGP Route
{
eBGP Route
Router F
Router H
BGP communities are sets of routes with one or more common attributes. This is a way to assign
common attributes to multiple routes at the same time.
464 Border Gateway Protocol (BGP)