Configuring The Next_Hop Attribute - HP FlexFabric 12900E Series Configuration Manual

Configuring the NEXT_HOP attribute

By default, a BGP router does not set itself as the next hop for routes advertised to an IBGP peer or
peer group. In some cases, however, you must configure the advertising router as the next hop to
ensure that the BGP peer can find the correct next hop.
For example, as shown in
relationship, and Router B and Router C establish an IBGP neighbor relationship. If Router C has no
route destined for IP address 1.1.1.1/24, you must configure Router B to set itself 3.1.1.1/24 as the
next hop for the network 2.1.1.1/24 advertised to Router C.
Figure 60 NEXT_HOP attribute configuration
AS 100
2.1.1.1/24
If a BGP router has two peers on a broadcast network, it does not set itself as the next hop for routes
sent to an EBGP peer by default. As shown in
neighbor relationship, and Router B and Router C establish an IBGP neighbor relationship. They are
on the same broadcast network 1.1.1.0/24. When Router B sends EBGP routes to Router A, it does
not set itself as the next hop by default. However, you can configure Router B to set it (1.1.1.2/24) as
the next hop for routes sent to Router A by using the peer next-hop-local command as needed.
Figure 61 NEXT_HOP attribute configuration
AS 100
Router A
IMPORTANT:
If you have configured BGP load balancing, the router sets itself as the next hop for routes sent to an
IBGP peer or peer group regardless of whether the peer next-hop-local command is configured.
To configure the NEXT_HOP attribute (IPv4 unicast/multicast address family):
Step
1. Enter system view.
Figure
1.1.1.2/24
1.1.1.1/24
EBGP
Router A
1.1.1.2/24
1.1.1.1/24
1.1.1.3/24
60, Router A and Router B establish an EBGP neighbor
3.1.1.1/24 3.1.1.2/24
IBGP
Router B
Figure 61, Router A and Router B establish an EBGP
Router B
AS 200
Router C
Command
system-view
248
AS 200
Router C
Remarks
N/A