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 make sure the BGP peer can find the correct next hop.
For example, as shown in Figure 58, Router A and Router B establish an EBGP neighbor 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 58: NEXT_HOP attribute configuration
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 Figure 59, Router A and Router B establish an EBGP 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 59: NEXT_HOP attribute configuration
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):
Step | Command | Remarks |
---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter BGP view or BGP-VPN instance view. |
| N/A |
3. Enter BGP IPv4 unicast address family view or BGP-VPN IPv4 unicast address family view. | address-family ipv4 [ unicast ] | N/A |
4. Specify the router as the next hop for routes sent to a peer or peer group. | peer { group-name | ip-address } next-hop-local | By default, the router sets itself as the next hop for routes sent to an EBGP peer or peer group. However, it does not set itself as the next hop for routes sent to an IBGP peer or peer group. |
To configure the NEXT_HOP attribute (IPv6):
Step | Command | Remarks |
---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter BGP view. | bgp as-number | N/A |
3. Enter BGP IPv6 unicast address family view. | address-family ipv6 [ unicast ] | N/A |
4. Specify the router as the next hop for routes sent to a peer or peer group. | peer { group-name | ipv6-address } next-hop-local | By default, the router sets itself as the next hop for routes sent to an EBGP peer or peer group. However, it does not set itself as the next hop for routes sent to an IBGP peer or peer group. |