The maximum load-balancing eibgp command configures the maximum number of EBGP and IBGP routes for load balancing.
The undo maximum load-balancing eibgp command deletes the configured maximum number of EBGP and IBGP routes for load balancing.
By default, the maximum number of EBGP and IBGP routes for load balancing is not configured.
maximum load-balancing eibgp number [ ecmp-nexthop-changed ]
undo maximum load-balancing eibgp
| Parameter | Description | Value |
|---|---|---|
| number | Specifies the maximum number of equal-cost EBGP and IBGP routes. | The value is an integer that ranges from 1 to 8 on the S5720I-SI, S5720S-SI, S5720-SI, S5735-S, S5735S-S, S5735-S-I, S5730S-EI, S5730-SI, S6720S-SI, or S6720-SI. The value ranges from 1 to 16 on the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, or S6730S-S. |
| ecmp-nexthop-changed | Configures a BGP device to change the next-hop addresses of only the routes that participate in load balancing to its address. | - |
Usage Scenario
The maximum load-balancing eibgp command is used in a VPN where a CE is dual-homed to two PEs. When the CE and one PE belong to an AS and the CE and the other PE belong to a different AS, you can set the number of EBGP and IBGP routes to be used for load balancing. This allows VPN traffic to be balanced among EBGP and IBGP routes.
After BGP load balancing is configured, BGP routes that meet the following conditions and have the same AS_Path attribute will become equal-cost routes and implement load balancing:
PrefVal values are the same.
Local_Pref attributes are the same.
All BGP routes are summarized or non-summarized routes.
Lengths of the AS_path attributes are the same.
Origin types (IGP, EGP, or Incomplete) are the same.
Multi_Exit Discriminator (MED) values are the same.
Protocol priorities are the same. By default, EBGP and IBGP routes have the same protocol priority (255). If the EBGP or IBGP route protocol priority is changed using a route-policy, load balancing cannot be implemented.
Load balancing cannot be implemented between black-hole routes and non-black-hole routes.
Load balancing cannot be implemented between labeled routes and non-labeled routes.
Load balancing cannot be implemented between local routes and non-local routes.
Configuring BGP load balancing better utilizes network resources.
If you run the maximum load-balancing eibgp number command, the device changes the next-hop addresses of the routes to be advertised to a local address no matter whether the routes are used for load balancing. However, in RR or BGP confederation scenarios, the device does not change the next-hop addresses of non-local routes to be advertised to a local address.
If you run the maximum load-balancing eibgp number ecmp-nexthop-changed command, the device changes the next-hop addresses of the routes to be advertised to a local address only when the routes are used for load balancing.
Configuration Impact
If the maximum load-balancing eibgp command is run for multiple times, the latest configuration overrides the previous one.
Load balancing cannot be implemented between crossed and non-crossed routes.
# Set the maximum number of EBGP and IBGP routes for load balancing to 3.
<HUAWEI> system-view [HUAWEI] ip vpn-instance vpna [HUAWEI-vpn-instance-vpna] route-distinguisher 100:1 [HUAWEI-vpn-instance-vpna-af-ipv4] quit [HUAWEI-vpn-instance-vpna] quit [HUAWEI] bgp 100 [HUAWEI-bgp] ipv4-family vpn-instance vpna [HUAWEI-bgp-vpna] maximum load-balancing eibgp 3