maximum load-balancing eibgp (BGP-VPN instance IPv6 address family view)

Function

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 1, and load balancing is not implemented.

Format

maximum load-balancing eibgp number

maximum load-balancing eibgp number ecmp-nexthop-changed

undo maximum load-balancing eibgp

Parameters

Parameter Description Value
number

Specifies the maximum number of equal-cost EBGP and IBGP routes.

The value is an integer ranging from 1 to 128.

ecmp-nexthop-changed

Configures a BGP device to change the next hop addresses of routes for load balancing to its address only when the device advertises these routes.

-

Views

BGP-VPN instance IPv6 address family view

Default Level

2: Configuration level

Task Name and Operations

Task Name Operations
bgp write

Usage Guidelines

Usage Scenario

The maximum load-balancing eibgp command is used in a VPN where a CE is dual-homed to PEs. When the CE shares one AS with only one of the CEs, you can set the number of EBGP and IBGP routes for load balancing. This allows VPN traffic to be balanced among EBGP and IBGP routes.

NOTE:

If you run the maximum load-balancing eibgp 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 ecmp-nexthop-changed command, the device does not change the next hop addresses of the routes to be advertised to a local address no matter whether the routes are used for load balancing.

In Add-Path scenarios, the next hops of Add-Path routes to be advertised are processed in the same way as that of the optimal route no matter whether the routes are used for load balancing, regardless of whether load balancing is implemented.

After BGP load balancing is configured, BGP routes that meet the following conditions and have the same AS_Path attribute are 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.
  • AS_path lengths are the same.
  • Origin types (IGP, EGP, or Incomplete) are the same.
  • Multi_Exit Discriminator (MED) values are the same.
  • AS_Path attributes are the same.

    Configuring BGP load balancing better utilizes network resources.

    For BGP routes with the same prefix in a routing table:
  • If the optimal route and the routes selected for load balancing are all labeled routes, the number of routes used for load balancing depends on the maximum load-balancing ingress-lsp or maximum load-balancing transit-lsp command configuration.
  • If the optimal route and the routes selected for load balancing are all non-labeled routes, the number of routes used for load balancing depends on the maximum load-balancing eibgp command configuration.

    If BGP labeled routes implement load balancing and the ingress LSP creation criteria are met, ingress LSPs are created for the labeled routes; If BGP labeled routes implement load balancing and the transit LSP creation criteria are met, transit LSPs are created for the labeled routes.

Configuration Impact

If the maximum load-balancing eibgp command is run more than once, the latest configuration overrides the previous one.

Precautions

The maximum load-balancing and the maximum load-balancing eibgp commands are mutually exclusive.

Load balancing cannot be implemented between leaked and non-leaked routes.

Example

# Set the maximum number of EBGP and IBGP routes for load balancing to 3 and configure the device to change the next hop addresses of routes for load balancing to its address only when the device advertises these routes.
<HUAWEI> system-view
[~HUAWEI] ip vpn-instance vpna
[*HUAWEI-vpn-instance-vpna] ipv6-family
[*HUAWEI-vpn-instance-vpna-af-ipv6] quit
[*HUAWEI-vpn-instance-vpna] quit
[*HUAWEI] bgp 100
[*HUAWEI-bgp] ipv6-family vpn-instance vpna
[*HUAWEI-bgp-6-vpna] maximum load-balancing eibgp 3 ecmp-nexthop-changed
# 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] ipv6-family
[*HUAWEI-vpn-instance-vpna-af-ipv6] quit
[*HUAWEI-vpn-instance-vpna] quit
[*HUAWEI] bgp 100
[*HUAWEI-bgp] ipv6-family vpn-instance vpna
[*HUAWEI-bgp-6-vpna] maximum load-balancing eibgp 3
Copyright © Huawei Technologies Co., Ltd.
Copyright © Huawei Technologies Co., Ltd.
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