HP MSR2000/3000/4000 Router Series Layer 3 - IP Routing Command Reference

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Default
Load balancing is not enabled.
Views
BGP IPv4 unicast address family view, BGP-VPN IPv4 unicast address family view, BGP IPv6 unicast
address family view, BGP-VPN IPv6 unicast address family view
Predefined user roles
network-admin
Parameters
number: Specifies the maximum number of BGP ECMP routes for load balancing, in the range of 1 to 8.
When it is set to 1, load balancing is disabled.
Usage guidelines
Unlike IGP, BGP has no explicit metric for making load balancing decision. Instead, it implements load
balancing by modifying route selection rules. If multiple BGP routes destined for a network meet the
following conditions, the device selects the specified number of routes from these routes for load
balancing:
• The routes have the same AS_PATH, ORIGIN, LOCAL_PREF, and MED attributes.
• All the routes are reflected by a route reflector, or none of the routes is reflected by a route reflector.
Examples
# In BGP IPv4 unicast address family view, enable load balancing and specify the maximum number of
BGP ECMP routes used for load balancing as 2.
<Sysname> system-view
[Sysname] bgp 100
[Sysname-bgp] address-family ipv4 unicast
[Sysname-bgp-ipv4] balance 2
# In BGP-VPN IPv6 unicast address family view, enable load balancing and specify the maximum
number of BGP ECMP routes for load balancing as 2.
<Sysname> system-view
[Sysname] bgp 100
[Sysname-bgp] ip vpn-instance vpn1
[Sysname-bgp-vpn1] address-family ipv6 unicast
[Sysname-bgp-ipv6-vpn1] balance 2
bestroute as-path-neglect
Use bestroute as-path-neglect to configure BGP to not consider the AS_PATH during best route selection.
Use undo bestroute as-path-neglect to configure BGP to consider the AS_PATH during best route
selection.
Syntax
bestroute as-path-neglect
undo bestroute as-path-neglect
Default
BGP considers the AS_PATH during best route selection.