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

270
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
Examples
# In BGP IPv4 unicast address family view, ignore AS_PATH in route selection.
<Sysname> system-view
[Sysname] bgp 100
[Sysname-bgp] address-family ipv4 unicast
[Sysname-bgp-ipv4] bestroute as-path-neglect
# In BGP-VPN IPv6 unicast address family view, ignore AS_PATH in route selection.
<Sysname> system-view
[Sysname] bgp 100
[Sysname-bgp] ip vpn-instance vpn1
[Sysname-bgp-vpn1] address-family ipv6 unicast
[Sysname-bgp-ipv6-vpn1] bestroute as-path-neglect
bestroute compare-med
Use bestroute compare-med to enable MED comparison for routes on a per-AS basis.
Use undo bestroute compare-med to restore the default.
Syntax
bestroute compare-med
undo bestroute compare-med
Default
MED comparison for routes on a per-AS basis is disabled.
Views
BGP IPv4 unicast address family view, BGP-VPN IPv4 unicast address family view, BGP IPv6 unicast
address family view
Predefined user roles
network-admin
Usage guidelines
By default, BGP does not compare MEDs for routes from the same AS. When a router learns a new route,
it compares the route with the optimal route in its BGP routing table. If the new route is more optimal, it
becomes the optimal route in the BGP routing table. In this way, route learning sequence might affect
optimal route selection.
With the bestroute compare-med command configured, the router puts routes received from the same AS
into a group. The router then selects the route with the lowest MED from the same group, and compares
routes from different groups. This mechanism avoids the above-mentioned problem.