R2511-HP MSR Router Series Layer 3 - IP Routing Command Reference(V5)

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Usage guidelines
Use this command to affect IPv6 BGP route selection.
Examples
# Two devices A and B in the same AS are connected to another AS. Change the local preference of B
from default value 100 to 180, making the route passing B preferred.
<Sysname> system-view
[Sysname] bgp 100
[Sysname-bgp] ipv6-family
[Sysname-bgp-af-ipv6] default local-preference 180
default med (IPv6 address family view/IPv6 BGP-VPN instance
view)
Use default med to specify the default MED value.
Use undo default med to restore the default.
Syntax
default med med-value
undo default med
Default
The default med-value is 0.
Views
IPv6 address family view, IPv6 BGP-VPN instance view
Default command level
2: System level
Parameters
med-value: Specifies the MED value in the range of 0 to 4294967295.
Usage guidelines
The multi-exit discriminator (MED) is an external metric of a route. Different from local preference, MED
is exchanged between ASs and will stay in the AS once it enters the AS. The route with a lower MED is
preferred. When a router running BGP obtains several routes with the identical destination and different
next-hops from various external peers, it will select the best route depending on the MED value. In the
case that all other conditions are the same, the system first selects the route with the smaller MED value
as the best route for the autonomous system.
Examples
# Devices A and B belong to AS 100 and device C belongs to AS 200. C is the peer of A and B.
Configure the MED of A as 25 to make C select the path from B.
<Sysname> system-view
[Sysname] bgp 100
[Sysname-bgp] ipv6-family
[Sysname-bgp-af-ipv6] default med 25