214
Step Command
Remarks
4.
Enable MED comparison for
routes from different ASs.
compare-different-as-med
By default, this feature is disabled.
To enable MED comparison for routes from different ASs (IPv6):
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP view.
bgp
as-number
N/A
3.
Enter BGP IPv6 unicast
address family view.
address-family ipv6
[
unicast
] N/A
4.
Enable MED comparison for
routes from different ASs.
compare-different-as-med
By default, this feature is disabled.
Enabling MED comparison for routes on a per-AS basis
This task enables BGP to compare the MEDs of routes from an AS.
Figure 56
Route selection based on MED (in an IPv4 network)
As shown in
, Router D learns network 10.0.0.0 from both Router A and Router B. Because
Router B has a smaller router ID, the route learned from Router B is optimal.
Network NextHop MED LocPrf PrefVal Path/Ogn
*>i 10.0.0.0 2.2.2.2 50 0 300e
* i 3.3.3.3 50 0 200e
When Router D learns network 10.0.0.0 from Router C, it compares the route with the optimal route in
its routing table. Because Router C and Router B reside in different ASs, BGP does not compare the MEDs
of the two routes. Router C has a smaller router ID than Router B so the route from Router C becomes
optimal.
Network NextHop MED LocPrf PrefVal Path/Ogn
*>i 10.0.0.0 1.1.1.1 60 0 200e
* i 10.0.0.0 2.2.2.2 50 0 300e
AS 300
AS 100
AS 200
Router A
Router D
Router ID : 3.3.3.3
Router ID : 1.1.1.1
Router C
Eth1/1
1.1.1.1
Eth1/1
3.3.3.3/24
Router B
Router ID : 2.2.2.2
Eth1/1
2.2.2.2/24
AS 400
Router E
10.0.0.0