HP 6125XLG R2306-HP 6125XLG Blade Switch Layer 3 - IP Routing Configuration Gu - Page 209

Enabling MED comparison for routes from confederation peers

Page 209 highlights

Network *>i 10.0.0.0 * i * i NextHop 2.2.2.2 3.3.3.3 1.1.1.1 MED LocPrf 50 50 60 To enable MED comparison for routes on a per-AS basis (IPv4): PrefVal Path/Ogn 0 300e 0 200e 0 200e Step 1. Enter system view. 2. Enter BGP view or BGP-VPN instance view. 3. Enter BGP IPv4 unicast instance view or BGP-VPN IPv4 unicast instance view. 4. Enable MED comparison for routes on a per-AS basis. Command system-view • Enter BGP view: bgp as-number • Enter BGP-VPN instance view: a. bgp as-number b. ip vpn-instance vpn-instance-name ipv4-family [ unicast ] bestroute compare-med Remarks N/A N/A N/A By default, this feature is disabled. To enable MED comparison for routes on a per-AS basis (IPv6): Step 1. Enter system view. 2. Enter BGP view. 3. Enter BGP IPv6 unicast instance view. 4. Enable MED comparison for routes on a per-AS basis. Command system-view bgp as-number ipv6-family [ unicast ] bestroute compare-med Remarks N/A N/A N/A By default, this feature is disabled. Enabling MED comparison for routes from confederation peers This task enables BGP to compare the MEDs of routes received from confederation peers. However, if a route received from a confederation peer has an AS number that does not belong to the confederation, BGP does not compare the route with other routes. For example, a confederation has three AS numbers 65006, 65007, and 65009. BGP receives three routes from different confederation peers. The AS_PATH attributes of these routes are 65006 65009, 65007 65009, and 65008 65009, and the MED values of them are 2, 3, and 1. Because the third route's AS_PATH attribute contains AS number 65008 that does not belong to the confederation, BGP does not compare it with other routes. As a result, the first route becomes the optimal route. To enable MED comparison for routes from confederation peers (IPv4): Step 1. Enter system view. Command system-view Remarks N/A 198

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198
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
* i
1.1.1.1
60
0
200e
To enable MED comparison for routes on a per-AS basis (IPv4):
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP view or BGP-VPN
instance view.
Enter BGP view:
bgp
as-number
Enter BGP-VPN instance view:
a.
bgp
as-number
b.
ip vpn-instance
vpn-instance-name
N/A
3.
Enter BGP IPv4 unicast
instance view or BGP-VPN
IPv4 unicast instance view.
ipv4-family
[
unicast
]
N/A
4.
Enable MED comparison for
routes on a per-AS basis.
bestroute compare-med
By default, this feature is disabled.
To enable MED comparison for routes on a per-AS basis (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
instance view.
ipv6-family
[
unicast
]
N/A
4.
Enable MED comparison for
routes on a per-AS basis.
bestroute compare-med
By default, this feature is disabled.
Enabling MED comparison for routes from confederation peers
This task enables BGP to compare the MEDs of routes received from confederation peers. However, if a
route received from a confederation peer has an AS number that does not belong to the confederation,
BGP does not compare the route with other routes. For example, a confederation has three AS numbers
65006, 65007, and 65009. BGP receives three routes from different confederation peers. The AS_PATH
attributes of these routes are 65006 65009, 65007 65009, and 65008 65009, and the MED values of
them are 2, 3, and 1. Because the third route's AS_PATH attribute contains AS number 65008 that does
not belong to the confederation, BGP does not compare it with other routes. As a result, the first route
becomes the optimal route.
To enable MED comparison for routes from confederation peers (IPv4):
Step
Command
Remarks
1.
Enter system view.
system-view
N/A