H3C Technologies H3C S12500-X Series Switches - Manual (Page 214)

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The output interface of a BGP summary route is Null 0 on the originating router. Therefore, a summary
route must not be an optimal route on the originating router. Otherwise, BGP will fail to forward packets
matching the route. If a summarized specific route has the same mask as the summary route, but has a
lower priority, the summary route becomes the optimal route. In this case, you must change the priority
of the summary or the specific route to make the specific route as the optimal route.
581B
Configuring automatic route summarization
Automatic route summarization enables BGP to summarize IGP subnet routes redistributed by the
import-route command so BGP advertises only natural network routes.
To configure automatic route summarization (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
address family view or
BGP-VPN IPv4 unicast
address family view.
address-family ipv4 [ unicast ] N/A
4. Configure automatic route
summarization.
summary automatic
By default, automatic route
summarization is not configured.
582B
Configuring manual route summarization
By configuring manual route summarization, you can summarize both redistributed routes and routes
injected using the network command and determine the mask length for a summary route as needed.
To configure BGP manual route summarization (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
address family view or
BGP-VPN IPv4 unicast
address family view.
address-family ipv4 [ unicast ] N/A