3Com Switch 8800 Advanced Software V5 Configuration Guide

Controlling Route Distribution and Reception 437
n
■ The ORIGIN attribute of routes redistributed using the import-route
command is Incomplete.
■ The ORIGIN attribute of networks advertised into the BGP routing table with
the network command is IGP and these networks must exist in the local IP
routing table. Using a routing policy makes routes control more flexible.
Configuring BGP Route
Summarization
To reduce the routing table size on medium and large BGP networks, you need to
configure route summarization on peers. BGP supports two summarization types:
automatic and manual.
■ Automatic summarization: Summarizes redistributed IGP subnets. With the
feature configured, BGP advertises only summary natural networks rather than
subnets. The default route and routes imported using the network command
can not be summarized.
■ Manual summarization: Summarizes BGP local routes. The manual summary
routes have higher priority than automatic ones.
To configure BGP route summarization, use the following commands:
Advertising a Default
Route to a Peer or Peer
Group
To advertise a default route to a peer or peer group, use the following commands:
n
With the peer default-route-advertise command executed, the router sends a
default route with the next hop being itself to the specified peer/peer group,
regardless of whether the default route is available in the routing table.
To do... Use the command... Remarks
Enter system view system-view -
Enter BGP view bgp as-number -
Configure
BGP route
summarizatio
n
Configure
automatic
route
summarizatio
n
summary automatic Required
No route summarization is
configured by default
Choose either as needed; if
both are configured, the
manual route summarization
takes effect.
Configure
manual route
summarizatio
n
aggregate ip-address { mask
| mask-length } [ as-set |
attribute-policy
route-policy-name |
detail-suppressed |
origin-policy
route-policy-name |
suppress-policy
route-policy-name ]*
To do... Use the command... Remarks
Enter system view system-view -
Enter BGP view bgp as-number -
Advertise a default route to a
peer or peer group
peer { group-name |
ip-address }
default-route-advertise [
route-policy
route-policy-name ]
Required
Not advertised by default