Install guide

Software Version 2.7.5 49
Software Version 2.7.5
C613-10454-00 REV A
Configuring
automatic
summarising
If you want to import routes from RIB into BGP and automatically summarise
them into networks, use the following procedure. Instead of importing routes
to subnets within each network, BGP then imports and advertises the route to
the summary network. It specifies this router or switch as the next hop for the
summary route.
Examples of
automatic
summarising
The following table uses the example of the static routes 192.168.1.64/26 and
192.168.1.128/26 to show what BGP advertises with different combinations of
import and network entries, with and without automatic summarising.
Step Command Action
1 add bgp import
={interface|ospf|rip|static}
[routemap=routemap]
or
add bgp network=prefix[/0..32]
[mask=mask] [routemap=routemap]
Turn on importing for the required
routing source or network.
Note that automatic summarising
applies to all routes that BGP imports. If
you configure multiple import or
network entries, BGP summarises routes
from all of them.
2 enable bgp autosummary Enable automatic summarising.
3 show bgp route Check that BGP has imported and
summarised the desired networks.
Automatic summarising? Commands BGP advertises
No add bgp import=static
add ip route=192.168.1.64/26 nexthop=ipadd
add ip route=192.168.1.128/26 nexthop=ipadd
Routes to 192.168.1.64/26 and
192.168.1.128/26.
add bgp network=192.168.1.0/24
add ip route=192.168.1.64/26 nexthop=ipadd
add ip route=192.168.1.128/26 nexthop=ipadd
Nothing. BGP does not advertise a route
to 192.168.1.0/24 unless it can find one
in the router or switch’s RIB.
add bgp import=static
add bgp network=192.168.1.0/24
add ip route=192.168.1.64/26 nexthop=ipadd
add ip route=192.168.1.128/26 nexthop=ipadd
Routes to 192.168.1.64/26 and
192.168.1.128/26. BGP does not
advertise a route to 192.168.1.0/24
unless it can find one in the router or
switch’s RIB.
Yes add bgp import=static
enable bgp autosummary
add ip route=192.168.1.64/26 nexthop=ipadd
add ip route=192.168.1.128/26 nexthop=ipadd
A single route to 192.168.1.0/24 with
nexthop=0.0.0.0. Automatic
summarising replaces the two subnet
entries in the BGP routing table with this
one entry.
add bgp network=192.168.1.0/24
enable bgp autosummary
add ip route=192.168.1.64/26 nexthop=ipadd
add ip route=192.168.1.128/26 nexthop=ipadd
A single route to 192.168.1.0/24 with
nexthop=0.0.0.0. BGP advertises
192.168.1.0/24 because it finds a route
to that network in the router or switch’s
RIB.
add bgp import=static
add bgp network=192.168.1.0/24
enable bgp autosummary
add ip route=192.168.1.64/26 nexthop=ipadd
add ip route=192.168.1.128/26 nexthop=ipadd
A single route to 192.168.1.0/24 with
nexthop=0.0.0.0. You do not need to
specify both import and network
entries.