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Patch 89262-08 For AT-8900 Series Switches show igmpsnooping routeraddress 29
Patch 89262-08 for Software Release 2.6.2
C613-10402-00 REV H
Importing BGP routes into OSPF
Introduction With this enhancement you can import routes from BGP into OSPF. OSPF will
then redistribute these routes. This enhancement adds three parameters to the
set ospf command, and modifies the output of the show ospf command. The
new parameters are bgpimport, bgpfilter and bgplimit.
BGP can learn thousands of routes, so it’s important to consider the network
impact of importing these routes. Routing devices in the OSPF domain may
become overloaded if they store too many routes. You can prevent this by
limiting the number of routes that will be imported.
Do not enable the importing of BGP routes into OSPF unless you are sure about
the consequences for the OSPF domain.
Enabling BGP route
import
To enable importing BGP routes into OSPF, use the command:
set ospf bgpimport=on
Limiting the number
of routes
There are two ways to limit the number of BGP routes imported into OSPF.
One way is to specify a maximum number of routes with the command:
set ospf bgplimit=1...300
When the limit is reached, the importing of routes will stop until existing
routes are removed. Because they are BGP routes, actions of BGP control when
the routes disappear.
The other way to limit the imported routes is to configure a routing filter. This
filter is used in conjunction with the bgpfilter parameter in the set ospf
command to control the passing of routing information in and out of the
device. To configure a filter, use the add ip filter command:
add ip filter=filter-number {action=include|exclude}
source=ipadd [smask=ipadd] [entry=entry-number]
Use this filter to limit imported BGP routes with the command:
set ospf bgpfilter=300...399
where the filter number is the previously configured filter.
Take care when configuring the IP filter. If the number of imported routes
reaches the bgplimit parameter, you may not have imported all the routes
specified with the bgpfilter parameter.
Advertising desired
routes
The order in which routes are added is arbitrary. This means that to have
desired BGP routes advertised by OSPF, you must take care setting the entry
number for the route filter with the add ip route command. Assign a low entry
number to a filter used to import preferred BGP routes. Alternatively, set the
bgplimit parameter above the total number of routes that BGP will ever add to
the routing table.