Allied Telesis Patch 89262-08 manual Importing BGP routes into Ospf

Page 29

Patch 89262-08 For AT-8900 Series Switches

show igmpsnooping routeraddress

29

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 To enable importing BGP routes into OSPF, use the command:

import

set ospf bgpimport=on

Limiting the number There are two ways to limit the number of BGP routes imported into OSPF. of routes 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=includeexclude} 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 The order in which routes are added is arbitrary. This means that to have routes 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.

Patch 89262-08 for Software Release 2.6.2 C613-10402-00 REV H

Page 28 Page 30
Image 29
Page 28 Page 30
Contents Introduction Patch For AT-8900 Series SwitchesPCR Module IP6 Level FeaturesPCR 40573 Module LOG Level PCR 40591 Module Swmx LevelPCR 40601 Module Swmx Level PCR 40596 Module Swmx LevelPCR Module IPG Level PCR 40603 Module SWI, Swmx LevelPCR Module BGP Level Patch file details are listed in TablePCR Module BGP, IGP Level PCR Module OSPF, IPG LevelPCR Module STP Level PCR 40460 Module Swmx LevelPCR 40496 Module Dhcp Level PCR Module Ospf LevelPCR 40487 Module Core Level PCR 40516 Module Dhcp Level PCR Module Vrrp LevelPCR 40520 Module Dvmrp Level PCR Module Classifier LevelPCR 40544 Module Vlan Level PCR 40543 Module Swmx LevelPCR 40550 Module Swmx Level PCR Module QoS LevelPCR 40571 Module Swmx Level PCR 40592 Module Bootp LevelPCR 40574 Module Swmx Level PCR 40586 Module Swmx LevelPCR 40521 Module TACACS+ PCR 40525 Module SWI, SWX LevelPCR Module Rstp PCR Module PIM4 Level PCR Module NTP LevelPCR Module Ipsec Level PCR Module PIM LevelPCR Module IPv6 Level PCR Module PPP LevelPCR 40405 Module Enco Level PCR Module SWMX,SWI LevelPCR 40416 Module QOS Level PCR 40413 Module QOS LevelPCR 40418 Module Swmx Level PCR Module Firewall LevelPCR 40433 Module VLANLevel PCR 40431 Module SWMXLevelPCR 40440 Module CLASSIFIERLevel PCR 40441 Module IPG, VRRPLevelPCR 40409 Module Swnp Level PCR 40509 Module Swmx LevelPCR 40371 Module Vlan Level PCR 40351 Module Vlan Level PCR 40313 Module Swnp LevelPCR 40352 Module Swnp Level PCR 40363 Module Swnp LevelPCR 40367 Module Swmx Level PCR 40365 Module EZDRV, IPv6, Swnp LevelPCR 40376 Module QOS Level PCR 40396 Module Swmx LevelPCR Module IPG, SWI Level PCR 40382 Module Swmx LevelPCR Module IGMP, SWI Level PCR Module IPGPCR Module PIM6 PCR 40249 Module SWI, SwmxPCR 40274 Module VLAN, Rmon Level PCR Module IPG, IPV6 LevelPCR 40334 Module Vlan Level PCR Module TM LevelPCR 40338 Module Vlan Level PCR 40341 Module SWMX, SWIPCR 40213 Module QOS PCR 40196 Module SWNP, EzdrvPCR 40224 Module Ezdrv PCR 40245 Module SwnpPCR Module IPV6 PCR Module OspfShow ip igmp Igmp Snooping All-Group EntryEnable ip igmp allgroup Enable ip igmp allgroupIgmp Snooping Disable ip igmp allgroupDescription where Add igmpsnooping routeraddressDelete igmpsnooping routeraddress Set igmpsnooping routermodeIcmp Redirect Messages for IPv6 Show igmpsnooping routeraddressImport Importing BGP routes into OspfParameter Option/Range Description Set ospfShow ospf Example output from the show ospf commandAvailability Add ip filter
Top Page Image Contents