BGP Redistribution question
While looking into a routing issue, I found that one of my routers wasn't passing one of my static routes, being redist into ospf into bgp, and not sure as to why. It has been a while since I have worked with BGP, so I am a little rusty. The solution was for me to add the following BGP network statement... network 10.86.8.0 mask 255.255.248.0. If statics are being redist info ospf, and ospf is basically being redist into bgp, why did I have to have the network statement. Why didn't it put it into BGP and pass it along? Here is the scenario: Router A: ip route 10.86.8.0 255.255.248.0 10.86.138.14 ATL--CR6513A#ping 10.86.138.14 success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms ATL -CR6513A#sh ip route 10.86.8.0 Routing entry for 10.86.8.0/21 Known via "static", distance 1, metric 0 Redistributing via ospf 1 Advertised by ospf 1 subnets bgp 2 Routing Descriptor Blocks: * 10.86.138.14 Route metric is 0, traffic share count is 1 ATL-CR6513A#sh ip ospf data ext 10.86.8.0 OSPF Router with ID (10.86.194.5) (Process ID 1) Type-5 AS External Link States Routing Bit Set on this LSA LS age: 898 Options: (No TOS-capability, DC) LS Type: AS External Link Link State ID: 10.86.8.0 (External Network Number ) Advertising Router: 10.86.194.2 LS Seq Number: 80000D87 Checksum: 0x3D49 Length: 36 Network Mask: /21 Metric Type: 2 (Larger than any link state path) TOS: 0 Metric: 20 Forward Address: 0.0.0.0 External Route Tag: 0 LS age: 554 Options: (No TOS-capability, DC) LS Type: AS External Link Link State ID: 10.86.8.0 (External Network Number ) Advertising Router: 10.86.194.5 LS Seq Number: 80000D87 Checksum: 0x2B58 Length: 36 Network Mask: /21 Metric Type: 2 (Larger than any link state path) TOS: 0 Metric: 20 Forward Address: 0.0.0.0 External Route Tag: 0 ATL-CR6513A#sh ip bgp 10.86.8.0 BGP routing table entry for 10.86.0.0/16, version 1078065 Paths: (2 available, best #2, table Default-IP-Routing-Table) Multipath: eBGP Advertised to non peer-group peers: 10.1.2.9 1, (aggregated by 1 10.1.254.253) 10.1.2.9 from 10.1.2.9 (10.1.254.253) Origin IGP, metric 0, localpref 100, valid, external, atomic-aggregate, multipath 1, (aggregated by 1 10.1.254.252) 10.1.2.1 from 10.1.2.1 (10.1.254.252) Origin IGP, metric 0, localpref 100, valid, external, atomic-aggregate, multipath, best router ospf 1 redistribute static subnets router bgp 2 no synchronization network x.x.x.x network y.y.y.y network 10.86.8.0 mask 255.255.248.0 ***had to be added for this to work, but wasn't present before hand*** redistribute connected route-map OSPF-Links redistribute ospf 1 route-map WW-OSPF-Routes neighbor 10.1.2.1 remote-as 1 neighbor 10.1.2.1 advertisement-interval 1 neighbor 10.1.2.9 remote-as 1 neighbor 10.1.2.9 advertisement-interval 1 maximum-paths 2 no auto-summary route-map WW-OSPF-Routes permit 10 set metric-type internal This is I was seeing on my Upstream Core router: ATL -CR12406A#sh ip route 10.86.8.0 Routing entry for 10.86.0.0/16 Known via "bgp 1", distance 200, metric 0, type locally generated Routing Descriptor Blocks: * directly connected, via Null0 Route metric is 0, traffic share count is 1 AS Hops 0, BGP network version This is what I was seeing after I add the network statement: GAATL-WW1-CR12406A#sh ip bgp 10.86.8.0 BGP routing table entry for 10.86.8.0/21, version 2210556 Paths: (2 available, best #2, Advertisements suppressed by an aggregate.) Multipath: eBGP iBGP Not advertised to any peer 2 10.1.2.2 from 10.1.2.2 (10.86.194.5) Origin IGP, metric 0, localpref 100, valid, external, multipath 2 10.1.2.6 from 10.1.2.6 (10.86.194.2) Origin IGP, metric 0, localpref 100, valid, external, multipath, best __________________________________ Do you Yahoo!? Yahoo! Mail Address AutoComplete - You start. We finish. http://promotions.yahoo.com/new_mail
Hello. Redistribute ospf xx subnets has some unusual behavior compared to other redistribution mechanisms. Instead of dumping everything from ospf into the other routing protocol, it only does a subset of routes. (If I remember right, only "internal" routes.) I think the command you probably want is... Redistribute ospf 123 match internal external 1 external 2 Also, if you have nssa's, you may have to tack nssa-external on the end of that. Good luck, Ejay P.s. Unidrectional redistribution good. Bidirectional redistribution Bad
-----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of D Train Sent: Thursday, August 05, 2004 10:09 AM To: nanog@nanog.org Subject: BGP Redistribution question
While looking into a routing issue, I found that one of my routers wasn't passing one of my static routes, being redist into ospf into bgp, and not sure as to why. It has been a while since I have worked with BGP, so I am a little rusty. The solution was for me to add the following BGP network statement... network 10.86.8.0 mask 255.255.248.0. If statics are being redist info ospf, and ospf is basically being redist into bgp, why did I have to have the network statement. Why didn't it put it into BGP and pass it along?
Here is the scenario: Router A: ip route 10.86.8.0 255.255.248.0 10.86.138.14
ATL--CR6513A#ping 10.86.138.14 success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms
ATL -CR6513A#sh ip route 10.86.8.0 Routing entry for 10.86.8.0/21 Known via "static", distance 1, metric 0 Redistributing via ospf 1 Advertised by ospf 1 subnets bgp 2 Routing Descriptor Blocks: * 10.86.138.14 Route metric is 0, traffic share count is 1
ATL-CR6513A#sh ip ospf data ext 10.86.8.0 OSPF Router with ID (10.86.194.5) (Process ID 1) Type-5 AS External Link States Routing Bit Set on this LSA LS age: 898 Options: (No TOS-capability, DC) LS Type: AS External Link Link State ID: 10.86.8.0 (External Network Number ) Advertising Router: 10.86.194.2 LS Seq Number: 80000D87 Checksum: 0x3D49 Length: 36 Network Mask: /21 Metric Type: 2 (Larger than any link state path) TOS: 0 Metric: 20 Forward Address: 0.0.0.0 External Route Tag: 0 LS age: 554 Options: (No TOS-capability, DC) LS Type: AS External Link Link State ID: 10.86.8.0 (External Network Number ) Advertising Router: 10.86.194.5 LS Seq Number: 80000D87 Checksum: 0x2B58 Length: 36 Network Mask: /21 Metric Type: 2 (Larger than any link state path) TOS: 0 Metric: 20 Forward Address: 0.0.0.0 External Route Tag: 0
ATL-CR6513A#sh ip bgp 10.86.8.0 BGP routing table entry for 10.86.0.0/16, version 1078065 Paths: (2 available, best #2, table Default-IP-Routing-Table) Multipath: eBGP Advertised to non peer-group peers: 10.1.2.9 1, (aggregated by 1 10.1.254.253) 10.1.2.9 from 10.1.2.9 (10.1.254.253) Origin IGP, metric 0, localpref 100, valid, external, atomic-aggregate, multipath 1, (aggregated by 1 10.1.254.252) 10.1.2.1 from 10.1.2.1 (10.1.254.252) Origin IGP, metric 0, localpref 100, valid, external, atomic-aggregate, multipath, best
router ospf 1 redistribute static subnets router bgp 2 no synchronization network x.x.x.x network y.y.y.y network 10.86.8.0 mask 255.255.248.0 ***had to be added for this to work, but wasn't present before hand*** redistribute connected route-map OSPF-Links redistribute ospf 1 route-map WW-OSPF-Routes neighbor 10.1.2.1 remote-as 1 neighbor 10.1.2.1 advertisement-interval 1 neighbor 10.1.2.9 remote-as 1 neighbor 10.1.2.9 advertisement-interval 1 maximum-paths 2 no auto-summary
route-map WW-OSPF-Routes permit 10 set metric-type internal
This is I was seeing on my Upstream Core router: ATL -CR12406A#sh ip route 10.86.8.0 Routing entry for 10.86.0.0/16 Known via "bgp 1", distance 200, metric 0, type locally generated Routing Descriptor Blocks: * directly connected, via Null0 Route metric is 0, traffic share count is 1 AS Hops 0, BGP network version
This is what I was seeing after I add the network statement:
GAATL-WW1-CR12406A#sh ip bgp 10.86.8.0
BGP routing table entry for 10.86.8.0/21, version 2210556
Paths: (2 available, best #2, Advertisements suppressed by an aggregate.)
Multipath: eBGP iBGP Not advertised to any peer 2 10.1.2.2 from 10.1.2.2 (10.86.194.5) Origin IGP, metric 0, localpref 100, valid, external, multipath 2 10.1.2.6 from 10.1.2.6 (10.86.194.2) Origin IGP, metric 0, localpref 100, valid, external, multipath, best
__________________________________ Do you Yahoo!? Yahoo! Mail Address AutoComplete - You start. We finish. http://promotions.yahoo.com/new_mail
participants (2)
-
D Train -
Ejay Hire