BGP Local Subnets Redistribution into IGP

[amr mubarak]

Dears,

when  I am redistributing localy originated BGP prefix by local router into IGP ,i have notcied the below in the following case

1.When IGP is OSPF for IPV4-->The local BGP routes on redistributing router aren't redistributed into OSPF

This can be done only by using redistribute command under ospf

2.When IGP is EIGRP for IPV4-->The local BGP routes on redistributing router can be redistributed into EIGRP

3.When IGP is either EIGRP or OSPF for IPV6-->

The local BGP routes on redistributing routers aren't redistributed into OSPF/EIGRP

This can be done only by using redistribute command under ospf/EIGRP

Please if someone can provide me the reason for that is this is special only for local bgp routes into IGP

Thanks

For illustration :R1-->IGP-->R2-->E-BGP-->R3  ||||||||  on R2 the loopback is advertised by BGP through network command and according to above case R2_Loopback can be or not advertised into IGP depending on the case

[Jon Marshall]

Your post is not clear.

What do you mean by local BGP routes ?  

If you want to redsitribute BGP into an IGP you need to use the redistribute command although case 2) above suggests differently.

Can you perhaps give a more detailed explanation as to what you mean ?

Jon

[amr mubarak]

Hi Jon,

To provide more clarification ,please check below

According to the simple topology " R1--->IGP-->R2-->E-BGP-->R3 "

1.IGP is running between R1&R2 while EBGP is running between R2&R3

2.On R2 ,R2_Loopback is advertised into bgp through network command

while no IGP is running under R2_Loopback

2.The bgp routes are redistributed into IGP

router

redistribute bgp

A.When IGP is EIGRP for IPV4-->R2_Loopback is advertised into EIGRP when BGP is redistributed into EIGRP which is normal

B.When IGP is OSPF for IPV4-->R2_Loopback isn't advertised into OSPF when BGP is redistributed into OSPF.To advertise R2_Loopback into OSPF,either redistribute connected under OSPF or run OSPF under R2_loopback

3.When IGP is either EIGRP or OSPF for IPV6-->

R2_Loopback isn't advertised into either OSPF/EIGRP when BGP is redistributed into OSPF/EIGRP

This can be done only by using redistribute command under ospf/EIGRP

Appreciate your feedback

[Julio Carvajal]

Hello amr.

If you do a show ip bgp

Do you see the loopback address on the BGP NLRI table?

On OSPF you need the following

router ospf #

redistribute bgp # subnets

Is that what you are doing?

Looking for some Networking Assistance? 
Contact me directly at jcarvaja@laguiadelnetworking.com

I will fix your problem ASAP.

Cheers,

Julio Carvajal Segura
http://laguiadelnetworking.com

[amr mubarak]

Hello Julio,

Yes ,the R2_lo is in BGP table and redistribute subnets already implemented.I think it is related to IOS 12.2(33).

FOr IPV6 i did further searching and found that connected networks which are advertised by IGP aren't advertised by default so in case of redistribution of IGP into BGP ,the keywork "redistribute (IGP) included-connected" is needed under bgp so i think it will be the same case when redistributing from BGP to IGP and since this keywork isn't exist when redistibuted routing protocol is BGP so i think redistribute connected is needed under IGP.

The pending thing now for IPV4 when routing protocol is OSPF may be it is IOS related issue so thanks for verifiying

[Julio Carvajal]

Hello Amr,

The configuration looks good,

It does not make any sense so we could be dealing with something buggy here.

Can you do something first:

do a

show ip ospf database external adv-router (your router-id) and see what you advertise. You should see the BGP route.

Looking for some Networking Assistance? 
Contact me directly at jcarvaja@laguiadelnetworking.com

I will fix your problem ASAP.

Cheers,

Julio Carvajal Segura
http://laguiadelnetworking.com