IBGP redistribution into OSFP on NXOS

[jbulloch]

Hi community,

So i want to get some IBGP routes between two NXOS nodes, where one is running IGBP into the IGP (OSPF) onto the other node. This is to support a VM setup that the sever team claims has to come up on BGP and then be converted to our standard OSPF afterwards.

I have created a BGP neighbour ship between the two (7878) and i see the routes on the IGP device. There are 6 SVI's and this seems to be working as intended:

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
172.20.x.x 4 7878 160 158 41 0 0 02:09:59 6

Show IP BGP for the default VRF can see the subnets:

est2

Network Next Hop Metric LocPrf Weight Path
*>i172.21.49.0/24 172.20.0.38 100 0 i
*>i172.21.50.0/24 172.20.0.38 100 0 i
*>i172.21.53.0/24 172.20.0.38 100 0 i
*>i172.21.72.0/27 172.20.0.38 100 0 i
*>i172.21.73.0/25 172.20.0.38 100 0 i
*>i172.21.74.0/28 172.20.0.38 100 0 i

So i have configed:

ip prefix-list VMINTOA2 seq 1 permit 172.21.49.0/24
ip prefix-list VMINTOA2 seq 2 permit 172.21.50.0/24
ip prefix-list VMINTOA2 seq 3 permit 172.21.53.0/24
ip prefix-list VMINTOA2 seq 4 permit 172.21.72.0/27
ip prefix-list VMINTOA2 seq 5 permit 172.21.73.0/25
ip prefix-list VMINTOA2 seq 6 permit 172.21.74.0/28
route-map VM2INTOA2 permit 10
match ip address prefix-list VMINTOA2
match route-type internal

And:

router ospf 1
redistribute bgp 7878 route-map VM2INTOA2

But i am not getting the routes into OSPF table. I've read of the need to place a 'redist internal' command under the bgp router, but this does not seem to be an option on NXOS? Am i missing a configuration step here?

Thank you for your assistance.

[MHM Cisco World]

https://www.cisco.com/c/en/us/support/docs/switches/nexus-9000-series-switches/220615-configure-route-redistribution-on-nexus.html#toc-hId-534960356

Did you use route-map?

MHM

[MHM Cisco World]

Check this also

https://www.cisco.com/c/en/us/support/docs/ios-nx-os-software/nx-os-software/200185-Configure-Redistribution-of-iBGP-Routes.html

MHM

[jbulloch]

MHM, yes

Route map is simple:

route-map VM2INTOA2 permit 10
match ip address prefix-list VMINTOA2
match route-type internal

called under OSPF instance:

redistribute bgp 7878 route-map VM2INTOA2

I have a similar, cheating allow all for OSPF traffic back to BGP (0.0.0.0/0).

[MHM Cisco World]

VMINTOA2 <<- can I see this prefix list 

MHM

[jbulloch]

Sure, posted above

ip prefix-list VMINTOA2 seq 1 permit 172.21.49.0/24
ip prefix-list VMINTOA2 seq 2 permit 172.21.50.0/24
ip prefix-list VMINTOA2 seq 3 permit 172.21.53.0/24
ip prefix-list VMINTOA2 seq 4 permit 172.21.72.0/27
ip prefix-list VMINTOA2 seq 5 permit 172.21.73.0/25
ip prefix-list VMINTOA2 seq 6 permit 172.21.74.0/28

[MHM Cisco World]

show ip ospf database external <<- can you share this please 

MHM

[jbulloch]

Sure,

[MHM Cisco World]

I see all prefix in ospf DB' so redistrubte is OK.

There something else 

External peer- ibgp - NSK1 - ospf - NSK2 

You do redistrubt between ibgp and ospf in NSK1 and it OK (from show database ospf)

NSK2 dont receive this prefix??

This issue in ospf then' 

Did you check ospf neighbor' see if each NSK see each other 

MHM

[jbulloch]

MHM,

What is 'NSK'? You're using it in reference to a switch, but i know this as network security key. 

[MHM Cisco World]

Nexus >> NSK

MHM

[jbulloch]

Hi MHM, downstream ospf neighbors also have the external routes in the database.

[MHM Cisco World]

In DB only or in DB and RIB ?

In NSK1 it normal to see prefix in RIB (with B letter i.e. it learn via bgp)

In NSK2 you should see it in RIB ( O E1/2)

MHM

[jbulloch]

Yes, nx-os seems to show ip route a bit different, but it's there:

(show ip route)

172.21.49.0/24, ubest/mbest: 1/0 time
*via 172.20.0.38, [200/0], 1d02h, bgp-7878, internal, tag 7878
172.21.50.0/24, ubest/mbest: 1/0 time
*via 172.20.0.38, [200/0], 1d02h, bgp-7878, internal, tag 7878

and on down steam for instance (this is a ios xe device)

O E2 172.21.72.0/27
[110/1] via 157.141.201.21, 1d01h, TenGigabitEthernet2/1/2
[110/1] via 157.141.201.17, 1d01h, TenGigabitEthernet1/1/6
O E2 172.21.73.0/25
[110/1] via 157.141.201.21, 1d01h, TenGigabitEthernet2/1/2
[110/1] via 157.141.201.17, 1d01h, TenGigabitEthernet1/1/6

[MHM Cisco World]

There is no issue then if yoh see prefix in ios xe router.

MHM