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Redistribution question

I?m trying to redistribute BGP into EIGRP and am having some problems. I?m not seeing any of the BGP routes in EIGRP.

I have attached the configurations of each router I?m working with. The one labeled ?tazwellopps2851? is the head end router. These two routers are connected via MPLS.

The tazwellopps2851 router is connected to another Cisco router that is terminating several P2P T-1?s. I had to configure a static router pointing to 192.168.4.0 on this router in order to get connectivity to this network.

Any help you could give me would be very much appreciated!!

24 REPLIES
Hall of Fame Super Gold

Re: Redistribution question

Chris

I have looked at the configs that you posted. The biggest problem that I see is that when you redistribute BGP into EIGRP there is no default metric specified. When EIGRP attempts to learn the routes from BGP it has no metric to apply to them (and cetainly the way that BGP decides on routes does not translate into a metric that EIGRP could use). So EIGRP can not learn the BGP routes. I suggest that you configure a default-metric statement under router EIGRP (or you could easily add the metric paramters on the redistribute statement).

default-metric 100000 100 255 1 1500

or

redistribute bgp 65123 metric 100000 100 255 1 1500

Give that a try and let us know what happens.

HTH

Rick

New Member

Re: Redistribution question

Rick,

First thanks for the post.

Can you give me an example of the metric I could use under the default-metric statement?

Thanks very much!!

Chris

Hall of Fame Super Gold

Re: Redistribution question

Chris

default-metric 100000 100 255 1 1500

or

redistribute bgp 65123 metric 100000 100 255 1 1500

Give that a try and let us know what happens.

HTH

Rick

New Member

Re: Redistribution question

I just added redistribute bgp 65123 metric 100000 100 255 1 1500 to my EIGRP configuration on the tazwellopps2851. Didn't seem to change anything. EIGRP seems to be redistributing its routes into BGP because I can see all route on the maynardville router. BGP isn't redistributing its routes..

Hall of Fame Super Bronze

Re: Redistribution question

Please post the output from

show ip bgp

show ip eigrp topology

New Member

Re: Redistribution question

Here's the requested information from the tazwellopps router.

Hall of Fame Super Bronze

Re: Redistribution question

Chris,

I browsed your file real quick and found most networks listed in BGP are redistributed into EIGRP topology, for instance:

P 12.112.64.160/30, 1 successors, FD is 51200, tag is 7018

via Redistributed (51200/0)

How are you verifying redistribution ?

Via show ip route ?

Remember, if both routing protocols are advertising the same route to the same destination, eBGP will be preferred due to its administrative distance.

New Member

Re: Redistribution question

I remove the static route and I no longer have connectivity.

Once I remove this static route, I never see a route for this network.

I have included in the attachment the output from show ip eigrp top command for one of the networks I am having problems with. It looks to me like this network is being redistributed from BGP.

Hall of Fame Super Bronze

Re: Redistribution question

It's learned from BGP indeed !

However, you mentioned that removing the static route breaks the connection which makes me think the network also disappear from the BGP table as well ?

If BGP doesn't have this network on its table, it won't be able to redistribute into EIGRP.

Hall of Fame Super Gold

Re: Redistribution question

Chris

There are some things that I am puzzled about. Is router fcb_tazewell the router with address 192.168.1.3?

I see in that table that you posted from tazwellopps2851 that it had learned 10.200.4.0 from 192.168.1.3 with advertised metric of 28160. On fcb_taxwell it seems to have learned that route from redistribution of static with metric 28160 and also learned it from 192.168.1.250 which is tazwellopps2851 via redistribution of BGP.

I am also puzzled about the number of routers that you have that are in AS65123 for BGP. But the configs that you have posted they only have external neighbors in other ASes. Can you clarify the topology and the relation between the various routers?

HTH

Rick

New Member

Re: Redistribution question

Rick,

fcb_tazewell is 192.168.1.3.

192.168.3.1 has a static route for 10.10.4.0, 10.200.4.0, and 192.168.4.0 that points to tazwellopps2851.

If redistribution is working correctly, 192.168.1.3 should learn routes to 10.10.4.0, 10.200.4.0, and 192.168.4.0 from tazwellopps2851 because these networks are connected to another router off of tazwellopps2851.

Networks 10.10.4.0, 10.200.4.0, and 192.168.4.0 are connected to tazwellopps2851 via an MPLS link.

Let me know if you have any other questions.

Thanks,

Chris

Hall of Fame Super Bronze

Re: Redistribution question

Now I see why you need a static route in order for the route to network 10.200.4.0 255.255.255.0 be installed into BGP. On the router fcb_tazewell, you have

router bgp 65123

synchronization

You need to disable synchronization in order for iBGP routes to be installed into the BGP table.

Please rate helpful posts.

Thanks

New Member

Re: Redistribution question

Okay, I have removed disabled the synchronization command under router bgp 65123.

How can I tell if this is going to work without removing the static routes?

What does the synchronization command do anyway?

Thanks again!!!!

Hall of Fame Super Bronze

Re: Redistribution question

So you typed

'no synchronization'

Good !

When you have synchronization on, a route learned from another iBGP (a BGP peer running in the same AS) will not be installed in the BGP Routing table. The route can only be installed by using IGP, in your case a static route.

You can tell if it's going to work by issuing

show ip bgp

on that router.

The path should listed 'i' as the origin code.

New Member

Re: Redistribution question

I entered the no synchronization command. But when I do a sh ip bgp it looks the same as when I had synchronization enabled. I have attached the output from this command before and after I entered the no syn command.

What is up with this??

Thanks for explaining to me what the synchronization command is!

New Member

Re: Redistribution question

Sorry, here's the attachments.

Hall of Fame Super Bronze

Re: Redistribution question

Chris,

The BGP table is posted from the working router. I need the BGP table from fcb_tazewell which is the router with the problem.

New Member

Re: Redistribution question

This router doesn't run BGP. This router is on the same ethernet network as the tazwellopps router, which is the one doing the BGP to EIGRP redistribution. Tazwellopps router connects via MPLS to the maynardville router, which is sourcing the networks of 10.10.4.0, 10.200.4.0 and 192.168.4.0 via BGP.

Does this help?

Thanks for all of your help with this!!

Hall of Fame Super Bronze

Re: Redistribution question

Chris, see my other reply on your problem. You need to configure iBGP between tazwellopps2851 and Maynardville2811

Hall of Fame Super Bronze

Re: Redistribution question

Can I see the 'show ip bgp' from both routers ?

Hall of Fame Super Gold

Re: Redistribution question

Edison

I am not sure that synchronization is the issue. As far as I can tell from the configs that I see posted the router that had synch enabled has only one neighbor configured and that is an external neighbor. Synch becomes a factor when there are iBGP routes. An eBGP route should be installed anyway. Do you see something different from what I see?

If 10.200.4.0 is one of the networks that is a problem I wonder if Chris can clarify:

- where is this network located?

- which router is supposed to have the original advertisement? Is it a onnected interface or a static route?

- which protocol makes the original advertisement?

- from the router that originates the route, to which router and by which protocol is the route advertised?

If we can understand the topology better I think we might more quickly find the explanation.

HTH

Rick

New Member

Re: Redistribution question

1) 10.10.4.0, 10.200.4.0 and 192.168.4.0 are all on maynardville router.

2) The maynardville should be sending these routes via BGP to tazwellopps2851 which should be redistributing them into EIGRP. 192.168.1.3 should see these EIGRP routes. BGP doesn't run on 192.168.1.3.

3)BGP will make the original advertisement.

Let me know if this helps.

Hall of Fame Super Bronze

Re: Redistribution question

Rick,

I mentioned sync becomes a factor when trying to advertise routes via iBGP, never mentioned eBGP.

However, I failed to notice that both routers are pointing to an eBGP neighbor and never to each other.

From the configs that Chris has posted:

10.200.4.0 is under Maynardville2811

interface Loopback0

ip address 10.200.4.250 255.255.255.0

which is only running the BGP protocol

tazwellopps2851 is running both EIGRP and BGP and he wants the BGP table eBGP and iBGP into EIGRP.

However, now that I have time to look closely, I see the problem. He doesn't have a neighbor statement pointing to Maynardville2811 from tazwellopps2851 and viceversa.

So the question goes back to Chris. In order to have a iBGP peer between these 2 devices, you need to include their respective IP addresses as neighbor under the BGP process. The IP address used must be reachable from one end to the other.

Re: Redistribution question

Chris,

Do you see a EIGRP neighbor with 192.168.1.3 on the tazwellopps2851 router?

If you do see a neighbor then can you do a 'show ip eigrp top 10.200.4.0 255.255.255.0' on the router configured with the address of 192.168.1.3

-Sundar

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