route-map configuration assistance

Answered Question
Oct 19th, 2009

Does anyone have a link to something that will explaine route-map configuration? I have been searching CCO and so far have not found anything really helpful.

What I am trying to do is configure my internet router so that based upon the status of the link to my ISPs, a default route will be passed back into the core. I have added a secondary ISP and need the default route to change depending on the status of the primary link. I was thinking of setting the default route to the primary with a low metric and the default route to the secondary with a higher route by default. If the ping failed the primary default route would be reset with an even higher route, or removed completely, thus rolling traffic to the secondary. When the primary returned the primary default would be reset to its lower value and normal traffic flow would resume.

I have an IP SLA configured to monitor the primary link via a ping but I am having a hard time figuring out the route-map to set the default. I have an ACL with the ISP address to match and am thinking to use EIGRP to get the default back into the core and eleminate the manual static.

Basically I have:

MPLS|corporate core|PIX|internet|ISP1

MPLS|remote core|PIX|internet|ISP2

I can manually make changes and make the roll of traffic happen but figurer there is a better automated way. In looking through confog guids and case studies on CCO, I think I have the pieces, just having problems putting them all together.


I have this problem too.
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Correct Answer by simontibbitts about 7 years 3 months ago

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simontibbitts Mon, 10/19/2009 - 07:33

Hi Brent.

How are you creating the default route on your router? Is it being advertised by the ISPs or are you generating it yourself?

The answer to this question will make the difference as to which is the best solution to you.

Have you seen the feature with the static routes which allow an IP SLA be tracked? What the configuration below does is add a route depending on the IP SLA. (You can have another default route with a higher AD to your other ISP to take over)


ip sla monitor 200

type echo protocol ipIcmpEcho x.x.x.x

timeout 500

frequency 3

ip sla monitor schedule 200 life forever start-time now


track 13 rtr 200 reachability


ip route x.x.x.x track 13



bberry Mon, 10/19/2009 - 07:48

I though I would set it manually and use the redistribute static in EIGRP to get it to the inside. I would also set a default manually on the secondary link with say the admin distance of 180 (170 is default right). This too would be redistributed toward the core from the secondary location. When the primary then failed I was thinking of either removing the primary default or push its admin distance to say 200. The reason that I am thinking using the default routes is that in our case I have the ISPs in two geographic locations.

This ip sla is what I have for using the ping to track the up/down of the primary link, minus the ip route. I just do not know how to get from there to the touting table modification.

With this ip route and the track 13, this route would drop out if the ip sla monitor failed?


simontibbitts Mon, 10/19/2009 - 07:56

Hi Brent.

In that case the configuration I have showed you is perfect for your setup. All you need to do is tie your IP SLA to a 'track' number and then add the track number to your primary default route, you'll end up with two static routes like this:

ip route x.x.x.x track 13

ip route y.y.y.y 50

(Where x.x.x.x is your primary next hop IP and y.y.y.y is your secondary next hop IP)

EIGRP will just advertise the default route regardless of which one is being used. Only this router you are configuring needs to know which link is in use.


bberry Mon, 10/19/2009 - 08:12

That will be cool .. getting easier than I thought.

One more question. I currently have an occurance of EIGRP and BGP running in my core. EIGRP because I use that on the LAN for my VLAN distribution and BGP because that is what I use with my MPLS provider. Not a problem to add in the instance running to the internet?

Gonna make me get my other routing references out now.


simontibbitts Mon, 10/19/2009 - 08:29

Hi Brent.

I am not sure I fully understand your new question. Your new configuration we have discussed will not be affected even if BGP is running over those links to the ISPs.

However if you are running BGP with those two ISPs and are receiving routes from them then you can always use BGP to initiate the failover from one ISP to another.

If you mean will it affect some other MPLS links you have elsewhere in your network - then no - it's won't

Static routes are only local to the router to configure them on. EIGRP will just advertise the default regardless of which ISP it is pointing out.


bberry Mon, 10/19/2009 - 08:35

I think I am slowly getting it ..

I run BGP internally with my corporate MPLS network. On those locations that are large enough I also run EIGRP for supporting the VLANS and I redistribute that instance on EIGRP into BGP. This is so that the rest of the corporation learns those networks.

Since I now have an instance of EIGRP running on my internet router, will pass it through my pix, and into the core for redistribution, Should it be the same EIGRP I am running in the core to support my VLANS or should it be a different instance? I am thinking different so that my corporate networks cannot bleed out to the interent.

Yeah .. I am showing the default in the ip route track-table but should I also see it in the EIGRP table?

Mem_Int_Outside#sh ip route track-table

ip route track 101 state is [up]


Mem_Int_Outside#sh ip route eigrp 20



simontibbitts Mon, 10/19/2009 - 08:46

Hello Brent.

From what you have said I think it should be the SAME EIGRP instance. You don't have to worry about 'bleeding' routes into the internet as you don't have a EIGRP neighbor with the internet routers, you are just static routing so you are not feeding them any routes at all.

You will not see a default route with EIGRP marked against it on Mem_Int_Outside as this router will be using the static route as it has a better AD. You might see it in 'show ip eigrp topology'

If you have redistributed it correctly then you WILL see EIGRP with a default route on your other EIGRP routers.


bberry Mon, 10/19/2009 - 08:51

cool .. thanks for the assistance .. Now I have to go see if PIX IOS 8.0 really supports EIGRP. *S*

I will be SO glad when I can move to an ASA. This will become much easier.



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