Limited EIGRP Traffic redistribution

[TRACY HARTMANN]

I currently have a MPLS network connected to a layer 3 switch and then a point to point also connected to that layer 3 switch.  I would like to use the point to point since it is faster and have the MPLS for backup.   This site is not a hub site, there is nothing in back of it.   I am running EIGRP and have the network defined.   I can run the MPLS or the point to point.  However if both are running at the same time the MPLS basically takes over and tries to get the ENTIRE network to route through the MPLS.  I am thinking their is a problem with a routing loop.  Since the routes are learned from the point to point.   What is the best way to not have "learned" routes be re-adversited back into the mpls?   Maybe some kind of distribution list ?

ATT Router ------layer 3 switch------point - to -point ----- layer 3 switch

Thanks

[Georg Pauwen]

Hello,

you can use a distribute list (with a route map) to control inbound or outbound filtering.

I am not really clear on your topology: does your EIGRP have to exit points, and you want to prefer one over the other ? If so, you would typically change the cost of the EIGRP interface (a higher cost would make the interface less preferable). Maybe you can post the configuration of the device where the filtering should occur, and indicate which routes you want to go where...

[TRACY HARTMANN]

Yes I have two EIGRP connections.  I do have a better metric on one and that all works fine.   The issue is that when they are both active the routes that are behind the point to point get through our switch out the the MPLS and creates a loop.  So I am trying to get those routes from being advertised to the MPLS router.

[Georg Pauwen]

Hello,

here is an example. Let's say wou want to keep 192.168.1.0/24 and 192.168.2.0/24 from being advertised to the MPLS, you would configure the below (assuming GigabitEthernet0/0 is the interface connected to the MPLS side):

access-list 10 deny 192.168.1.0 0.0.0.255
access-list 10 deny 192.168.2.0 0.0.0.255
access-list 10 permit any
!
router eigrp 1
distribute-list 10 out GigabitEthernet0/0

[paul driver]

Hello

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@Georg Pauwen wrote:

Hello,

here is an example. Let's say wou want to keep 192.168.1.0/24 and 192.168.2.0/24 from being advertised to the MPLS, you would configure the below (assuming GigabitEthernet0/0 is the interface connected to the MPLS side):

access-list 10 deny 192.168.1.0 0.0.0.255
access-list 10 deny 192.168.2.0 0.0.0.255
access-list 10 permit any
!
router eigrp 1
distribute-list 10 out GigabitEthernet0/0

---

The problem with the above is if the preferred link went down then you wouldn’t have the resiliency!

[TRACY HARTMANN]

I think the access-list with the distribution list would work.  But when you say if the Primary circuit goes down it won't go out the backup why?  The only routes I don't want advertised are ones learned from the Primary route the connected routes are the only ones I want to advertise.

For Example

Primary point EIGRP  10.30.0.0------switch EIGRP local lans 10.4.0.0 ----MPLS

I don't want the 10.30.0.0 advertised to MPLS so would the following work

access-list 10 permit 10.30.0.0 0.0.0.255
access-list 10 permit any 
!
router eigrp 1
distribute-list 10 out GigabitEthernet0/0

The reason I would like to do the permit instead of deny is I have a lot more routes being learned from the point to point so it would be easier to permit the connected subnets .

Thanks

[Georg Pauwen]

Hello,

I guess that should work. Since you don't want those routes to go out through the MPLS link, that link is not really a secondary route, hence you don't have to worry about cutting off the 'backup'...

[paul driver]

Hello Tracy

---

@TRACY HARTMANN wrote:

I currently have a MPLS network connected to a layer 3 switch and then a point to point also connected to that layer 3

ATT Router ------layer 3 switch------point - to -point ----- layer 3 switch

---

You dont provide enough information here, If your routing leaking then it doesnt show in this eigrp topology, TBH I dont really understand the above setup.
You have a P2P connection betweeen the two L3 switchs, one is eigrp peering with ATT and the other is peered with what aprtf rom the other L3 switch?
Are are you redistrubting in eigrp ,Are you using the same eigrp routing domain.

The most simplistic way would be to increase the admin distance to the least preffered path advertisng router like below for internal eigrp routes however without a more detail explanation on your network it would be hard to provide a positive suggestion.

router eigrp xx
distance 91 <advertising rtr> 0