OSPF

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Jun 2nd, 2007
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Hi,


we have two WAN link from location A to location B. we would like to split the traffic two WAN link (no load balancing). it is


192.168.10.0 --> WAN 1 --> 172.16.1.0

192.168.20.0 --> WAN 2 --> 172.16.1.0


how do I influent the routes to right paths? please advice


best regards

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balajitvk Sat, 06/02/2007 - 21:57
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Hi,


Here you want to split the outgoing traffic based on the source subnet. I don't think OSPF will do for you.....


If it is incoming traffic, you can do the destination based loadbalncing on the other end router... but for the Outgoing traffic based on source subnet, i suppose you need to go for PBR on bgp....


Rgs,

ruwhite Sun, 06/03/2007 - 04:03
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I'm not certain I understand the question, but.... If you are trying to get it so all traffic destined to 192.168.10.0 goes along wan 1, and all traffic destined to 192.168.20.0 goes along wan 2, and you don't want any sort of backup, and both wan 1 and wan 2 wind up at two different routers, then.... (a lot of if's)....


You can apply a distribute list in on the router attached to wan 1 so it won't install the route to 192.168.20.0 in it's local RIB, and you can apply a distribute list in on the router attached to wan 2 so OSPF won't installed the route to 192.168.10.0 in the local RIB. Note a distribute list won't impact what's in the local OSPF database, but it will impact what OSPF installs in the local routing table.


http://cisco.com/en/US/tech/tk365/technologies_q_and_a_item09186a0080094704.shtml#q12


If both wan links end up on the same router, there's no real way to do this, other than using static routes, or some such.


In the other direction, as the previous poster noted, you are trying to route based on the source address. The only way to do this today is with policy based routing.


HTH...


:-)


Russ

saugatobanerjee Sun, 06/03/2007 - 05:13
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Hi,


What i have gt from question is that u hav source subnets as 192.168.10.0/24 & 192.168.20.0/24. Now u want to send packets to same destination thru both WAN links.


If it is point to point type of network...


then u have define equal cost on both the path, that is the interface on WAN interfaces that you are running OSPF.

OSPF supports load sharing on equal cost paths.


Regards,


Saugato

saugatobanerjee Sun, 06/03/2007 - 05:16
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Hi,


Frgt to mention one thing this will only load share frward traffic.


reverse traffic will not be load shared as your destination subnets are differnt.

Pls note:


As load sharing is by default....


ip load-sharing per destination.

leungcm Sun, 06/03/2007 - 05:41
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Hi,


ok. I would like to split the traffic into two base one destination ip address. e.g.


any ---> WAN 1 ---> 172.16.1.10


any ---> WAN 2 ---> 172.16.1.20


the "traffic to 172.16.1.10" will not go into WAN2 until the WAN1 goes down.


base on above condition, how to config ospf? thanks


best regards



ruwhite Sun, 06/03/2007 - 06:22
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How many routers on the "any" side of this? One, or two? If two, how are they connected?


:-)


Russ

leungcm Sun, 06/03/2007 - 08:22
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Hi,


any means 192.168.0.0/16


best regards


ruwhite Sun, 06/03/2007 - 16:32
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Does it look like the network on the left, or the one on the right, in the attached diagram? Is there one router, two routers, or three routers in this configuration? Where are they?


Russ



Attachment: 
leungcm Mon, 06/04/2007 - 07:24
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Hi,


there is one router on 172.16 segment.


best regards


ryanwhisler Wed, 06/06/2007 - 06:03
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My network looks like the one on the left. The network on the top side of the graphic is 10.10.0.0.


The IP addresses and networks network on other end are as follows:


The router currently labled as 192.168.10.0 is 192.168.136.0/24 and 192.168.20.0 is 192.168.137/24.


Also, the 137/24 is actually a PIX not a router.


The PIX and Router at the bottom of the drawing are connected via ethernet so traffic for either WAN link can travel between the 2 devices in the bottom network to reach each others' networks.


My goal is to setup the routing so that if WAN1 goes down all traffic is moved to WAN2 and vice versa. So if both are up then the traffic is split based on the destination but if one goes down all traffic which is destined for both network can travel either WAN1 or WAN2.

saugatobanerjee Sun, 06/03/2007 - 08:58
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Hi,


under this scenario............ use filters to define this.

Now you can ideally have a access-router behind core WAN1 & WAN routers.


here you can do is put route map on that router for say 172.16.1.10


route-map permit 10

match ip access-list 1

set ip next hop xxx (ip of the WAN1).


Also put a default route for supernet


172.16.1.0/16 towards the WAN2.


So incase WAN 1 fails traffic will flow via WAN2.




leungcm Mon, 06/04/2007 - 07:31
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hi,


if I use the "delay" option and put it one WAN1, the traffic should go WAN2. after that, we use static route point to WAN2 for another host. So,


any --> wan1 --> destination host A (static route)


any --> wan2 --> second destionation host B (OSPF)


is it working?


best regards

ruwhite Tue, 06/05/2007 - 10:46
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If I were going to do this, I would do it all directly, using two static routes on the single router on the 172.16 side of the wan links. If you point two statics at the right routers on the other side of the two wan links, then the OSPF route would still back up the static routes you have configured.


:-)


Russ

leungcm Fri, 06/08/2007 - 07:47
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Hi,


we would like to split the traffic into two, one is voice, other is data (db replication, smtp, www, .... etc)


all the data goes WAN link 1 and voice goes WAN link 2. when the WAN 1 goes down, ospf will route to WAN 2 auto. We do not need to config the alternative static routes for them.


That's why I would like to implement the ospf so that we do not need to config a lot of alternative route.


If you have any comments or suggestion, please advise.


Best regards



Edison Ortiz Sun, 06/03/2007 - 06:44
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sureshkumar.a Tue, 06/05/2007 - 11:28
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how to know from an ip which is the gate way of that network ?plz assist me any one.


thanks

Rahul


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