Router failover

Unanswered Question
Nov 6th, 2007

hi guys, i m faced with quite a common problem but still need ur help in it, its a scenario of a small ISP providing links to customers, not all of our customers have routers so mostly they connect their lan directly with the ISP which in turns does static routing and nating for them (i know its kinda mess, its being redesigned ), they have 2 routers each connected to a different ISP, they want router A to be the primary router and router B to be backup, they have these constraints

1) cannot use bgp

2) cannot use HSRP/VRRP the reason is because its not the proper lan scenario they are kinda directly connected to the primary routerA, if you are still not getting the design so kindly leave it and tell me how to configure my routers so that the traffic is ROUTED via routerB if the WAN link on serial 0/0 on router A fails, i have heard something SLA but i dont know how much its use of here, we can use any routing protocol to get this objective except BGP, so kindly guide me through, i will highly appreciate if u can tell me wat configuration i need to do

my simple design

RouterA --> serial 0/0 connected to WAN

RouterA --> fas 0/0 connected to clients

same with router B, kindly tell me how to configure it


I have this problem too.
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cdusio Tue, 11/06/2007 - 14:10

how are they connected to router A directly?

Is there a siwtch module in it?

SLA would allow you to generate default routes based upon availability but that doesn't ultimately solve your problem.

What you MUST do on the LAN is make it so that both routers are on the same inside network. You must either use HSRP or some other method to acheive gateway redundancy. If not, the best you can do is use object tracking, redistribute that route into a dymanic routing protocol that both your rotuers are using and make sure the second router has a higher metric for the default route. If the primary route goes away, the second router will advertise the route to the first router on the ethernet interface. then you will get sent out router 2.

It's not nearly as efficient as using HSRP and tracking and it doesn't take into account if Router a fails completely.



illusion_rox Wed, 11/07/2007 - 02:55

both routers are on the same inside network, router A ip is whereas router B is, if possible can u give me the sample configuration of object tracking of my case coz i wasnt able to understand it from cisco doc,

1 thing more sir, do u have any working experience on ACS 3.3 ? can u tell me how to delete log files (*.csv), i m using the software version of it and running under windows 2000 server



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