problem reduce Rip timers

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May 23rd, 2008
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Hello

MI ha a important problem . I lost conectivy . My situation is as follows:


I have a Central router 7200 which collects 600 remote routers. He reduced to half from (20 to 10 sg) rip the time of updates.

Old tiemrs: 20 40 40 40

Current timers: 10 20 20 20


The effect is that the remote left to learn the routes which distributes the central . The only sends it that this is the default route that learns via OSPF. Thiscentral is the ASBR of one NSSA. It is possible that is losting defCte default route by learnt by ospf and then redistributed by rip to remote routers by some sort of bug.

thanks

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Giuseppe Larosa Fri, 05/23/2008 - 01:57
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Hello,

I'm not sure to have understood so I may be wrong.

On what side have you changed the RIP timers ?

If you changed on the remote side only of course the remote router will not install the default route for the timers mismatch : the central site will send its update every 20 seconds that is just the time the remote waits before considering to remove the route.


you need some margin to be able to have it to work: use 10 30 30 30 on the remote instead.


the side with the higher timers values will install the routes coming from the other side.


Look at the following link:



http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_rip.html#wp1012751


timers basic (RIP)

To adjust Routing Information Protocol (RIP) network timers, use the timers basic command in router configuration mode. To restore the default timers, use the no form of this command.


timers basic update invalid holddown flush



If you changed only at the Central site it is easier to recover just use the old values.


Be aware that by reducing the timers you will increase the load on the cpu on the central site router so verify what is the current cpu usage to see if there is space for this change. 600 neighbors are quite a lot.


hope to help

Giuseppe

TelekoCaja Fri, 05/23/2008 - 03:56
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I have changed the router timers both, central and remote routers. But I look at the CPU core router (show process cpu ) and I don't advertise high levels cpu

Giuseppe Larosa Sun, 05/25/2008 - 02:44
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Hello,

sorry for having thought you had changed only on one side but it was not clear to me what you had done.

if RIP timers are the same it should work but for the hub router the timers' reduction has a greater impact.

How many RIP neighbors have you got on the hub router ?

What are the symptoms ? do you miss the hub router's routes on some of the remote site routers or all of them are receiving nothing ?

Does the hub router receive the routes of all the spoke routers ?

The original ratio of the timers is 3 so you could try using 10 30 30 30 to see if anything changes.


You said that the hub router is an NSSA ASBR router sending out a default route in RIP to the remote routers ?

is this correct ?


hope to help

Giuseppe

TelekoCaja Tue, 06/03/2008 - 13:17
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the hub has about 1200 routes and 600 neighbours. I miss sometimes some routes of the hub router. The hub is a

NSSA ASBR router sending out a default route in RIP to the remote routers

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