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How can i delay the present of direct connected route?

Hi, I got 2 3550SMI switch interconnecting by Etherchannel. Each 3550 has an uplink to its upstream router (R1-SW1=SW2-R2). R1 and R2 connects to the remote site routers (say R3 and R4).

With EIGRP redistribute connected, R1 update the direct connected network via WAN link A to R3 where R2 does the same thing updating R4 via WAN link B.

The failover is fine after SW2 powered off. However, problem occured when I powered up SW2. During the bootup of SW2, there was carrier signal which brought up the ethernet port of R2 and the direct connected route presented in R2 then updating R4. Some of the traffic had started to come over from R4 via WAN link B to R2 while SW2 is still booting. (or Etherchannel was not yet ready). As a result, workstation connecting to SW1 cannot be reached for those traffic came from R4->R3->SW2.

I have tried to use "carrier-delay 60"on the ethernet port of R2. It seems solve the problem since the direct connected route delay 60sec. Within that 60 sec, no update via EIGRP from R2 to R4 so that all traffic still went through R3->R1. After that 60 sec, SW2 had already bootup and the etherchannel was also ready.

However, i can only do it with C3725 router. I've tried 1750, 25xx, 26xx and 3640-12.3T but the behavior was not expected (route still present immediately after carrier signal detected).

My questions are:

Is that command valid on Eth or FE interface?

Is there any different using that command with diff. router series, eg. ISR (18xx,28xx,38xx)?

Is there any condition that I could make it work? (at least 3725 worked)

Is there any other way to delay the present of that direct connected route?

Thanks.

1 REPLY
VIP Purple

Re: How can i delay the present of direct connected route?

Hello,

instead of the 'carrier-delay' command, you could try to change the EIGRP hello and hold-time intervals (which default to 5 and 15 seconds respectively on broadcast media such as Ethernet), in order to delay EIGRP convergence. So, on your Ethernet interfaces when you use the interface commands:

ip hello-time eigrp x 60

ip hold-time eigrp x 180

the redistributed routes will show up only after 60 seconds, which effectively does the same as the 'carrier-delay'...

Can you try that and see if that works for you ?

Regards,

GP

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