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New Member

I need help

My equipment Config and connection:

3640 Router with the following config.

Serial1/0 (connected with leased line)

Serial1/1 (connected with leased line)

Serial1/2 (connected with leased line)


3550 & 2950 Switches

Vlan 1 add to 7 (gateway

3508 Switch (gateway

PIX Firewall (gateway

2950-24 Switch (

This is the scenario:

The 3550G-48 & 2650G-48 is connected to 3508G with fiber optic gigastacking. Ethernet0/0 of the router connected to one port of the 3550 switch. The 2950-24 (which have vlan for DMZ, Inside and Outside network) which connected to PIX Firewall is connected with Cat5 cross cable in 3550 switch. Now the problem that I encouter is that I got a unstable comuunication between my location to the remote area. But when I disconnect the cross cable between 2950-24 to 3550g-48,I get an stable connetion. Do I miss configuration or maybe my configuration is wrong.

Thanks a lot.


Re: I need help

The addresses on your serials are all in the same network. Since I cant see how that would ever work I assume thats a typo.

Is the 3550 routing? What routing protocols are you running and where? Are the 3550 and 2650 each directly connected tot he 3508 or daisy chained?

What do you mean by unstable? Certain destinations cannot be reached? Circuits go down? Who cant reach who and where are they in your topology?

New Member

Re: I need help

thank you for the response..

unstable means, when I try to ping the other location it keeps giving on and off connection.. while the other location is giving me stable connections.

In 3550 there is no routing, my routing is in my 3640 router.

Protocols IGRP

3550 and 2650 directly connected to 3508 via 1000baseSX stacking. and one ethernet port from 3640 router connected to one of 3550 switch. I leave the switch on default config. I didn't touch anything yet because am still learning it. I just try to follow what I read in the book..

thank you

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