Routers not aware of each other

[Remi Pilon]

I have 2 cisco 2811 2-FE routers, i configured fe0/1 on both routers with different ip addresses and did no shut.

status is up but protocol is down. its like they are not aware of each other, speed and duplex is set to auto.

when plugged into my laptop the interface lights come on but when connected to each other no interface lights.

thanks for the help in advance

[balaji.bandi]

what kind of cable (cross over and straight ?)   - have you connected both the routers with laptop, both the side come up ?

this could be :

1. Cable issue

2. speed Mismatch

3. duplex issue.

[Remi Pilon]

I have just configured speed 100 and duplex full on my interfaces, R1 Ip add 192.168.1.1 255.255.255.0 and R2 Ip add 192.168.1.2 255.255.255.0. and did no shut on both. now only the f light is turning on my cisco 2811 routers. I was just wondering why a cross over cable and a straight through cable can't do the same thing before I go out and buy one. I have a dozen straight through cables.

[liviu.gheorghe]

I would try:

1. chancing the cable

2. using a crossover cable

[Remi Pilon]

Hello all and thank you for the help, I have just configured speed 100 and duplex full on my interfaces, R1 Ip add 192.168.1.1 255.255.255.0 and R2 Ip add 192.168.1.2 255.255.255.0. and did no shut on both. now only the f light is turning on my cisco 2811 routers. I was just wondering why a cross over cable and a straight through cable can't do the same thing before I go out and buy one. I have a dozen straight through cables.

[M02@rt37]

Hello @Remi Pilon 

Please give us IP and Mask of each interfaces. Ensure to use crossover cable.

Thanks.

[Remi Pilon]

Hello all and thank you for the help, i have just configured speed 100 and duplex full on my interfaces, R1 ip add 192.168.1.1 255.255.255.0 and R2 ip add 192.168.1.2 255.255.255.0. and did no shut on both. now only the f light is turning on on my cisco 2811 routers. i was just wondering why a cross over cable and a straight through cable cant do the same thing before i go out and buy one. i have a dozen straight through cables.

[M02@rt37 · Accepted solution]

@Remi Pilon 

When connecting two routers directly, it's essential to use the appropriate cable to establish a proper connection. A crossover cable is required in this scenario because both routers are similar devices, meaning they have the same functionalities. A crossover cable crosses the transmit and receive pairs, allowing the routers to communicate effectively. In contrast, a straight-through cable, typically used to connect devices with different functions (such as a router to a switch), will not achieve the desired connectivity between the routers. If you don't have a crossover cable readily available, you can create one manually if you have spare connectors and a crimping tool. So, you can create a custom crossover cable to facilitate the direct connection between the routers. 

[Remi Pilon]

Hello all and thank you for the help, i have just configured speed 100 and duplex full on my interfaces, R1 ip add 192.168.1.1 255.255.255.0 and R2 ip add 192.168.1.2 255.255.255.0. and did no shut on both. now only the f light is turning on on my cisco 2811 routers. i was just wondering why a cross over cable and a straight through cable cant do the same thing before i go out and buy one. i have a dozen straight through cables.