Two routers linked via crossover?

coax31

I have a 3600 and a 1720 hooked together via crossover cable to their ethernet ports. The IPs assigned are 172.16.20.1 and 172.16.20.2 with a subnet mask of 255.255.255.0 full duplex or half I cannot ping ether one in IOS? What am I doing wrong? I am getting link lights.

miller811

Are the interfaces shutdown?

techster79

Did you run no shut on the interfaces? What does the show interface command display on each router? How is the cross-over cable wired? If the interfaces are up and up, what does the sh cdp ne command tell you?

coax31

One is up and up the other is up and down, I did a no shut on both. Just a standard CAT5 crossover. I will try the CDP command

coax31

sh cdp neighbors shows no neighbors? Looks like i saw two green blibs on the 3600 E0/0 port but than no lights, bad port maybe?

r_durant

Are they both Ether interfaces? Or a FastEther and an Ether?

Try them both at 10Mbps/half...

coax31

Both Ether and tried both on half duplex and full duplex no luck, used a 1900 between the routers with straight through cables now they can see each other.

r_durant

Have you tried them at 10Mbps? Unless they are 10/100 ports??

Have you verified that the cable works on other devices? Two PC's back-to-back?

mgeorge

Sounds like a duplex issue, 1700's have 10/100 FastEthernet ports.

Most likely your 3600 has a NM-1E2W (because they are cheep, 37 dollars cheep or cheeper lol)

manually set both speed and duplex on the routers to 10Mb Half

tech-airman

coax31 wrote:

I have a 3600 and a 1720 hooked together via crossover cable to their ethernet ports. The IPs assigned are 172.16.20.1 and 172.16.20.2 with a subnet mask of 255.255.255.0 full duplex or half I cannot ping ether one in IOS? What am I doing wrong? I am getting link lights.

coax31,

What exact "3600" model do you have?