Cable link down

We are unable to ping from Sun Ultra 60 to Ultra 10 machine and vice versa. We are getting an error message Cable Link Down ?. It was working fine.
Troubleshooting steps taken.
1) Changed the IPaddresses on both machines 192.168.10.10 and 192.168.10.20. These machines connected through 8 port switch.

2) Brought down the hme0 and brought up the hme0 on both machines.

3) mentioned the entry of host name in /etc/hosts in both machines

4) performed sysunconfig as well and both are piniging to loop back address.

5) Re-installed the OS as well at last.

Can any body suggest to come out of this.

Had an almost same issue at work today, turned out to be the cables. Check "dladm show-dev" and "ndd -get /dev/hme link_status".

Before doing ALL THOSE, did you check if the port was blinking and nothing wrong in the cards by connecting your notebook directly and do a ping test. If both systems are having the same issue, could it be your network?