I am writing in Linux forums after a long time

I have a network in my office (With Linux + Win Desktops, some are thin clients).

I am facing a strange problem.

I am having a dlink hub(8 port) and dlink switch(16 port).

Both are connected with crossover cable.

Machines connected to the hub can ping each other properly.

But when i ping a machine which is connected to a switch i get packet loss.

Also small packet ping is ok, but when i increase the packet size, the data loss occurs

ping -s 40000 <to a switch machine> = loss
ping <to a switch machine> = OK
ping <to a machine in same hub> = Excellent.

Switch to Switch is also OK.

I have changed cross over cable but its the same... And this same structure worked a few days ago fine!

Another hint for me was that, when i connect the cross over cable to the switch, the collision LED on the hub blinks a lot.. Otherwise its off.

Please Help.