HP4000M Switch

[hdemirhan]

My work place have two location. There are two switch Hp4000M and Hp2626. Between the two of them working single mode fiber connections 1G/bits. The Router (Cisco 878 G.shdsl) connected on the HP4000M switch. Sometimes the router ethenet port is blocking. it doesn't answer ping,telnet. I'm connect with console port to router. I see Eth0 is up or atm port is up. I'm doing restart the router but still its'nt answer. When I was disable LX Module on the HP4000M switch the router is working. But the same problem is repeating between three hours. any idea?