Workstations in B301 unable to retrieve IP from DHCP server

Workstations in B301 connect to the plugins underneath the floor with Cat 5 cables.  The 3Com 4400 in the room is dead and is now replaced with a H3C 5120, which runs at 1Gbps.  The Cat 5 cables render the network incapable of running @ 1Gbps, even though the signal lights on the H3C are all green.  Only part of the workstations can retrieve their IPs from the DHCP server.

When the Cat 5's are replaced with Cat 6's, workstations can run normally @ 1Gbps.

Solution:  To prevent the hassle of replacing all the Cat 5's, all ports on H3C are configured to run @ 100Kbps using the following commands:

> sys
> int gig 1/0/n
> speed 100