I tried to boot via network.
The flowing error message is occured.
What's wrong with my client system?

===========================
root device (default md0a): ex0
dump device:
file system (default generic): nfs
root on ex0
nfs_boot: trying BOOTP
ex0: device timeout
ex0: device timeout
ex0: device timeout
nfs_boot: timeout...
ex0: device timeout
nfs_boot: timeout...
ex0: device timeout
nfs_boot: timeout...
ex0: device timeout
nfs_boot: trying RARP (and RPC/bootparam)
ex0: device timeout
ex0: device timeout
revarp failed, error=51
=============================

B.G.Jung