In order to determine the network speed on Solaris,
First, figure out the names of the network interfaces with ifconfig -a
Then for each network device, issue the command…
# ndd /dev/bge0 link_speed
1000
You can also determine other aspects of the connection with…
# ndd /dev/bge0 link_duplex
2
# ndd /dev/bge0 link_autoneg
1
# ndd /dev/bge0 link_status
1