As mentioned before, io-pkt* is the framework used to connect drivers and protocols. In order to troubleshoot this, use the pidin command:
$ pidin -P io-pkt-v4-hc mem
The output should be something like this:
pid tid name prio STATE code data stack
126996 1 sbin/io-pkt-v4-hc 21o SIGWAITINFO 872K 904K 8192(516K)*
126996 2 sbin/io-pkt-v4-hc 21o RECEIVE 872K 904K 8192(132K)
126996 3 sbin/io-pkt-v4-hc 21r RECEIVE 872K 904K 4096(132K)
126996 4 sbin/io-pkt-v4-hc 21o RECEIVE 872K 904K 4096(132K)
126996 5 sbin/io-pkt-v4-hc 20o RECEIVE 872K 904K 4096(132K)
126996 6 sbin/io-pkt-v4-hc 9o RECEIVE 872K 904K 4096(132K)
libc.so.4 @b0300000 444K 16K
devnp-abc100.so @b8209000 40K 4096
lsm-qnet.so @b8214000 168K 36K
You should see a shared object for a network driver (in this case the fictitious devnp-abc100.so). You can also use the pidin ar and ifconfig commands to get more information about how the networking is configured.