How to see network traffic per interface in FreeBSD?

Question

want to see an amount of traffic passed through interface since boot. It's an ISPManager VDS with FreeBSD 8.0, and

ifconfig -L epair521b -B

does nothing.

Want to have output like Linux's ifconfig:

lo Link encap:Local Loopback
...

RX bytes:6642443661 (6.1 GiB) TX bytes:6642443661 (6.1 GiB)

Answer 1

Reading file /usr/local/share/munin/plugins/if_ (in port sysutils/munin-node) I see it's using the following command line to achieve just that :

/usr/bin/netstat -i -b -n -I $INTERFACE

PS: that file also contains a warning that those are 32 bit counters; some years ago I RTFS and verifier that's because it's easier to update atomically; I didn't verify if it's the same on the (more recent) amd64 platform though.