monitoring and reporting traffic

Hi all,

I'd like to know what are the best tools in Linux for generating
traffic reports for a private subnet. Currently we are using
traffic-vis, but the results are less than satisfactory.

To be concrete, the private subnet (250+ users) is attached to our
public LAN through a gateway (a Linux box with two ethernet cards).
We assign traffic quotas to our users, but only for external traffic
(i.e., traffic going out of or coming into our public LAN from the
Internet through our router) with iptables on the gateway. That
traffic is the one we are monitoring with traffic-vis.

(To be even more concrete, we collect data on the external interface
of the Linux gateway with
traffic-collector -p -i eth0 -f "dst net 192.168.1 \
and src net ! <LAN>" -s
<datafile>
and similarly for outgoing traffic. We then process the data with
traffic-sort, etc.)

Truth is, we are used to the superb traffic reports we generate for
the public LAN from netflow data from our Cisco router with
AdvnetNet's ManageEngine NetFlow Analyzer. Compared to that,
traffic-vis is just a toy. (On top of that, it's not currently being
maintained so it's not going to improve any time soon...)

So, we'd be grateful to know of other, hopefully better, traffic
monitoring tools in Linux, which can generate decent traffic reports
for a private subnet with a Linux gateway.

Any help will be greatly appreciated. Best....................