Accounting packets on the fly

Have you ever quickly needed to see how much traffic a host is sending/receiving or how much traffic is in a flow between hosts. IP accounting can easily provide the amount of packets and data for each source/destination pair.

By enabling the following under the interface:
R4#interface fa0/0
ip accounting output-packets

After a couple minutes, you should get a quick idea of the data flows

R4#sh ip accounting output-packets
Source          Destination     Packets  Bytes    2394     1410785    5119     6976939    662      194296   124      15048