Network Stats

BSD - netstat

On BSD systems, the netstat(1) command gives statistics for incoming and outbound data on a single network interface identified by the -I interface option; the figures given are the number of packets, the number of bytes, and the number of errors. The -w wait option is used to output the figures every wait seconds.

The following example illustrates the use of netstat - the third and sixth columns give the number of bytes read and written. The figures shown are for a client and server sending data to and from each other across the loopback device, so the amounts read and written are the same, because each packet written by the client will be read by the server, and vice-versa. 

$ netstat -w 1 -I lo0
            input          (lo0)           output
   packets  errs      bytes    packets  errs      bytes colls
         9     0        501          9     0        501     0
         8     0        484          8     0        484     0
         9     0        492          9     0        492     0
         9     0        469          9     0        469     0
^C
$
Graphing this information is a matter of extracting the third and sixth columns, and expressing both as percentages of the highest total so far. Input is shown in blue, output in red.

Note the header mentions the interface in parentheses. If netstat is run for a non-existent interface, the figures are for 'Total'.

Linux - /proc/net/dev

Linux provides stats for network interfaces in the /proc/net/dev file, as demonstrated by the following example : 
$ cat /proc/net/dev
Inter-|   Receive                                                |  Transmit
 face |bytes    packets errs drop fifo frame compressed multicast|bytes    packets errs drop fifo colls carrier compressed
    lo: 1562798    8582    0    0    0     0          0         0  1562798    8582    0    0    0     0       0          0
  eth0:48527843  406919    0    0    1     0          0         0  4935999   51983    0    0    0     0       0          0
$
To graph the amounts of incoming and outbound data, we extract columns two and ten (using a regular expression, as the first field is not space-separated), and express both figures as percentages of the highest total so far. Reads (receive) are shown in blue, writes (transmit) in red.

What to conclude from the network meter

  1. Don't know... It shows activity.