Monitor bitcoind node traffic? I was wondering how I would go about measuring the traffic being used on my network for the bitcoind node I am running. It's running  on the standard 8333 port, using linux as the OS.

I was looking at iftop which seems to be a tool for doing what I want to do, but I am specifically looking to only monitor traffic associated with the bitcoind node.

Basically I'm trying to see if my implementation of a QOS for the node is working properly.
The RPC interface has a command getpeerinfo which will give a breakdown of upload and download metrics per connected peer. 

  {  
    .. 
    "bytessent": 67619177,  
    "bytesrecv": 47229533,  
    "conntime": 1446238156,  
    ..  
  }


Totals for the session for all peers are available with getnettotals. 

{
  "totalbytesrecv": 3664310320,
  "totalbytessent": 619085268,
  "timemillis": 1446521403149
}


vnstatis an external tool which will do system-wide monitoring and statistics collection over extremely long time periods. There is no per process breakdown, but it's a good thing to have around for a global view anyway. 

eth0:
       Oct '15     70.88 GiB  /    2.65 GiB  /   73.53 GiB
       Nov '15     19.61 GiB  /  976.31 MiB  /   20.57 GiB  /  288.12 GiB
     yesterday      9.40 GiB  /  471.48 MiB  /    9.86 GiB
         today      1.13 GiB  /   66.35 MiB  /    1.20 GiB  /    8.49 GiB