According to a computation I did on the data from ifconfig, my ethernet connection between my router and computer averages 1298 bytes/packet for TX (close to the MTU of 1500) and only 131 bytes/packet for RX. What could cause such a large discrepancy in the average TX vs. RX packet sizes?

  • The question is on-topic since it's about understanding the output of a Unix command (@ilkkachu). But, as roaima notes, why are you comparing the color of apples and oranges? And what kind of traffic does this network interface see? (E.g. if most of that traffic is then going through a DSL line, its bandwidth is going to be pretty asymmetric.) – Gilles Apr 3 '17 at 21:54

One possibility is that if you are sending data out predominantly, most of the packets coming back to your system will be ACKs, and those are going to be much smaller than the PUSH you're sending.

  • This is true. I am sending more total packets out than in. – Geremia Apr 4 '17 at 20:30

It's very difficult to say why the difference. Obviously, you are sending more packets than you're receiving, so:

  • Do you use Dropbox, or Box, and is there quite a bit of syncing going on from your host to the service?
  • Are you running a server (Plex? HTTPd?) that other people might be downloading/streaming data from?
  • Maybe your host is compromised and participating in a bot net.

If you really want to know, you should look at tshark/wireshark/tcpdump. Linux Journal had a tutorial on tshark a while back. These tools will allow you to examine the packets going in and out of your system, and will help you determine the source and destination as well as the payload.

That should put you well on your way to actually finding out what's causing the TX/RX asymmetry.

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