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OK, this might be a really stupid question, but...

I'm building a web app that utilises websockets. There's fairly rapid messaging going on, so I've been taking a look at the network traffic with wireshark, to see if there's any way of reducing the amount of data we are sending over the wire, and hence costs.

A typical message has approx 150 byte data payload, and according to wireshark the lower layer stuff takes up about: Ethernet: 14 bytes IP: 20 Bytes TCP: 20 Bytes

My question is, are these network headers included in data transfer calculations? What about TCP ACK messages? (another 54 bytes according to wireshark)

This may seem petty, but because we have so much messaging going on, and because the payload is a similar size to these headers, it's significant.

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I would guess most people are going to be size of the IP packet. Since pretty much anything in the layer 2 headers is stripped when the packet crosses a router. – Zoredache Sep 7 '12 at 16:40
up vote 1 down vote accepted

Generally, bandwidth is measured at the IP level. So the Ethernet header does not count, but the IP and TCP headers do. TCP ACK messages are IP packets, so they count too.

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Thank you for clearing that up! – UpTheCreek Sep 7 '12 at 18:44

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