TCP/IP frames size

Hi guys,
in an interview the interviewer ask me what is the maximum data that can be transfered by a TCP/IP segment.
Is 1,500 Bytes is the right answer?
Also, can you guys explain about JumboFrames.
what is the exact difference between a regular and jumbo frames.

@lagapides @andrew

That’s a bit of a trick question, because no matter how you answer it, the interviewer can mark your answer as incorrect (I hope the interviewer liked you!). The reason it is tricky, is because the interviewer would have to clarify the following:

  1. Are you asking for the theoretical maximum amount of data?
  2. By “data” are you including or excluding the header overhead?

The theoretical maximum amount of data is 64K (including headers), but you will never see that. The “default” is 1500 bytes, so you answer was a good one, but if by “data” the interviewer means to exclude the TCP and IP headers, then the answer for “default” size would be 1460 bytes (each header is 20 bytes).

Jumbo frames are simply an expansion of how much data can be transmitted between two speakers before an acknowledgement must occur. Once two speakers agree upon what size of MTU (maximum transmission unit) they will use, then they must acknowledge the frame. This acknowledgement takes up time and resources. If the speakers can agree to a higher MTU, say a jumbo frame of 9,000 bytes, then they can transmit 6 times as much information before an acknowledgement must occur. This will drastically improve performance in a high speed network (1 gig or higher usually).

1 Like

That was a good explanation.

I am also little confused the relation between MSS, MTU, Windowsize. Can you please explain how they are interrelated.
How TCP sends the data. It would great if you explain with some example.
thanks again.

Try reading through the troubleshooting here:

1 Like