Computer Network

Question

I know I shouldn't be asking this but still:

Window size is 16 bits in TCP so maximum possible value is

2^16=65535 bytes.

Why bytes not bits?

Comments

Actually, the maximum possible value of the window size in TCP is not 2^16 as the options field can be utilized to extend the window size

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No, buddy my question was why 65K bytes, not bits?

Answer 1

Because TCP is a byte stream protocol.

Sender and receiver are under the abstraction that they are writing and reading to some byte stream that has been established between them by TCP. So, every transmission and reception is in terms of bytes not bits.

Comments

But in every other protocol also which are not byte stream , if a field is given to be n bits long then maximum possible size is 2^n bytes.

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If some field is n bits long, it means it can denote 2^n distinct sequences or identifications. It depends on our implementation whether we use it to denote 2^n bits, bytes, Kbytes or any other quantum. Since most of our data is interpreted in terms of bytes and we consider byte as the building block of logical data (not electronic) so we use bytes instead of bits. Bits are significant at the physical layer where we are concerned about the actual transmission of electronic signals.