CODEWITHSUNDEEP
network-programmingtcp
user3765624
user3765624

Reputation: 31

TCP- Sequence number wrap around

With the Sequence number in the TCP header consisting of 32 bits, Does this value wrap around, if so surely does this not cause problems? Again, if so, would this be a problem on long or fast networks, due to the amount of packets in the pipeline?

Upvotes: 2

Views: 2126

Answers (1)

Brian White
Brian White

Reputation: 8726

No, no problem. In fact, the sequence number could even start near the "end" -- it is initialized with some pseudo-random number for anti-spoofing reasons.

Just think of it as a never-ending counter with only the bottom 32 bits showing. There's no problem because we're not actually counting bytes but just enumerating them so there is no confusion as to what bytes are currently being received.

The only limitation is that you could never have more than 4GiB of traffic "in flight" in either direction.

Upvotes: 4

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