CODEWITHSUNDEEP
http
Ramy Al Zuhouri
Ramy Al Zuhouri

Reputation: 21966

Why is HTTP protocol stateless if it can deal with persistent connections?

The HTTP protocol is stateless, but I found this on the Kurose-Ross book: 

The default HTTP method is with persistent connections and pipeling.

This means that it can handle multiple requests, so it keeps opened the socket of a client that wants to ask multiple requests.Is that true? If yes, why is HTTP protocol considered stateless?

Upvotes: 6

Views: 2482

Answers (1)

eis
eis

Reputation: 53482

HTTP persistent connections relate to TCP connection being left open. HTTP operates on top of TCP - so TCP can be connected and/or stateful whereas HTTP would not. TCP is just the transport for HTTP.

If you look at the OSI model, you can see that TCP is on layer 4 (transport), whereas HTTP is on layer 7 (application). HTTP is not tied to TCP and could use other ways of transport too - as a protocol, it is not "inheriting" features from TCP.

(Note also that the persistent connection is not really persistent for a very long time. For Apache 2, it is open only for 5 seconds per default, and "According to RFC 2616 (page 46), a single-user client should not maintain more than 2 connections with any server or proxy".)

Upvotes: 6

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