Difference between Persistent and Non-Persistent Connections
| Persistent HTTP | Non-Persistent HTTP |
|---|---|
| The server leaves the connection open after sending a response. | Requires 2 RTTs per object. |
| Subsequent HTTP messages between the same client/server are sent over an open connection. | OS overhead for each TCP connection |
| The client sends requests as soon as it encounters a referenced object. | Browsers often open parallel TCP connections to fetch referenced objects. |
| As little as one RTT for all the referenced objects. | Here, at most one object can be sent over one TCP Connection. |
HTTP Non-Persistent & Persistent Connection | Set 1
The Hypertext Transfer Protocol (HTTP) is an application-level protocol that uses TCP as an underlying transport and typically runs on port 80. HTTP is a stateless protocol i.e. server maintains no information about past client requests.