The type of connection that is kept open after an http request to the server.
persistent
udp
tcp
smtp
non-persistent

Persistent

Explanation:

 Persistent is the type of connection in the hyper text transfer protocol (HTTP) that act as communication channel in the network. It basically remain open after HTTP request or response to the server.

Persistent also maintain the HTTP connection and prevent it from the timing out with the help of transmission control protocol packets.

In the persistent connection, after request has been send TCP connection is leave by the server. Therefore, the request can be easily send between the similar server and client.