Connections that allow a client and server to maintain an open TCP connection for multiple requests and responses.
Instead of opening a new connection for each request, which can incur overhead in terms of time and resources, a persistent connection keeps the connection open after the initial request is made, allowing subsequent requests to be sent over the same connection.
Pros
- Reduced overhead for multiple requests as no new connections need to be established for each request.
- Better scalability for systems with high traffic or many concurrent users by the reduced overhead.
- Can enhance efficiency by using pipelining, such that each request does not need to wait for each response.
Cons
- Requires resources to keep connections open.
- Can be complex to implement.
- Can waste resources be keeping idle connections open.
Implementations
- HTTP/1.1