HTTP Pipelining
HTTP pipelining is a technique used in HTTP protocol to improve the performance of multiple HTTP requests over a single TCP connection. It allows multiple requests to be sent on a single TCP connection without waiting for the corresponding responses.

How HTTP Pipelining Works
HTTP pipelining works by allowing the client to send multiple HTTP requests to the server without waiting for the responses. The requests are sent in a sequential manner, one after the other, on the same TCP connection. The server processes the requests in the order they were received and sends back the responses in the same order.

Benefits of HTTP Pipelining
HTTP pipelining offers several benefits including:

1. Reduced latency: By sending multiple requests on a single TCP connection, the client can reduce the round-trip time required for each request. This leads to lower latency and faster overall performance.

2. Increased throughput: Since the requests and responses are sent over the same TCP connection, there is no need to establish a new connection for each request. This eliminates the overhead of connection setup and teardown, resulting in improved throughput.

3. Efficient resource utilization: HTTP pipelining allows for better utilization of network and server resources. By sending multiple requests on a single connection, the server can process them concurrently, leading to better resource utilization.

Limitations of HTTP Pipelining
While HTTP pipelining offers performance benefits, it also has some limitations:

1. Head-of-line blocking: If a response to a particular request takes longer to process, it can delay the subsequent responses. This is known as head-of-line blocking and can impact the overall performance.

2. Compatibility issues: Not all servers and clients support HTTP pipelining. Some servers may not handle pipelined requests correctly, leading to errors or incorrect behavior. Similarly, some clients may not be able to process pipelined responses correctly.

3. Lack of request prioritization: HTTP pipelining does not provide a mechanism for prioritizing requests. All requests are sent in the order they were issued, regardless of their importance or urgency.

In conclusion, HTTP pipelining allows multiple HTTP requests to be sent on a single TCP connection without waiting for the corresponding responses. It improves performance by reducing latency, increasing throughput, and efficient resource utilization. However, it also has limitations such as head-of-line blocking and compatibility issues.