Specifies the maximum number of bytes that will be allowed on the HTTP start-line. This limitation affects both request-line and status-line.

Since the request-line consists of the HTTP method, URI, and protocol version, this directive places a restriction on the length of a request-URI allowed for a request on the server.

Specifies the maximum number of bytes that will be allowed on an HTTP header field. This limitation affects both request and response header fields.

The size of a normal HTTP header field will vary greatly among different implementations, often depending upon the extent to which a user has configured their browser to support detailed content negotiation.

Specifies the maximum number of bytes that will be allowed on the size and extensions parts of an chunk data that is encoded by Transfer-Encoding: chunked.

According to the HTTP protocol, the size and extensions parts of this kind of data are in this form:

7\r\n; foo=value1; bar=value2\r\n 

Specifies the maximum number of bytes that will be allowed on the data part of an chunk data that is encoded by Transfer-Encoding: chunked.

According to the HTTP protocol, the data part of this kind of data are in this form:

Hello World\r\n 

Specifies the maximum number of bytes that will be allowed on the medatada part of a message that is encoded by Transfer-Encoding: chunked. In fact, these metadata are some Trailer.

Examples:

HTTP/1.1 200 OK
Transfer-Encoding: chunked
Trailer: Expires

9\r\n
Developer\r\n
0\r\n
Expires: Wed, 21 Oct 2015 07:28:00 GMT\r\n
\r\n