2.2.1.4.3 BurstBW

When used in a request, this token specifies a transmission rate, in bits per second, that the client requests the server to use when transmitting the amount of multimedia data that is specified by the BurstDuration (section 2.2.1.4.4) token. The client that sends the request is usually an intermediate device that is relaying the request for another client. The AccelBW (section 2.2.1.4.1) token, if specified, is the token provided by the original client. The BurstBW token specifies the transmission rate that is requested by the intermediate device.

When used in a response, this token specifies the transmission rate, in bits per second, that the server intends to use when transmitting the amount of multimedia data that is specified by the BurstDuration token of the server.

The BurstBW token is defined only for servers that have a version that is greater than or equal to 5.0 (as specified by the server in the Server header), and only for clients that have a version that is greater than or equal to 9.0 (as specified by the client in the User-Agent header).<19>

The value MUST be an integer in the range from 0 through 4,294,967,295. If the value is 0, then the token is ignored.

The syntax of the BurstBW token is defined as follows.

 BurstBW       = "BurstBW=" 1*10DIGIT

Although not required, the BurstBW and BurstDuration tokens are typically grouped together, as shown in the following example.

 Pragma: BurstBW=1048576, BurstDuration=5000