The HTTP version MUST be 1.1.

Each message includes a number of fields in the HTTP message header. Some of them are standard fields, as specified in [RFC2616], that are required to take on specific values, whereas others are new fields defined by [MC-BUP]. The fields MUST follow the rules defined in [RFC2616] section 4.2.

Each request message MUST be sent as an HTTP extension-method (as discussed in [RFC2616] section 5.1.1) called BITS_POST.

Each response message MUST follow the rules defined in [RFC2616] section 6.

The size of the value of a header field SHOULD NOT be more than 4 kilobytes.<2>

Each response message MUST include a BITS-specific HTTP message header field named BITS-Package-Type with the field value Ack.