The gateway model consists of managing early media sessions using offer/answer exchanges in reliable provisional responses, PRACKs, and UPDATEs.（在会话发起协议（SIP）中引用RFC 3960早期媒体和铃声生成，第3章网关模型，第二段）。
那么根据上面引用的规则，初始INVITE消息所附的报价不构成早期媒体网关模型？
第二段是否与第一段冲突？
An offer/answer exchange that takes place before a final response for the INVITE is sent establishes an "early" media session. Early media sessions terminate when a final response for the INVITE is sent.
第1段不会像第2段那样缩小早期的媒体网关模型。