ISO/IEC 22535:2009规定了在公司电信网络（CN）内通过会话启动协议（SIP）进行“QSIG”隧道传输。 QSIG通过采用SIP的公共IP网络的隧道传输不在ISO/IEC 22535:2009的范围内。然而，当与其他相关功能（例如地址转换、安全功能等）一起部署时，本国际标准中规定的功能原则上适用于此类场景。 ISO/IEC 22535:2009适用于任何可以充当采用QSIG的PISN和采用SIP的企业IP网络之间的网关的互通单元，QSIG在SIP请求和响应中进行隧道传输。

ISO/IEC 22535:2009 specifies tunnelling of "QSIG" over the Session Initiation Protocol (SIP) within a corporate telecommunication network (CN). The tunnelling of QSIG through a public IP network employing SIP is outside the scope of ISO/IEC 22535:2009. However, the functionality specified in this International Standard is in principle applicable to such a scenario when deployed in conjunction with other relevant functionality (e.g. address translation, security functions, etc.). ISO/IEC 22535:2009 is applicable to any interworking unit that can act as a gateway between a PISN employing QSIG and a corporate IP network employing SIP, with QSIG tunnelled within SIP requests and responses.