在电信系统中，因此也在IP系统中，终端用户使用E.164号码（或与E.164相关的拨号号码）来识别呼叫的目的地。在IP系统中，当终端用户连接到终端时，该终端用户的E.164名称临时与终端（端点）的IP地址（传输地址）关联。私有编号方案使用类似的安排。本技术报告定义了在互联的IP网络（系统）上查找目的地（端点的IP地址）的要求，用于在IP电话网络上发起或通过IP电话网络传输的呼叫。呼叫的最终目的地可能是IP网络本身或SCN上。在这种情况下，IP地址需要识别SCN的POI。尽管TR定义了E.164号码的要求，但同样的原则也适用于任何可能引入电话的新命名系统。 TR负责获取路由呼叫和服务控制消息（包括数据库查询）以及媒体流数据包的IP地址（或联系地址）。TR涵盖了对E.164、国家和专用网络内所有类型号码结构的呼叫要求，并包括对号码便携性、移动性和漫游的支持。

In telecommunication systems and therefore also in IP systems E.164 numbers (or dialled numbers related to E.164) are used by end users to identify the destination of a call. In IP systems, when an end user is attached to a terminal, the E.164 name of this end user is temporarily associated with the IP address (transport address) of the terminal (endpoint). Private numbering schemes use similar arrangements. This technical report defines the requirements for finding destinations (IP addresses of endpoints) on interconnected IP networks (systems) for calls originating on or transiting via IP telephony networks. The final destination of the call may be either the IP network itself or on the SCN. In this case the IP address needs to identify the POI to the SCN. Although the TR defines requirements for E.164 numbers, the same principles could be applied to any new naming system that might be introduced for telephony. The TR deals with obtaining IP-address (or Contact Addresses) for routing Call and Service Control Messages (including database queries) and Media Stream Packets. The TR covers the requirements for calls to all types of number structures within E.164, national and private networks and includes the support of number portability, mobility and roaming.