摘要 |
<p>Apparatus for resolving a local TEL Uniform Resource Identifier to a service Uniform Resource Identifier for routing a message over an IP-based communication system. The apparatus comprises first processing means (2) for constructing a domain name system query string incorporating digits of the TEL Uniform Resource Identifier and a Context Identifier associated with the TEL Uniform Resource Identifier, and second processing means (3) for performing a Domain Name System lookup using said domain name system query string and for receiving in response said service Uniform Resource Identifier</p> |