Address definition for IP telephony services

1. A method for establishing a telephone call, comprising: receiving telephone number information that includes a telephone number and a nature of address indicator;

mapping the telephone number information to a session initiation protocol format to form a session initiation protocol message that includes a nature of address indicator;

establishing the telephone call based on the nature of address indicator in the formed session initiation protocol message; receiving a session initiation protocol message that includes a nature of address indicator;

mapping the received session initiation protocol message to a call establishment request of a different format, where the call establishment request includes nature of address indicator and where the different format includes one of a signaling system 7 format, an integrated services digital network format, an integrated services digital network user part format, or a channel associated signaling format; and establishing a second telephone call based on the nature of address indicator in the call establishment request.

2. The method of claim 1 , where the telephone number information further includes a numbering plan indicator, and

where the mapping the telephone number information to a session initiation protocol format forms the session initiation protocol message to include a numbering plan indicator.

3. The method of claim 2 where the establishing is further based on the numbering plan indicator in the session initiation protocol message.

4. A method for establishing a telephone call, comprising:

receiving telephone number information that includes a telephone number and a numbering plan indicator;

mapping the telephone number information to a session initiation protocol format to form a session initiation protocol message that includes a second numbering plan indicator; establishing the telephone call based on the numbering plan indicator in the formed session initiation protocol message;

receiving a session initiation protocol message that includes a numbering plan indicator; mapping the received session initiation protocol message to a call establishment request of a different format, where the call establishment request includes a numbering plan indicator and where the different format includes one of a signaling system 7 format, an integrated services digital network format, an integrated services digital network user part format, or a channel associated signaling format; and establishing a second telephone call based on the numbering plan indictor in the call establishment request.

5. The method of claim 4 , where the telephone number information further includes a nature of address indicator, and where the mapping the telephone number information to a session initiation protocol format forms the session initiation protocol message to include a nature of address indictator.

6. The method of claim 5 where the establishing is further based on the nature of address indicator.

7. A system comprising:

means for receiving telephone number information that includes a telephone number and a nature of address indicator;

means for mapping the telephone number information to a session initiation protocol format to form a session initiation protocol message that includes a nature of address indicator;

means for establishing a telephone call based on the nature of address indicator in the formed session initiation protocol message;

means for receiving a session initiation protocol message that includes a nature of address indicator;

means for mapping the received session initiation protocol message to a call establishment request of a different format, where the call establishment request includes a nature of address indicator and where the different format includes one of a signaling system 7 format, an integrated services digital network format, an integrated services digital network user part format, or a channel associated signaling format; and

means for establishing a second telephone call based on the nature of address indicator in the call establishment request.

8. The system of claim 7 further comprising:

means for translating a numbering plan indicator included in the received session initiation protocol message to cause the call establishment request of the different format to include a numbering plan indicator.

9. A system comprising: means for receiving telephone number information that includes a telephone number and a numbering plan indicator;

means for mapping the telephone number information to a session initiation protocol format to form a session initiation protocol message that includes a numbering plan indicator;

means for establishing the telephone call based on the numbering plan indicator in the formed session initiation protocol message;

means for receiving a session initiation protocol message that includes a numbering plan indicator;

means for mapping the received session initiation protocol message to a call establishment request of a different format, where the call establishment request includes a numbering plan indicator and where the different format includes one of a signaling system 7 format, an integrated services digital network format, an integrated services digital network user part format, or a channel associated signaling format; and

means for establishing a second telephone call based on the numbering plan indicator in the call establishment request.

10. The system of claim 9 further comprising:

means for translating a first nature of address indicator included in the received session initiation protocol message to cause the call establishment request of the different format to include a nature of address indicator.