Method for registering a communication terminal

• US 20040153667A1
• Filed: 05/21/2003
• Published: 08/05/2004
• Est. Priority Date: 05/22/2002
• Status: Active Grant

• Current Assignee: IP Edge LLC
• Original Assignee: Siemens AG
• Inventors: Kim, Peter, Kastelewicz, Georg
• Granted Patent: US 7,610,619 B2
• Time in Patent Office: Days
• US Class Current: 713/201
• CPC Class Codes: H04L 2209/80 Wireless
• CPC Class Codes: H04L 65/1016 IP multimedia subsystem [IMS]
• CPC Class Codes: H04L 9/3213 using tickets or tokens, e.g. Kerberos network architectures or network communication protocols for entities authentication using tickets in a packet data network H04L63/0807
• CPC Class Codes: H04W 12/06 Authentication

Abstract

The invention relates to a method for registering a communication terminal with a service network which organizes a communication service. Within this context, in a preliminary step, a logon IP address which was assigned to the communication terminal when the communication terminal logged onto the access network is received by the service network and is stored therein for the respective user of the communication terminal. When a first registration message sent by the communication terminal is received a token is transmitted to the communication terminal using a transport message, the token having been produced by the service network from the logon IP address and a random number using an encryption method, and token data associated with the token having been stored in the service network. When a second registration message which is sent by the communication terminal and contains the token is received the service network compares the token received, a public identifier and/or a private identifier with stored variables.

Claims

1. A method for registering a communication terminal (UE) with a service network (IMS) which organizes a communications service, where the service network (IMS) is accessed by the communication terminal (UE) using an access network (GPRS) which connects the communication terminal (UE) to the service network (IMS), in which

in a preliminary step, a logon IP address (IP-SRC-UE) which was assigned to the communication terminal (UE) when the communication terminal (UE) logged onto the access network (GPRS) is received by the service network (IMS) and is stored therein for the respective user of the communication terminal,

when a first registration message (SIP Register 1) sent by the communication terminal (UE) is received a token (TOKEN) is transmitted to the communication terminal (UE) using a transport message (SIP 401 UNAUTHORIZED) sent using the logon IP address (IP-SRC-UE), the token (TOKEN) having been produced by the service network (IMS) from the logon IP address (IP-SRC-UE) and a random number (RN) using an encryption method, and token data (RN, IP-SRC-UE, SIP-Public-ID) associated with the token (TOKEN) having been stored in the service network,

when a second registration message (SIP Register2) which is sent by the communication terminal (UE) and contains the token is received the service network (IMS) compares the token received with the token data,

successful registration is identified if the token matches the token data, and

unsuccessful registration is identified if the token does not match the token data.

2. The method as claimed in claim 1, characterized in that

the service network (IMS) stores the token (Token) as token data,

comparison of the received token with the token data stored in the service network involves the received token being compared with the stored token, and

successful registration is identified if the received token matches the stored token.

3. The method as claimed in claim 1, characterized in that

the service network stores the logon IP address (IP-SRC-UE) and the random number (RN) as token data,

reception of the second registration message (SIP Register2) by the service network (IMS) is followed by decryption of the token transmitted with this second registration message,

comparison of the received token with the token data stored in the service network involves the logon IP address (IP-SRC-UE) recovered during decryption being compared with the stored logon IP address, and

successful registration is identified if the recovered logon IP address (IP-SRC-UE) matches the stored logon IP address.

4. The method as claimed in claim 3, characterized in that

the preliminary step involves the logon IP address (IP-SRC-UE), which was assigned to the communication terminal (UE) when the communication terminal (UE) logged onto the access network (GPRS), being assigned to a public identifier (SIP-Public-ID) for the communication terminal (UE) via the service network (IMS),

the recovered logon IP address (IP-SRC-UE) or the token is used to read the public identifier (SIP-Public-ID) which is stored in the service network and is associated with the logon IP address,

reception of the second registration message (SIP Register2) by the service network is followed by comparison of a public identifier contained in this second registration message with the public identifier (SIP -Public-ID) which has been read, and

successful registration is identified only if the public identifier contained in this second registration message additionally matches the public identifier (SIP -Public-ID) which has been read.

5. The method as claimed in claim 3 or 4, characterized in that

reception of the second registration message (SIP Register2) by the service network is followed by comparison of a private identifier contained in this second registration message with a private identifier (SIP-Private-ID) stored in the service network together with the public identifier (SIP-Public-ID), and

successful registration is identified only if the private identifier contained in this second registration message additionally matches the private identifier (SIP -Private-ID) stored in the service network.

6. The method as claimed in one of claims 1 to 5, characterized in that

the service network starts a token timer (TT) associated with the token when the transport message (SIP 401 UNAUTHORIZED) is sent, and

the token is marked as invalid if a predetermined validity period for the token elapses.

7. The method as claimed in one of the preceding claims,

characterized in that

the token (Token) is produced by a switching center (S-CSCF) in the service network (IMS).

8. The method as claimed in one of claims 1 to 6,

characterized in that

the token (Token) is produced by a home location register (HSS) in the service network (IMS).

9. The method as claimed in one of claims 3 to 8,

characterized in that

the token (Token) is decrypted by the switching center (S-CSCF) in the service network (IMS).

10. The method as claimed in one of the preceding claims,

characterized in that

a switching center (S-CSCF) in the service network (IMS) compares the received token with the token data,

the switching center (S-CSCF) identifies successful registration if the token matches the token data, and

the switching center (S-CSCF) identifies unsuccessful registration if the token does not match the token data.