Editors note the above statement conflicts with the

Info icon This preview shows pages 26–28. Sign up to view the full content.

View Full Document Right Arrow Icon
Editor's Note: The above statement conflicts with the use of GIBA as an allowed mechanism for UMTS access. The generation of the authentication vector AV that includes RAND, XRES, CK, IK and AUTN shall be done in the same way as specified in TS 33.102 [1]. The ISIM and the HSS keep track of counters SQN ISIM and SQN HSS respectively. The requirements on the handling of the counters and mechanisms for sequence number management are specified in TS 33.102 [1]. The AMF field can be used in the same way as in TS 33.102 [1]. Furthermore two pairs of (unilateral) security associations (SAs) are established between the UE and the P-CSCF for each registered contact. The subscriber may have several IMPUs associated with one IMPI. These may belong to the same or different service profiles. Only two pairs of SAs shall be active between the UE and the P-CSCF for each registered contact. These two pairs of SAs shall be updated when a new successful authentication of the registered contact of for the subscriber has occurred, cf. clause 7.4. NOTE: An authenticated emergency registration creates a separate registered contact from a normal registration and will therefore have two separate pairs of (unilateral) SAs for the emergency registration. The same applies when multiple registrations by the same UE are used using the Outbound mechanism according to TS 24.229 [8]. It is the policy of the HN that decides if an authentication shall take place for the registration of different IMPUs e.g. belonging to same or different service profiles. Regarding the definition of service profiles cf. TS 23.228 [3]. 6.1.1 Authentication of an IM-subscriber Before a user can get access to the IM services at least one IMPU needs to be registered and the IMPI authenticated in the IMS at application level. In order to get registered the UE sends a SIP REGISTER message towards the SIP registrar server i.e. the S-CSCF, cf. figure 1, which will perform the authentication of the user. The message flows are the same regardless of whether the user has an IMPU already registered or not. 3GPP 3GPP TS 33.203 V12.67.0 (2014-0609) 26 Release 12
Image of page 26

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Figure 4: The IMS Authentication and Key Agreement for an unregistered IM subscriber and successful mutual authentication with no synchronization error The detailed requirements and complete registration flows are defined in TS 24.229 [8] and TS 24.228 [11]. SMn stands for SIP Message n and CMm stands for Cx message m which has a relation to the authentication process: SM1: REGISTER(IMPI, IMPU) In SM2 and SM3 the P-CSCF and the I-CSCF respectively forwards the SIP REGISTER towards the S-CSCF. After receiving SM3, if the IMPU is not currently registered at the S-CSCF, the S-CSCF needs to set the registration flag at the HSS to initial registration pending. This is done in order to handle UE terminated calls while the initial registration is in progress and not successfully completed. The registration flag is stored in the HSS together with the S-CSCF name and user identity, and is used to indicate whether a particular IMPU of the user is unregistered or registered at a particular S-CSCF or if the initial registration at a particular S-CSCF is pending. The registration flag is
Image of page 27
Image of page 28
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern