Dr Moazzam Tiwana

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  • IP Multimedia Subsystem (IMS) Security Challenges

    Security and information protection is the core of all computer networks and communication systems. The convergence of fixed-mobile and voice-data networks has opened the door for the innovative and fancy next generation services and applications like integrated multimedia services, combining web browsing, email, instant messaging, presence, VoIP, video conferencing, application sharing, telephony, unified messaging, multimedia…

    August 23, 2021
  • 5G Vs WiFi – Convergence or Competition

    Guest post by Dr. Rizwan Ghaffar (linkedin) With the 5G deployment spreading rapidly, there is a question of what would be the future of Wi-Fi in the world connected by 5G. In my opinion, Wi-Fi and WWAN (wireless wide area networks) will continue their convergence/competitive journey along the road. They will coexist and play an…

    August 15, 2021
  • Question: From the perspective of UE why 5G is more secure than 2G/3G/4G?

    Answer: The 2G GSM systems were the first digital systems that performed the authentication of subscriber. The mobile was assigned a temporary identifier after the authentication so that it does not has to send the mobile subscriber’s permanent identity ‘IMSI’ on the air interface. And the voice was encrypted. However, 2G systems suffered from two…

    August 14, 2021
  • IMS Procedures Tutorial

    Any discussion of IMS protocols must start with a dialogue describing the procedures being implemented. It is important to note that there is no “one size fits all” procedural flow; IMS in LTE offers a lot of flexibility to both network equipment manufacturers and network operators. Note that the processes described here are strictly from…

    August 10, 2021
  • 1. IMS Procedure: Public Data Network (PDN) connectivity

    As in legacy 3GPP technologies, the UE starts connection by issuing a Radio Resource Control (RRC) Connection Request. Note that while either the UE or the network can trigger the connection request, it is always initiatedby the UE. This request includes both the UE identity information and the call establishment cause (i.e.Mobile Originating Signaling or…

    August 10, 2021
  • 2. IMS Procedure: Authentication

    Now that NAS signaling is established, the network initiates an Authentication Request or challenge. Once the UE’s Authentication Response is deemed valid, the network sends a NAS Security Mode Command. Note that while neither the Authentication Request nor the Authentication Response is integrity-protected, the Security Mode Command is protected. The UE then sends a Security…

    August 10, 2021
  • 3. IMS Procedure: Bearer Setup and EPS Attach

    At this point, additional radio bearers must be set up. The network sends an RRC Connection Reconfiguration to activate the EPS bearer. The UE confirms successful completion with an RRC Connection ReconfigurationComplete message and then finalizes the Attach procedure and accepts the activation of the EPS bearer.It should be noted that the way a default…

    August 10, 2021
  • 4. IMS Procedure: P-CSCF Discovery

    Before sending any Session Initiation Protocol (SIP) requests, the UE must perform “P-CSCF Discovery”, the process of identifying (by address) the correct Proxy-Call Session Control Function (P-CSCF). The P-CSCF addressmay be discovered in one of three different ways: It may be stored in the IP Multimedia Services Identity Module (ISIM). The UE may request it…

    August 10, 2021
  • 5. IMS Procedure: SIP Registration

    After Authentication, Security and UE Capability requests, the network accepts the Attach request and activates the EPS bearer context. Once that has happened and the UE has also established a PDP context, a typical IMS SIP client registration (Figure 4) begins: The IMS client attempts to register by sending a REGISTER request to the P-CSCF.…

    August 10, 2021
  • 6. IMS Procedure: Event Subscription

    Suppose the UE now intends to monitor a specific “registration event”. In this context an event may be a callback (to provide audio for a shared web event, for example) or an update to a “buddy list” or a message waitingindicator. In general, this means that the UE is asking to be notified any time…

    August 10, 2021
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Dr Moazzam Tiwana

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