Dr. Deepak Tyagi,
3G Mobile Network Architecture & Security Features
The aim of the research was to study the 3G (third generation) wireless networks architecture and its security features. From the data gathered through observations and literature review, security feature that are available in 3G networks were identified and methods that may be used to maximize the security in networks were determined. Recommendations are given to improve the security 3G networks.
3G or 3rd generation is technology for mobile network is based on the IMT-2000 standards according to specification by International Telecommunication Union(ITU). It helps users in getting greater network capacity Through improved spectrum efficiency like video calls, broadband wireless data, music downloads, receiving streaming video from the Web, sending and receiving faxes, instantly downloading e-mail messages with attachments etc. 3G networks have potential transfer speeds of up to 3 Mbps (it takes around 15 seconds to download a 3-minute MP3 song). And if we compare the fastest 2G phone which can achieve up to 144Kbps(i.e. It takes around 8 minutes to download a 3-minute song) 3G speed much faster than it. They are intended to provide a global mobility. In 1998 Third Generation Partnership Project (3GPP) was formed for the technical specification work.
3. UMTS network elements and interfaces
The core network is divided logically into two domains circuit-switched (CS) and packet-switched (PS). The CS domains work is to handle circuit-switched connections, and the PS domains work is to handle the packet transfer. The core network of CS is built around Mobile Switching Centers (MSC) and the core network of PS around Serving GPRS Support Nodes (SGSN). The various registers of core network are common in both the domains. But Visitor Location Register (VLR) is typically employed by CS domain only. Note that not all the interfaces shown and named in figure A above and also the list of network elements in not comprehensive.
Figure A- UMTS network elements and interfaces
3.1 Core Network
3.1.1 The mobile switching center (MSC) is the center element of circuit-switched core network. We can use same MSC to serve both the GSM-BSS and the UTRAN connections. In addition to the RANs (Radio Access Network), it has to interfaces to fixed PSTN network, ISDN, other MSCs, the packet-switched network i.e. SGSN, and various registers of core network (HLR, EIR, AuC). Generally, the VLR is part of MSC and the interface between them exists only logically.
3.1.2 Visitor Location Register (VLR) – The visitor location register keeps the information about visitor in an area under particular MSC. One VLR can handles the visitor register of several MSC. It contain information of all the active subscribers in its area. It keep the record of all those subscribers also whose network is their home network. Thus the visitor location register name is little misleading as most of the user entries are from home network only. It has similar information as that of the home location register (HLR). But VLR keeps information which are keep on changing or temporarily in nature, whereas HCR is a permanent information storage. When a user make his subscription, his data in entered into his home HLR. Same is copied into VLR of that location. When user moves from location A to location B. The information regarding that user is copied from location A VLR to location B VLR. See figure B below:
Figure B: VLR entries changes as user move to another VLR
3.1.3 Home Location Register (HLR)- The home location register contain the permanent information of subscriber. Information of each subscriber is stored in only one HLR. The HLR can me implemented in two ways: In as single unit with MSC/VLR or as separate unit with MSC/VLR as one unit and HLR/AuC/EIR as combined another unit as given...