[Intro. to Computer Security Course Note] Ch 24 (supplement 2)

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Ch24 Supplement. Cellular Network Security

Evolution of mobile networks

Standards Body for Mobile Network: 3GPP

  • An international standards body
  • Evolves and standardizes GSM, UMTS, LTE, among others
  • We will primarily discuss 3GPP standards

Current Mobile Networks

Technology: 3G -> 4G

  • 4G LTE: First global standard for mobile broadband
    • More data capacity
    • Faster speed
    • Lower latency
    • New service paradigm
  • Key enabler: network architecture evolution

Network Architecture Evolution

2G is based on Circuit Switching (CS)

  • End-end resources reserved for “call”sss
    • No sharing

CS Signaling

  • Used to setup, maintain, and tear down VC
  • Used in 2G, 3G

Packet Switching (PS)

  • Store-and-forward at intermediate routers
  • Used by the Internet

PS Signaling

  • No call setup at network layer
  • No network-level concept of “connection”
  • Packets forwarded using destination host address
    • Packets between same source-destination pair may take different paths

4G Cellular Network Architecture

- MME: Mobility Management Entity - BS: Base Station

3G/4G Network Architecture

Operations

  • Two main planes in operation in parallel
    • Data/User plane: content delivery
    • Control plane: signaling functions
      • Three Major Functions
        • Radio Resource Control (RRC)
        • Mobility Management (MM)
        • Connection Management (CM)
  • Additional plane that woks with the above
    • Management plane: configurations, monitoring

How to set up data services in 4G networks

Security in 4G networks

- IMSI (International Mobile Subscriber Identity): 國際移動用戶識別碼 - TMSI (Temporary Mobile Subscriber Identity): 臨時移動用戶識別碼 -