telecom • networking • design

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S1AP View of LTE Attach and EPS Bearer Setup

This sequence diagram looks at LTE Attach and EPS Bearer Setup from the S1AP vantage point. The following signaling is covered:

  1. UE Attach, authentication and security signaling
  2. Setup of two EPS Bearers (RAB id 5 and 6)
  3. Release of UE context due to inactivity
  4. Reestablishment of the UE context with a Service Request.

You can click on individual messages in the sequence diagram to see field level details.

Click to see the "S1AP View of LTE Attach & EPS Bearer Setup"  sequence diagram


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LTE security: encryption and integrity protection call flow

LTE key hierarchy

LTE security is based on a shared secret key K between the USIM and the HSS. The UE, the eNodeB and the MME derive keys for encryption and integrity protection from K.

The derived keys are used for:

  • NAS encryption and integrity protection
  • RRC encryption and integrity protection
  • User plane encryption

The key derivation and the key exchange call flow is described in the following link:

LTE security procedure: authentication, encryption and integrity protection


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TCP/IP Tutorial and Technical Overview IBM Redbook

Free TCP/IP book from IBM:

Part 1. Core TCP/IP protocols
Chapter 1. Architecture, history, standards, and trends
Chapter 2. Network interfaces
Chapter 3. Internetworking protocols
Chapter 4. Transport layer protocols
Chapter 5. Routing protocols
Chapter 6. IP multicast
Chapter 7. Mobile IP
Chapter 8. Quality of service
Chapter 9. IP version 6
Chapter 10. Wireless IP

Part 2. TCP/IP application protocols
Chapter 11. Application structure and programming interfaces
Chapter 12. Directory and naming protocols
Chapter 13. Remote execution and distributed computing
Chapter 14. File-related protocols
Chapter 15. Mail applications
Chapter 16. The Web
Chapter 17. Network management
Chapter 18. Wireless Application Protocol
Chapter 19. Presence over IP

Part 3. Advanced concepts and new technologies
Chapter 20. Voice over Internet Protocol
Chapter 21. Internet Protocol Television
Chapter 22. TCP/IP security
Chapter 23. Port based network access control
Chapter 24. Availability, scalability, and load balancing
Appendix A. Multiprotocol Label Switching

IBM TCP/IP Redbook