To present general and detailed information about mobile wireless networks such as GSM, GPRS, UMTS, LTE, WIMAX and 5G.
To present network architecture, protocols stack, radio access technology, signalling procedures.
Questions and Answers concerning particular and often very detailed issues given without introduction.
Comments, questions are of course welcome!!!
Q: Why AAL2 on Iu interface needs ALCAP and AAL5 does not need this signaling protocol ? A: AAL5 is using PVC configured by O&M, hence there is no need to establish, release or maintain this connections. AAL2 is not using PVC but VC/VP which need to be established, released and maintained by separate signaling protocol i.e. ALCAP. Q: What is the meaning of PDU and SDU and what is the difference between them ? A: PDU is Protocol Data Unit and SDU is Service Data Unit. Difference between them and their role should describe following figure
Q: What means NNI and UNI ? This two terms can be seen together with SAAL layer. A: NNI means Network-to-Network Interface also known as Network-Node Interface. UNI means User-to-Network Interface.
This post is to give short description of NAS protocols, procedures and functions.
NAS is a layer for communication between Ue and Core Network (CN). This communication is transparent for underlaying Access Stratum.
GMM - GPRS Mobility Management
MM - Mobility Management
SM - Session Management
CC - Call Control
SS - Supplementary Services
SMS - Short Message Services
SM, SMS, SS and CC form a group of protocols called Connection Management.
Figure - Inter protocols communication MS side [3GPP 24.007]
SM - its functions is to activate, deactivate or modify PDP contexts which are sessions for PS traffic in UMTS/GPRS networks