IMS Network Element - RACS+NASS (TISPAN)

IMS Network Element - RACS+NASS (TISPAN) (Study Note)

NASS = Network Attachment Subsystem
CLF = Connectivity session Location and repository Function
NACF = Network Access Configuration Function
UAAF = User Access Authorization Function
PDBF = Profile Data Base Function
CNGCF = CNG Configuration Function

RACS = Resource Admission Control Subsystem
A-RACF= Access-Resource and Admission Control Function
SPDF = Service-based Policy Decision Function

AF = Application Function
CNG = Customer Network Gateway
ARF = Access Relay Function
AMF = Access Management Function
RCEF = Resource Control Emulation Function
BGF = Border Gateway Function
BTF = Basic Transport Functions

NASS Function OV:
- CLF holds a number of records representing active sessions. These records contain information received from the NACF and the UAAF/PDBF, and additional statically configured data. CLF registers the association between network location information received from the NACF and geographical location information.
- NACF is the extension of existing DHCP component and is responsible for the IP address allocation to the UE.
- PDBF contains NASS User authentication data and the NASS User network profile related to the required network access configuration as a Policy Server which is responsible for mapping the subscriber’s services
- UAAF is the extension of existing Radius Server component and performs NASS User authentication, as well as authorization checking, and retrieves authentication data and access authorization information from the NASS User network profile information contained in the PDBF.
- CNGCF is used during initialization and update of the CNG

RACS Function OV:
- A-RACF performs admission control, Subscriber access profile-based checking and Resource admission control depending on the operator's policy, for the access and aggregation segment.
- SPDF acts as a final Policy Decision Point for Service-Based Policy control (SBP) and makes policy decisions by using service policy rules defined by the network operator, and hides the underlying network topology from applications and from interconnected SPDFs.

Further Information: https://docs.google.com/fileview?id=F.6000c46a-184d-406c-a1d0-1ffa4bf8d82b&hl=en

IMS Network Element - AGCF Overview (TISPAN IMS-Based PES)

IMS Network Element - AGCF Overview (TISPAN IMS-Based PES) (Study Note)

Discussion: CS-Based PES, IMS-Based PES and IMS PSS

AGCF Function OV:
- AGCF appears as a P-CSCF to the other CSCFs
- Act as an MGC for controlling media gateways functions
- The first point of contact for residential and access media gateways
- Perform signalling interworking between SIP and analog signalling via the P1 reference point.
- Act as a SIP User Agent
- Delivering the appropriate dialtone pattern;
- Processing mid-call events

AGCF to interact with the resource control subsystem (SPDF in RACS) for the following purposes:
- authorization of QoS resources;
- resource reservation;
- gate control (including NAPT binding information relay)

e2 supports information transfer between the P-CSCF or the AGCF and the CLF of Network Attachment Subsystem.
- AGCF may require to control residential or access media gateways
- Receipt of an off-hook or flash-hook event from MG, AGCF shall autonomously request the MG to play a dial tone, or aware of dial tone changes in case some specific supplementary services are activated, or Special dial tone if using service code
- etc.

Further Information: https://docs.google.com/fileview?id=F.c094cbfe-f59d-4d0c-87eb-2fe62d24f562