For the purposes of the present document, the [following] terms and definitions [given in ... and the following] apply.
For the purposes of the present document, the following abbreviations apply:
AMR
Adaptive Multi-Rate
AS
Application Server
CN
Core Network
CSCF
Call Session Control Function
DSL
Digital Subscriber Line
FQDN
Fully Qualified Domain Name
HSS
Home Subscriber Server
HTTP
Hyper Text Transfer Protocol
I-CSCF
Interrogating CSCF
IM
IP Multimedia
IMS
IP Multimedia CN subsystem
IP
Internet Protocol
IP-CAN
IP-Connectivity Access Network
MGCF
Media Gateway Control Function
MRFC
Multimedia Resource Function Controller
MRFP
Multimedia Resource Function Processor
NGN
Next Generation Network
PCRF
Policy and Charging Rules Function
P-CSCF
Proxy CSCF
PSI
Public Service Identity
S-CSCF
Serving CSCF
SDP
Session Description Protocol
SIP
Session Initiation Protocol
UE
User Equipment