For the purposes of the present document, the terms and definitions given in TR 21.905
and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905
Domain Name System as defined in RFC 1034
, RFC 1035
, and as used in 3GPP in TS 23.003
and GSMA PRD IR.67 
The phrase "operators shall provision" in this document is intended to convey what is required to provision in DNS to provide DNS based selection for the corresponding function documented here. If there is a non-DNS procedure in an operator's network for that function then there is no functional requirement for the operator to provision such DNS records.
The term "S4-SGSN" refers to a Release-8 SGSN that has at least one set of S4/S3/S16 interfaces enabled.
The term "Release 8 SGSN supporting only Gn/Gp" refers to a Release 8 or later SGSN that either explicitly does not support S4 interfaces or all S4/S3/S16 interfaces are disabled due to operator policy. Such a node cannot use an SGW but can use a collocated PGW/GGSN. See TS 23.401 Annex D
for use cases.
The term "Release-8 SGSN" applies to either case.
For the purposes of the present document, the abbreviations given in TR 21.905
and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905
Dedicated Core Network
Dynamic Delegation Discovery Service
Domain Name System
E-UTRAN Cell Global Identification
evolved High Rate Packet Data
Fully Qualified Domain Name
Globally Unique Temporary Identity
eHRPD Serving Gateway
Local IP Access
Routing Area Identity
Selected IP Traffic Offload
Tracking Area Identity
Tracking Area Update
Trusted WLAN Access Network