GPRS Attach

→ Before a mobile station can use GPRS services, it must register with an SGSN of the GPRS network. The network checks if the user is authorized, copies the user profile from the HLR to the SGSN, and assigns a packet temporary mobile subscriber identity (P-TMSI) to user

PDP Context

→ After the attachment to any SGSN, one of the GGSN is requested to create a data connection to the mobile station (MS) which is named PDP (Packet Data Protocol) context activation

PDP Address

→ Unique IP address provided to MS during PDP context activation from GGSN

APN (Access Point Name)

→ APN is defined for specific services offered by operator. It is used to resolve GGSN private IP address in a PLMN

RAI (Routing Area Identity)

→ RAI is broadcast as system information. MS uses this information to detect a change of RA at cell reselection. In absence of Gs interface, Routing Area is same as Location area in GSM

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