Service mobility and recovery in communication networks

DETAILED DESCRIPTION The example embodiments are applicable for use with all types of cellular networks and local radio networks, including wireless local area networks (WLAN), and interconnected systems using SIP for voice, message, data and image transfers between systems in such networks.
For example, 3rd generation GSM networks include data networks using General Packet Radio Service (GPRS) technology for mobile data networking services and personal multimedia services, and Enhanced Data Rates for Global Evolution (EDGE) technology for high bit rate data services.
GPRS technology is used in GSM networks to enable users to connect at higher data rates and facilitate applications such as wireless email and web-browsing.
EDGE boosts data speeds and allows video and mobile multimedia applications with data rates as high as 473 kbps.
BlueTooth networks and/or Wideband CDMA (WCDMA) networks may be used in place of the wireless local area networks (WLAN).
However, for the sake of simplicity, discussions will concentrate mainly on mobility and service recovery in a 3G cellular network such as that described in 3GPP TS 23.
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The example embodiments use a new, specially designated subscribe message in the SIP event notification scheme to have information made available to a user's terminal.
However, the principles and features of the example embodiments are not restricted in their application to SIP, and can be applied to any messaging protocol providing for subscription messages and notification messages.
Attention now is directed to the drawings and particularly to FIG.
2, which shows the flow diagram for a mobility and service recovery method according to the example embodiments, keeping in mind that the example embodiments may be carried out in a variety of different networks.
In general, a user terminal must provide some identification to a network in order to gain access and receive communication services.
The identification may be anything that uniquely identifies the user, such as a SIM card or telephone number