IlJin Lee

Basic call flow for interoperability test in the presence services based on SIP

Presence service is emerged to meet the needs of integrated service and presence service will be a core function within integrated service. IETF SIMPLE WG generates standard SIP extensions for presence service. In this paper, we described the presence service systems including internal logical function modules. We classified functions of presence service systems with itemized functions, conditions to be occurred related SIP request messages and response message for each request message. And, we also described the basic call flows for interoperability test among presence service systems based on SIP

Design considerations for user authorization in the presence services based on SIP

SIP plays an important role in VoIP service infrastructure. Presence service is emerged to meet the needs of integrated service and presence service is a core function within integrated service. IETF SIMPLE WG generates standard SIP extensions for presence service. In this paper, we described the service scenarios of presence services based on SIMPLE. We also described the construction of presence system. Especially, we described the design considerations of presence agent supporting for multiple presence packages and those of presence agent supporting for user authorization function

A Study on Keepalive Mechanism between SIP UA and Proxy server for Internet Telephony Service

When Internet telephony service is provided using SIP protocol, The session initiation protocol (SIP) does not define a keepalive mechanism for the sessions it establishes. Although the user agents may be able to determine whether the session has timed out by using session specific mechanisms, proxies will not be able to do so. The result is that call stateful proxies will not always be able to determine whether a session is still active.

A study on design and implement of XCAP server

A XCAP (XML configuration access protocol) proposed by IETF SIMPLE WG is based on both XML and HTTP protocol. XCAP server maintains users configuration information of specific application described by XML. This protocol can be applied to many application servers for adapting users preferences. There are many way to interwork with other applications. In this paper, we will describe the experience of designing and implement of XCAP server and the way of interworking with application servers

Study on Emergency Services for VoIP Based on IP Network vs. Domestic Emergency Network

Enhanced 9-1-1 (E9-1-1) Service is a public safety feature that allows customers to report an emergency or request emergency assistance by dialing the 3-digit telephone number “9-1-1.” Emergency calls originated in this manner are then routed to the appropriate Public Safety Answering Point (PSAP) based on the location from which the call was originated. In this paper, we are intended to analyze the structure of system to efficiently provide emergency service using SIP protocol-based internet telephone under IP network environment, and the assessment of its performance.

Design for supporting the multimedia emergency VoIP using PSTN and IP network

Internet is rapidly increased, and various services are deployed over internet. It is an important issue to support emergency service in VoIP, because many users want to use the emergency service similar to the service in PSTN network. VoIP terminals which can create audio, video, and image data are able to send multimedia data to emergency agent. But the current VoIP service cannot provide multimedia data to emergency agent, because emergency calls have to flow through PSTN network. If emergency agent has got some video as well as audio data for emergency call, it will be very helpful to rescue somebody in danger. In this paper, we will consider new network model to provide multimedia data to PSAP in emergency call.

A Study on methods of MCID(Multimedia Caller IDentification) supplementary service based on SIP

MCID(Multimedia Caller identification) service allows the user to allocate and send distinctive caller information to a called party. When the user (calling party) makes a communication, the pre-selected contents (e.g. video business card) are played to user equipment of the called party, until the called party answers. The media types of contents presented to the called party may be audio, video, image or text.

A study on user data management for SIP-based IMPP services

XCAP (XML configuration access protocol) is protocol for communication between XCAP client and XCAP server. XCAP allows a client to read, write and modify application configuration data, stored in XML format on a server. XCAP maps XML document sub-trees and element attributes to HTTP URIs, so that these components can be directly accessed by HTTP. In this paper, we study on XCAP server behaviors SIP-based IMPP services in order to buddy list control

Design and Implementation of CPL Client for VoIP

VoIP that conveys voice in internet is getting into the spotlight as means to alternate existing PSTN in corporation as well as users. Current VoIP is furnishing voice efficiently, but it needs to support various services for VoIP acceleration. IETF is developing CPL standard which is call processing language for supporting various services. User has to store script to specific server for the use of CPL, therefore it is required client to support CPL. This paper describes about design and implementation of SP-based CPL client for various services. The CPL client was implemented using LINUX 2.4.x, C, and GTK1.2