Letters

New Presence Technologies and Services
for the Broadband-network Age
Shigefusa Suzuki, Yoshitsugu Kondo, Michio Shimomura†,
and Kenichi Ooto
Abstract
The concept of “presence” is attracting attention as the basis for new telecommunications services forbroadband networks. This article describes presence-control techniques that can be adapted to various
services as differentiated functions and new presence applications developed in NTT Information Sharing Platform Laboratories.

1. Trends in presence services and the state ofstandardization

services since last year and will continually expand
the variety of these services in the near future.

1.1 Presence services
The popularization of broadband networks has
been accompanied by the advent of various new
telecommunications services, which deal with thestatus of a person or thing, which is known as its“presence”. The best-known example is instant messaging (IM), where users wanting to exchange messages can confirm presence information to determine
whether someone is online. Content-delivery services
that deliver information that is relevant and timely interms of the user’s location and preferences havestarted and they are expected to become enormously
popular. A more specific area is remote nursing-careservices where a monitor watches health-related presence information, such as data about the physicalcondition of an elderly person living alone. Sensing
devices such as radio-frequency identification(RFID) tags and readers are applied in ubiquitous
sensing services for getting presence data that showswhether items are in or out of stock. IM services havevery quickly become popular, and many companies,
led by AOL and now including Yahoo!, Microsoft,and many others, are already providing IM services.
NTT-group companies have been providing presence

1.2 Standard presence technologies
Presence services are typically based on SIP (Session Initiation Protocol) and PAM (Presence andAvailability Management).
(1) SIPSIP (RFC3261) is a control protocol for creating
and managing a multimedia session on IP networks. This protocol has been standardized by theSIP WG (Working Group) [1] of the IETF (InternetEngineering Task Force). In SIP, information fortransfer is specified in a plain-text format like
HTTP (Hyper Text Transfer Protocol). SIP is now
very well known among people in the telecommunications field and is being applied in VoIP (voiceover IP) services. The protocol for exchanging
presence is prescribed by the RFC3265 standard,developed by the SIP WG. An important extension
to SIP called SIMPLE (SIP for Instant Messaging
and Presence Leveraging Extensions) has been provisionally defined in an Internet Draft (pre-standardization document) developed by the WG of thesame name [2]. The SIP protocol has already been
applied in Windows Messenger, the IM service
from Microsoft. The protocols are genericallyreferred to as SIP/SIMPLE. A basic sequence in theexchange of presence information using SIP/SIMPLE is shown in Fig. 1.

† NTT Information Sharing Platform Laboratories
Musashino-shi, 180-8585 Japan
E-mail: shimomura.michio@lab.ntt.co.jp

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Letters① Subscribe(subscribe topresence service)② Notify(report on user’s presence)③ Register or publish(change of presence)

Watcher④ NotifyPresence(report change in presence) server

Presentity

Fig. 1. Basic sequence in the exchange of presence data.

(2) PAMThe PAM [3] standard specifies various basicpresence application programming interfaces(APIs) and was prepared by the PAM Forum, Parlay Group [4], ETSI (European Telecommunication
Standards Institute), 3GPP (3rd Generation PartnerProject), and other groups. The APIs cover themanagement of presence information and communication methods for both people and things. TheseAPIs give service providers an efficient way todevelop highly portable service applications.
2. Presence platform and architecture
2.1 Architecture
At NTT Information Sharing Platform Laboratories, we are applying SIP/SIMPLE and PAM as thebases of the new common presence architecture
shown in Fig. 2. This architecture is intended to provide a comprehensive presence service. A service
provider places the presence system in a physicalstructure that suits the scale of the service, i.e.,
according to whether it is for the mass market, specific corporate users, or mobile-terminal market, etc.
The presence system we have developed supports
APL

two forms of presence-information management. In
one, the management function is centralized on thenetwork system. In the other, the management function is decentralized and handled by both the network
system and user terminals. We have adopted opensource software to cut down on middleware license
fees. As well as reducing the development cost, opensource software lowers maintenance costs and shortens the period of development.
2.2 Presence platform
A presence platform is composed of the basic presence module and the presence-control module.
The basic presence module is based on standard
presence technology. Its functions consist of presence-management functions based on PAM, presence-signaling functions based on SIP/SIMPLE, anda mediation function which maps the SIP/SIMPLE
messages to PAM APIs.
The presence-control module provides common
functions that are independent of specific presenceservices but are not prescribed by the standard presence technologies. Most conventional presence products were designed for IM, and their application toother presence services was not considered. The conAPL

PAM+other APIs
HTTP/SOAP etc.

HTTP/SOAP etc.
Presence platform

APL

APL

APL

APL

Presence control
PAM+other APIs

APIs
SIP/SIMPLE

User presence
functions
Presentity

PAM

SIP/SIMPLE

Basic presence
functions

Watcher presence
functions

Presence server

WatcherFig. 2. Common presence architecture.

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trol module needs new presence functions if it is to be
applicable to the various presence services expectedin the future. We have thus been developing manysuch functions over the last year and have incorporated them in this module.
3. New presence-control functionsFigure 3 outlines the presence-control functions
that we have developed and incorporated in the presence-control module. These functions can be adaptedfor various services as differentiated functions. We
explain each of these functions below in sections 3.1
to 3.5.
3.1 Distributed presence management
In most conventional services using presence information such as Windows Messenger, all of the presence information is stored on the network side. However, when the presence information of a service
includes private information (state of health, likes anddislikes, interests, contents of the refrigerator, etc.),users might be reluctant to accept entrusting theI don’t want tostore private presence Developing a presence
I want toknow about changes information on theapplication program
network.
in the presence
takes a lot of time
information.
and money.
I want tosee a greater
variety of presence
information.

information to the network side. We have solved thisproblem with a distributed-management function, in
which presence information is stored on either theuser or network side as determined by the presentity(presence entity). Private presence information will
normally be managed on the user side and only beopened by an authorized party or organization, andthen only when this is necessary. Another approachthat might suit some applications will be to have theprivate information gradually opened to others as
they satisfy certain conditions or respond to certain
incentives.
3.2 Presence accumulation and reference
In a conventional presence service, only the present
state is managed as presence information. The presence accumulation and reference function accumulates presence information over time; we can thenlook at its transitions over time. The value of thisfunction is that it enables various secondary uses ofpresence information, such as the automatic generation of a diary or album for personal use and the generation of statistical data for market research.
Where are you?

Attribute added
to the presence
information

Having to update
notify (Action, Location) Action: working
WatcherPresentity
Location: Shibuya
my presence information
Presence notification is now usuallyat the same time every
Presentity decides whether thepresentity controlled; the new function
day is irritating.
new presence attribute is open
lets the watcher request access theto the requesting user or not.
presence information of the presentity.

Control of watcher-initiated access

Problems and inconvenience of conventional services
Presence info. that requires
privacy is kept on the user side.

PDA
Presence
information

Presence server

Presence
information

Presence information

Presentity

PC
Presence
information

Presence info. that carries no privacy
requirement is kept on the network side.

Distributed presence-management function
Statistical processing of Conventional presence services only
Presentity
cover the current presence state;accumulated(watching athis function accumulates presence
presence
information as it changes over time. video program)
information• Degree of α wave
generation…

Presence accumulation/reference function

Presentity(operators at the call center)

Operator 1

Operator 2Updating of presence information is

Watcher automatic and follows a predefined
Operator 3(customer) schedule.
Automatic updating of presence information
Module for defining andediting the specification

Visual designof the service
specification

Specification-to-code converter

Compensatory data Data on conversion
saveCompensation Conversion C, Java etc.
Internal format
Source codeck

Secondary use ofpresence information in,e.g., market research• Program title

Presence • Timeserver • Attributes (sex, age, …)

Operator 1: closed
Operator 2: closed
Operator 3: closed

5:00 pm
Presence
serverche

Accumulatedpresence
information

Operator 1: busy
Operator 2: openOperator 3: resting

checkWatcher

Presence information
Presence server Action: working

notify (Action)
request (Location)

Cooperation withother functions

Conversion into
source code

Service specification
checkerChecking for errors in theservice specification, e.g.
Inter-function cooperation module in message sequences

Presence-application development tools

Fig. 3. Functional blocks of the presence service.

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3.3 Control of watcher-initiated accessConventionally, access to presence information andpermission for its notification, in terms of bothallowed viewers and allowed information, are generally controlled by the presentity. This function gives
us a framework in which a watcher can request accessto the presence information of a presentity. We canthus achieve new types of flexible presence service
where access to presence information is cooperatively controlled by the presentity and watcher.
3.4 Automatic updating of presence information
All sorts of presence information will be handled in
the near future. Relying on manual input of presence
information, as is currently the case, is very inefficient. One solution to this problem is the use of sensors as automatic means of inputting presence information. On the other hand, timer-driven control iseffective in cases where the change in presence stateis based on a regular activity. Presence information
can also change according to certain other fixed rules,
such as the sharing of an address by family members.
This function thus covers both the scheduled updating of presence information and fixed rules of thetype described above.
3.5 Presence-application development tools
No development tools that support the PAM API
are available for generating presence application, so
developing applications requires much time and cost.
We have developed an application generator whichruns on the presence server. Its main functions are a
GUI (Graphical User Interface)-equipped function
for defining and editing the service specification, afunction that converts the service specification thus
defined into source-program code and compensatesfor deficiencies in the input specification, a function
for verifying the input service specification by checking for errors in input, and a function that retains theindependence of the above-mentioned functions
while getting them to cooperate. These functions
form an environment for low cost and quick development of high-quality presence applications.
4. New presence applications
We think that the desires to acquire a feeling of connection with other people and to receive personalized
services are the main driving forces for the exchangeof presence information between parties on a network. In this section, we describe the Presence Cluband Splittable Communicator [5] as examples of82

applications being developed at NTT Information
Sharing Platform Laboratories.
4.1 Presence Club
The Presence Club is an application for collaborative communication based on augmented collectionsof digital photographs and so on. It operates withelectronic albums of photographs or other objects
connected with the user’s (presence club member’s)
past presence state. It draws on current presence
information about other people or things seen in theobjects to provide a smooth path into future communications by VoIP, video phone, a chat session, etc.
Including presence information in this way creates amuch stronger feeling of connection than the photograph and memory alone. In the prototype system,
text and photographs provide the current presence
information. A camera-equipped cellular phone thus
constitutes a very convenient input terminal. Ourintention is to give the Presence Club the capability tooperate with various media, including video, voicerecordings, electronic documents, and other information. The operation of the Presence Club is shown inFig. 4.
4.2 Splittable Communicator
The Splittable Communicator application gives
users continued access to telecommunications services such as videophones as they move from network to network (for example, from a PHS cell to thehotspot of a wireless LAN), or change terminals (forexample, from a PC to a PDA). Using these kinds ofpresence information, Splittable Communicator does
this by switching the telecommunications sessions
between networks and terminals. The system’s architecture is shown in Fig. 5.
In this application, the presence system manages
presence information such as whether the user isonline or offline, the user’s location, the applications
available to terminals and their parameters. Splittable
Communicator is intended to select the most appropriate terminal for the user (for example, the terminal
closest to the user as he or she moves about), andautomatically switch the telecommunications session
to more appropriate terminals as they become available.
5. Conclusion
At NTT Information Sharing Platform Laboratories, we are developing presence-control technologies for various services as differentiated functions.
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Presence server
Gateway server
Presence data:
photographs of group
IP network
members accompanied
Presenceby text
Presence
Selecting any photograph brings
Cellular phone network
up current presence informationon the objects in the photograph.
Camera-equippedPC
PDA
cellular phone
Group list
Details of friends
Nancy
Traveling inMiyazaki.
Lots of fun!
MasamiDrinking in
Roppongi.
Happy!
Akiko
Free now.
Waiting for
you to call!

(a) Photographs of groups(past presence information)(b) Presence (photographs and text)

Fig. 4. Presence club service.
Notification ofPresence server presence (trigger for Carry-on serverswitching sessions)
Terminal information
Session controlmanagement

Reference list ofterminals (for appropriatechoice of terminals)

Called party

Transfer of telecommunications session

PDA

PDA

Desktop PC

Fig. 5. Concept of Splittable Communicator.

The Presence Club and Splittable Communicator are
examples of new presence applications. By developing these presence technologies and applications, we
expect to make more convenient and personalized
services in various business fields.

References
[1]
[2]
[3]
[4]
[5]

Vol. 1 No. 5 Aug. 2003

http://www.ietf.org/html.charters/sip-charter.html.
http://www.ietf.org/html.charters/simple-charter.html.
ETSI, “Open Service Access; Application Programming Interface;Part 14: Presence and Availability Management SCF,” Jul. 2002.
http://www.parlay.org/.
T. Nakanishi, T. Shibata, Y. Orime, and S. Suzuki, “Proposal of service mobility technology in ubiquitous network,” NTT R&D, Vol. 52,No. 3, pp. 223-230, 2003 (in Japanese).

83Letters

Shigefusa Suzuki
Executive Manager, Communication Platform
SE Project, NTT Information Sharing Platform
Laboratories.
He received the B.S., M.S., and Ph.D. degrees
in electrical engineering from the University ofElectro-communications, Chofu, Tokyo in 1978,1980, and 2000, respectively. In 1980 he joined
the Musashino ECL, NTT, Japan. Until 2002, hewas engaged in research and development of onboard baseband switches for satellite switched
TDMA communication systems, digital mobile
communication systems, the Personal Handyphone System, and the Advanced Intelligent Networks system. He is a member of IEEE Communication Society and the Institute of Electronics, Information and Communication Engineers(IEICE) of Japan.

Yoshitsugu Kondo
Senior Research Engineer, Supervisor, GroupLeader, Ubiquitous Computing Project, NTT
Information Sharing Platform Laboratories.
He received the B.S. and Ph.D. degrees in
information engineering from Yamanashi University, Kofu, Yamanashi in 1983 and 1996,
respectively. In 1983, he joined the ElectricalCommunication Laboratories, Nippon Telegraphand Telephone Public Corporation (now NTT),
Tokyo, Japan. In 1994, he joined NTT Network
Service Systems Laboratories. In 1999, hemoved to the NTT Information Sharing Platform
Laboratories. He is a member of IEEE, IEICE,
and the Information Processing Society of Japan.

84

Michio Shimomura
Senior Research Engineer, Communication
Platform SE Project, NTT Information Sharing
Platform Laboratories.
He received the B.S., M.S., and Ph.D. degrees
in electronics and communication engineeringfrom Waseda University, Tokyo in 1988, 1990,and 1993, respectively. In 1993, he joined theNTT Switching Systems Laboratories, Tokyo,
Japan. In 1999, he joined NTT EAST Researchand Development Center. In 2002, he moved toNTT Information Sharing Platform Laboratories.
He was engaged in research and development on
the Advanced Intelligent Networks system until
2002 and since then on presence service systems.
He is a member of IEICE.

Kenichi Ooto
Senior Research Engineer, Ubiquitous Computing Project, NTT Information Sharing Platform Laboratories.
He received the B.S. and M.S. degrees inindustrial and management systems engineeringfrom Waseda University, Tokyo in 1990 and1992, respectively. In 1992, he joined the NTT
Switching Systems Laboratories, Tokyo, Japan.
He was engaged in research and development on
the Advanced Intelligent Networks system until
2001 and since then on presence service systems.
He is a member of IEICE.

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