Continuous Media Support for KMSF-CODE Architecture - CiteSeerX

Continuous Media Support for KMSF-CODE Architecture 1

Tadashi Okoshi

1

1

1

Hideyuki Tokuda

Department of Policy Management, Keio University

Graduate School of Media and Governance, Keio University

Introduction

Keio Media Space Family Project(KMSF) Project [2] researches on the application environment which supporting the intelligent collaborative working among the group of members, using the technology of the distributed real-time microkernel(Real-TimeMach) [1], the realtime network protocol server, integrated media server and continuous media base. In this paper, we describe continuous media support for the KMSF-CODE Architecture, which stands for \Keio Media Space Family - Collaborative Object for the Distributed Environment". KMSF-CODE is one of the KMSF Environment, with its dynamic QOS control. There are two features in KMSF, (1)the share of the QOS control policy by the \QOS Policy Object" among the users, and (2)the QOS control based on both the QOS Policy of the user who sends the continuous media and the QOS Policy of the user who receives the continuous media. 2

3

Masahiro Mochizuki

Department of Environmental Information, Keio University

2

3

2

Hitoshi Nakazawa

KMSF-CODE Architecture

KMSF-CODE Architecture[3, 4] is an architecture implemented based on the CODE model, and supports intelligent collaborative activity among the group of members. Figure 1 whos the KMSF concept. KMSF-CODE architecture consists of both Keio Media Space Board(KMSB) as the CODE Server and Keio Media Space Navigator(KMSN) as the CODE client. KMSB stores and manages the CODE-objects, and serves objects to KMSN. KMSN ,which is running on the users PDAs or mobile PCs, is the browser software which enable users to construct and/or edit the CODE-objects and browse the objects on KMSB. The operation of the posting an object up to the KMSB is called \post-it", and the operation of the viewing the objects on the KMSB is called \fetch-it." Keio Media Space Board

Workstations / PCs

WAN / LAN / WaveLAN

post-it fetch-it

Personal Digital Assistants

Mobile hosts

Figure 1: KMSF Concept

3

Continuous Media in CODE Model

In the CODE model, users can manipulate the continuous media information, such as the movies and audios, as the \Media Collaborative Object"(Media-CO) integratedly , as same as the non-continuous media information. The \post-it" and the \fetch-it" operation of the continuous media continues for the period, so they are called \continuous post-it" and \continous fetch-it." 3.1

QOS Control Requirement

3.2

QOS Policy Object

3.3

Continuous Media Operation With QOS Control

QOS Control is required during the \continuous postit" and \continous fetch-it" operation in the CODE model to control the quality of continuous media objects and serve them to the users at a requested quality, responding the amount of the available resources in the restraint environment of the computing resources and the network resources. Furthrmore, there are two interactions on the CODE model, 1-to-1 interaction and 1-to-n interaction. In such an environment, against the one continuous media object, several posting users' QOS control policies and the several fetching users' QOS control policies exist together at the same time. It is necessary that the appropriate framework of the QOS control to process them eciently. In order to process the 1-to-1 and 1-ton interaction eciently, the separation of the control policy and the control mechanism of the QOS control is done in the CODE model. We treat the QOS control policy as the \QOS Policy Object" which is a kind of Media-CO Object. In the \QOS Policy Object", there are requirement description for the continuous media QOS and relative importance level description between the QOS elements. Users can post-it and fetch-it \QOS Policy Object" itself individually. Multiple types of QOS policies can be shared to group of users. Figure 2 shows the operation example of continuous media object in the CODE model. When the posting user continuous post-its a continuous media information, user constructs two Media-COs, continuous media object and QOS Policy Object at rst. And Secondary, combining them to one Hyper-Object, user posts it to KMSB. When the browsing users ocontinuous fetch-its the continuous media object, there are two possibilities for them to ocontinuous fetch-it as followings.  continuous fetch-it with the posting user's QOS control policy  continuous fetch-it with the fetching users' QOS control policy

The former is called Original-QOS-Policy-Based (OQPB) fetch-it. The browsing users fetch-it the Hyper-

Object which is the combination of continuous media object and posting user's recommendation QOS Policy Object. The latter is called Customized-QOS-Policy-Based (CQPB) fetch-it. The browsing users fetch-it only the continuous media object as a Media-CO, and use their own QOS Policy Object or the one they individually fetch-ited from the KMSB.

QOS Controller dynamically controls quality of the continuous media data, and sends QOS-controled data to KMSN. If the browsing users changes QOS control policy, they set new QOS Policy Object to the session. KMSN postit the new QOS Pilicy Object to KMSB, and the QOS Controller in KMSB receives it. So the QOS control policy is dynamically changed. Capture Module

UDP/IP

KMSN

Continuous media Object

HO

Network Manager

QOS Policy Object A

KMSB

KMSN

post-it

Receiver Module

QOS Controler

Network Monitor

post-it TCP/IP

QoS Policy Object

KMSB

QoS Policy Object

HO

Receiver Module

KMSN

E4 QOS Group E3 QOS Group E2 QOS Group

MediaScale Module

QOS Policy Object A

KMSB Network Monitor

OQPB fetch-it B1 QOS Group

Continuous media Object

KMSB

KMSB

Continuous media Object

CQPB fetch-it

5 Dynamic QOS Control of the continuous media object in KMSF-CODE Architecture

Figure 3 shows the Dynamic QOS Control mechanism

in the KMSF-CODE Architecture. 4.1

Continuous Post-it Mechanism

4.2

IP Multicast based OQPB fetch-it

The continuous media data inputed from the KMSN capture module is sent to KMSB, using UDP/IP protocol. The Network Manager in the KMSN monitors network condition, communicating the Network Monitor module in the KMSN and the KMSB. If the network condition changes, the Network Managaer sends noti cation to the QOS Controller. The QOS Controller dynamically controls quality of continuous media data, based on QOS control policy of the QOS Policy Object. The Media Scale Module in KMSB classi es the continuous media data from KMSN into the 4 quality classes (1 basic quality level and the 3 enhanced quality levels). the Multicast Modules send each quality class data to the multicast network address, using IP multicast. When browsing user accesses KMSB to OQPB fetchit, KMSB reply IP multicast addresses to the KMSN. According to the network condition which the Netowk Monitor monitors, KMSN joins these IP multicast addresses to continuous fetch-it. 4.3

CQPB fetch-it

When browsing user accesses the KMSB to CQPB fetch-it, KMSB creates the new QOS Controller thread. KMSN posts QOS Policy Object which user want KMSB to use, and the QOS Controller receives it and accepts its QOS control policy. When the Network Manager in KMSB sends noti cation to the QOS Controller,

Network Manager Network Monitor

CQPB fetch-it TCP/IP

KMSN Network Monitor

Figure 3: Continuous Media Process Mechanism

Figure 2: QOS Policy Object and the operations 4

UDP/IP

QOS Policy Object B

KMSN

Another QoS Policy Object

Receiver Module

QOS Controler

OQPB fetch-it

Conclusion and Future Work

In the KMSF-CODE architecture, threre are the client OS and network without the resource reservation or the quality gurantee coexisted, and there are multiple QOS control policies against one continuous media object. In order to archive the dynamic QOS control in such an environment, we propose the continuous media object framework which features sharing of the QOS control policy with the \QOS Policy Object"and the QOS control based on the QOS Policy of both senders and receivers. With this architecture, we can oer the QOS control policy more exibly, and archive the higher level continuous media object suppot. The future works are the framework of the synchronization among the continuous media objects, and the negociation of the QOS control policy among the users. References

[1] H.Tokuda, T.Nakajima and P.Rao: \Real-Time Mach: Towards a Predictable Real-Time System", In Proceedings of 1st USENIX Mach Symposium, 1990", October, 1990. [2] Tokuda, Ishikawa, Mochizuki, Tomita, Kawamata: \System Architecture in Keio Media Space Family Project", IPSJ Vol.95, No.59, 95-OS-69, (1995). [3] Nakazawa, Iwamoto, Okoshi, Nagata, Mochizuki, Tokuda: \Keio Media Space Family-CODE Architecture", Proc. IPSJ Computer System Symposium, Vol.96, No.7, pp. 53{60 (1996). [4] Okoshi, Iwamoto, Nakazawa, Nagata, Mochizuki, Tokuda: \Design, Implementation and Evaluation of Keio Media Space Board for KMSF-CODE", Proc. IPSJ Computer System Symposium, Vol.96, No.7. pp. 105{110 (1996).