Computer Communications Laboratory

/ Behcet Sarikaya / Professor
/ Senro Saito / Associate Professor

The Computer Communications laboratory is involved with education and research on all aspects of computer communications. Ongoing projects in education include an SCCP project on Social Hyper-networking and two topdown courseware design projects, one on High-speed Network Courseware Design for Synthetic Worlds and another on an authoring system called AuthCAL for topdown courseware development environments.

The social hyper-networking project aims at providing communication facilities such as electronic mail, voice mail, electronic conferencing, bulletin boards, real time talk and facsimiles. The AuthCAL project has the goal of providing an object-oriented graphical user interface and programming tools to make some teaching materials. The high-speed network courseware project aims at designing graduate and undergarduate level courses to teach the basics of high-speed networking.

In research, all aspects of computer networking are being investigated. However, present interest areas are concentrated on:

• Multimedia communication systems. Multimedia synchronization, application of protocol engineering techniques for multimedia system designs, verification and testing.
• Network management protocols. Network management using internet methodology, test design and implementation of network management systems, test design for the management information bases.
• Personal Communication Systems. Mobile and wireless networks; Multimedia for PCS; Protocols for mobile networks.
• Communication systems for virtual reality.
• Audio-visual network architecture. Cross analog and digital transmission network (CrossOver Net); audio-visual communication protocol modelling on the OSIreference model.

We are doing collaborative research with several Japanese and foreign universities and research centers. In Japan, our partner researchers work in Shizuoka, Tohoku and Osaka Universities and the Advanced Institute of Communications in Sendai. Overseas, we collaborate with Protocol Test Center in Montreal, Canada; Sherbrooke University in Sherbrooke, Canada, Omnipoint Corporation in Colorado Springs, U.S.A; Ege University in Izmir, Turkey; and GMD National Center for Information Technology in Darmstadt, Germany.

The Computer Communications laboratory presently has the following equipment and software systems:

Equipment:

1. Multimedia workstations 2 SGI Indy
   
2. Protocol testing workstation Sun SPARCstation 10(2CPU)
   
3. Network management workstation Sun SPARCstation 10
   
4. GUI Modelling workstation Sun SPARCstation LX
   
5. SHN project server Sun SPARCstation IPX
   
6. Authoring system workstation Apple Quadra800
   
7. Windows application PC Gateway 2000
   
8. DTP PC Dynabook V486A x 2
   
9. FORE ATM Switch ASX-200

Software Systems:

1. GUI design tool Syclops2
   
2. EUC platform ATSON-1
   
3. Network management tool SunNet Manager
   
4. Simulation tool SES/ Workbench
   
5. Real-time programming tool SDT

Refereed Proceeding Papers

1. M. Bilgic and B. Sarikaya. Performance evaluation of high-speed multilayered protocol implem entations. In A. Lehmann A. R. Kaylan and T. I. Oren, editors, ESS'94 European Simulation Symposium, pages 283--287. Simulation Councils, Inc., Bosphorus University Press, October 1994.

   A new method of performance evaluation of communication systems is presented. Each protocol layer is modeled as a collection of five communicating finite-state machines consisting of initiator/ responder entities, their respective users and an underlying service. In order to verify the analytical results, a simulation model based on the same abstract Markov chain is used. The Markov chain is transformed into a collection of VHDL blocks. A library of different types of blocks are generated to model the processing associated with the states of the abstract Markov chain as collections of tasks.

2. K. Naik and B. Sarikaya. Protocol conformance test case verification using timed-transitio ns. In S. T. Vuong and S. T. Chanson, editors, Protocol Specification, Testing and Verification XIV, pages 103--118. IFIP, Chapman Hall, June 1994.

   We develop a methodology to verify correctness of test cases designed to check timed behaviour of protocol implementations. The verification process consists of four steps. First, we model a protocol specification, a test case, and an underlying service provider as Timed Extended Finite-State Machines (TEFSM) and define the resulting system as a Test Verification System (TVS). Next, we algorithmically obtain a model, i.e. a predicated global state space, from the TVS. Test case properties are formulated in terms of safety and liveness using branching time temporal logic. Finally we verify the test case properties on the model of the TVS using a model checking algorithm. We apply the verification technique to a test case for the Inres protocol. A few errors are detected in the design of the test case. We observe that without the use of TEFSM model, it would not have been possible to detect any time related errors in the test case.

3. M. Barbeau and B. Sarikaya. An approach for conformance testing of mib implementations. In 4th IFIP/IEEE International Symposium on Integrated Network Management, pages 103--118. IFIP/IEEE, IEEE, May 1995.

   A methodology is presented to test the conformity of managed nodes to network management standards in the SNMP framework. The first phase of the methodology consists of an object-oriented modelling of the managed node using class diagrams and SDL-92 language. The second phase takes the abstract model to systematically generate test suites. The approach is based on ISO's conformance testing methodology. Test cases are expressed in the Tree and Tabular Combined Notation (TTCN). The approach is illustrated with a recently developed Management Information Base (MIB) for the management of ATM permanent virtual links.

Grants

1. Behcet Sarikaya. Evaluation of itecs, an integrated environment for communication software design sponsored by advanced intelligent communications (aic) system laboratories, sendai, miyagi ken. Commissioned research 731, Commissioned research, April 1994.

1. Behcet Sarikaya, June 1994.

   Research Stay in University of Aizu of Olaf Henniger, a PhD. Student at Magdeburg University, Magdeburg, Germany from June 1994 until March 15, 1995 sponsored by DAAD Doctoral Scholarship of German Government.

2. Behcet Sarikaya, April 1994.

   International Conference Program Committee Memberships: IWPTS'94, Tokyo, Japan, November 1994, 7th SDL Forum, Oslo, Japan, September 1995, CFIP'95, Rennes, France, May 1995, IWPTS'95, Paris, France, September 1995, FORTE'95, Montreal, Canada, October 1995.

3. Behcet Sarikaya, April 1994. Paper Refereeing: IEEE Software Magazine, Computer Communications.

4. Behcet Sarikaya, December 1994.

   Conference Organization: International Conference on Multimedia Networking'95, Program Chair.