Browsing by Author "Ho, JM"

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Experience in designing a using TCP as transport protocol VOD system over a dedicated network
(1998-11-01)
Lu, DJ
;
Wang, YC
;
Ho, JM
;
Chen, MC
;
Ko, MT
In this paper we address the problem of designing a TCP[11] and IP[10] (TCP/IP for short) based video on demand (VOD for short) system over a dedicated network based on standard internet protocols, ie., Transmission Control Protocol (TCP for short, IETF RFC 793[11]) and Internet Protocol (IP for short, IETF RFC 791[10]). TCP and IP are usually refered together as TCP/IP. Despite of the general belief that TCP/IP is not suitable for real-time multimedia applications, after testing in laboratory environment for about one year we are confident in announcing that our prototype is both efficient and reliable. This success depends on several important factors. First of all, the system operates on a dedicated network in which there exists no other traffic except a light of background traffic generated by the Ether Switch the major network component used by our prototype. Second system overhead due to the VOD server and the network adaptor card is minimized Third, we maximize disk bandwidth by implementing a proprietary disk file system. Our experiment shows that it requires only about 330 KBytes at the client buffer to smooth packet delay jitters. In our experimental environment, due to resource limitations, up to 40 clients had been tested successfully. By looking at network bandwidth and CPU utilization, we estimate that a single VOD sewer should be able to handle more than 40 interactive clients playing MPEG-1 system streams simultaneously.
Performance analysis for voice/data integration on a finite-buffer mobile system
(2000-03-01)
Haung, YR
;
Lin, YB
;
Ho, JM
;
資訊工程學系
;
Department of Computer Science
Personal communication service (PCS) networks offer mobile users diverse telecommunication applications, such as voice, data, and image, with different bandwidth and quality-of-service (QoS) requirements. This paper proposes an analytical model to investigate the performance of an integrated voice/data mobile network with finite data buffer in terms of voice-call blocking probability, data loss probability, and mean data delay. The model is based on the movable-boundary scheme that dynamically adjusts the number of channels for voice and data traffic. With the movable-boundary scheme, the bandwidth can be utilized efficiently while satisfying the QoS requirements for voice and data traffic. Using our model, the impact of hot-spot traffic in the heterogeneous PCS networks, in which the parameters (e.g., number of channels, voice, and data arrival rates) of cells can be varied, can be effectively analyzed. In addition, an iterative algorithm based on our model is proposed to determine the handoff traffic, which computes the system performance in polynomial-bounded time. The analytical model is validated by simulation.