Browsing by Author "Yen, LH"

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A causal multicast protocol for mobile distributed systems
(2000-12-01)
Chi, KH
;
Yen, LH
;
Tseng, CC
;
Huang, TL
;
資訊工程學系
Causal message ordering in the context of group communication ensures that ail the message receivers observe consistent ordering of events affecting a group as a whole. This paper presents a scalable causal multicast protocol for mobile distributed computing systems. In our protocol, only a Dart of the mobility agents in the system is involved in group computations and the resulting size of control information in messages can be kept small. Our protocol can outperform qualitatively the counterparts in terms of communication overhead and hand-off complexity An analytical model is also developed to evaluate our proposal. The performance results show that the proposed protocol is promising.
Resetting vector clocks in distributed systems
(1997-05-25)
Yen, LH
;
Huang, TL
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
This paper establishes the necessary and sufficient condition for a correct clock resetting such that the functionality of vector clocks can be preserved. A clock reset protocol is presented with its applicability and limitation discussed. Our result indicates that for some applications, the potential of clock overflow can be completely prevented by carefully choosing the condition for initiating the clock reset protocol. (C) 1997 Academic Press.
Resetting vector clocks in distributed systems
(1997-05-25)
Yen, LH
;
Huang, TL
;
資訊工程學系
;
Department of Computer Science
This paper establishes the necessary and sufficient condition for a correct clock resetting such that the functionality of vector clocks can be preserved. A clock reset protocol is presented with its applicability and limitation discussed. Our result indicates that for some applications, the potential of clock overflow can be completely prevented by carefully choosing the condition for initiating the clock reset protocol. (C) 1997 Academic Press.
Topology-aided cross-layer fast handoff designs for IEEE 802.11/Mobile IP environments
(2005-12-01)
Tseng, CC
;
Yen, LH
;
Chang, HH
;
Hsu, KC
;
交大名義發表
This study first reviews state-of-the-art fast handoff techniques for IEEE 802.11 or Mobile IP networks. Based on that review, topology-aided cross-layer fast handoff designs are proposed for Mobile IP over IEEE 802.11 networks. Time-sensitive applications, such as voice over IP (VoIP), cannot tolerate the long layer-2. plus layer-3 handoff delays that arise in IEEE 802.11/Mobile IP environments. Cross-layer designs are increasingly adopted to shorten the handoff latency time. Handoff-related layer-2 triggers may reduce the delay between layer-2 handoff completion and the associated layer-3 handoff activation. Cross-layer topology information, such as the association between 802.11 access points and Mobile IP mobility agents, together with layer-2 triggers, can be utilized by a mobile node to start layer-3 handoff-related activities, such as agent discovery, address configuration, and registration, in parallel with or prior to those of layer-2 handoff. Experimental results indicate that the whole handoff delay can meet the delay requirement of VoIP applications when layer-3 handoff activities occur prior to layer-2 handoffs.