Browsing by Author "Lee, GC"

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HLR replication protocols for global mobility management in PCS networks
(2003-01-01)
Lee, GC
;
Wang, TP
;
Tseng, CC
;
資訊工程學系
;
Department of Computer Science
The new trend for PCS networks is to provide mobile users with large-scale mobile capability across many service areas. In this scenario, global database management for PCS networks has become an increasingly important research issue. In this paper, we examined two replicated database strategies, single-replica (SR) and multiple-replica (MR), for large-scale mobility of per-user data management in personal communication networks. The SR strategy uses a single replica approach of HLR. The MR strategy replicates the per-user data of HLR in many regions. The two strategies are based a partial replication scheme, and a primary copy method is used to maintain replicas' consistency. Our numerical results show that the MR strategy outperforms the SR strategy in most situations; however, it may be worse when the probability of a mobile user visiting a foreign region is high and the query rates from other foreign regions are low. Additionally, the number of replicas should be compact in the MR strategy in order to achieve a reasonable query response time. Therefore, we propose an adaptive multiple replication protocol to choose a suitable replication strategy and to decide the optimized number of replicas.
HMRSVP: A hierarchical mobile RSVP protocol
(2003)
Tseng, CC
;
Lee, GC
;
Liu, RS
;
Wang, TP
;
資訊工程學系
In this paper, we propose a hierarchical Mobile RSVP (HMRSVP) that can achieve mobility independent QoS-guaranteed services in mobile computing environments. The HMRSVP integrates RSVP with Mobile IP regional registration and makes advance resource reservations only when an inter-region movement may possibly occur. We first show that, by NS simulator, our HMRSVP can achieve the same QoS guarantees as MRSVP does with fewer resource reservations. Then, we show that HMRSVP outperforms MRSVP in terms of reservation blocking, forced termination and session completion probabilities.
HMRSVP: A hierarchical Mobile RSVP Protocol
(2001-01-01)
Tseng, CC
;
Lee, GC
;
Liu, RS
;
資訊工程學系
;
Department of Computer Science
In this paper we propose a hierarchical Mobile RSVP (HMRSVP) that can achieve mobility, independent QoS guaranteed services in mobile computing environments. The HMRSVP integrates RSVP with Mobile IP regional registration and makes advance resource reservations only when an inter-region movement may possibly happen. We first show that, by NS simulation, our HMRSVP can achieve the same QoS guarantees as MRSVP with fewer resource reservations. Then, we show that HMRSVP outperforms MRSVP in terms of reservation blocking, forced termination and session completion probabilities.
HMRSVP: A hierarchical Mobile RSVP Protocol
(2001-01-01)
Tseng, CC
;
Lee, GC
;
Liu, RS
In this paper we propose a hierarchical Mobile RSVP (HMRSVP) that can achieve mobility, independent QoS guaranteed services in mobile computing environments. The HMRSVP integrates RSVP with Mobile IP regional registration and makes advance resource reservations only when an inter-region movement may possibly happen. We first show that, by NS simulation, our HMRSVP can achieve the same QoS guarantees as MRSVP with fewer resource reservations. Then, we show that HMRSVP outperforms MRSVP in terms of reservation blocking, forced termination and session completion probabilities.
Resetting forwarding pointers with delay propagation schemes in a distributed HLR environment
(2001-04-01)
Lee, GC
;
Wang, TP
;
Tseng, CC
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose a new location tracking method for pointer forwarding with distributed HLRs schemes to decrease the location tracking cost. Similar to the distributed HLR schemes, the location information is replicated on all HLRs in our scheme. However, unlike the traditional distributed HLR schemes, we propagate the most recent location changes from an HLR to reset the forwarding pointers in other HLRs, and thus reduce the cost of location tracking for call deliveries. The signaling cost of location propagation may be too costly to be practical. Therefore, we allow some inconsistency to exist among the location data of HLRs and defer the propagation of location changes to reduce the propagation cost. Three delay propagation policies are also proposed and analyzed using simulation. The performance result shows that the delay propagation policies reduce the propagation cost and the propagation resetting process degrades the location tracking cost. Our method preserves a low total cost for call deliveries, registrations and propagations in distributed HLRs.
Resource reservation with pointer forwarding schemes for the mobile RSVP
(2001-07-01)
Lee, GC
;
Wang, TP
;
Tseng, CC
;
資訊工程學系
;
Department of Computer Science
In this letter, we propose a pointer forwarding scheme for the Mobile Resource reSerVation Protocol (MRSVP) to reduce the resource reservation cost on the wireless Internet, We show the pointer forwarding scheme could significantly degrade the reservation cost when a mobile host performs locality movement.