• Journal of Communications and Networks
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• v.7 no.3
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• pp.367-376
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• 2005

The smooth handoff supported by the route optimization extension to the mobile IP standard protocol should support a packet buffering mechanism at the base station (BS), in order to reduce the degradation in TCP performance caused by packet losses within mobile network environments. The purpose of packet buffering at the BS is to recover the packets dropped during intersubnetwork handoff by forwarding the packets buffered at the previous BS to the new BS. However, when the mobile host moves to a congested BS within a new foreign subnetwork, the buffered packets forwarded by the previous BS are likely to be dropped. This subsequently causes global synchronization to occur, resulting in the degradation of the wireless link in the congested BS, due to the increased congestion caused by the forwarded burst packets. Thus, in this paper, we propose an implicit priority forwarding (IPF) packet buffering scheme as a solution to this problem within mobile IP based networks. In the proposed IPF method, the previous BS implicitly marks the priority packets being used for inter-subnetwork handoff. Moreover, the proposed modified random early detection (M-RED) buffer at the new congested BS guarantees some degree of reliability to the priority packets. The simulation results show that the proposed IPF packet buffering scheme increases the wireless link utilization and, thus, it enhances the TCP throughput performance in the context of various intersubnetwork handoff cases.

• Journal of KIISE:Information Networking
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• v.33 no.5
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• pp.343-354
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• 2006

There has been much research efforts trying to integrate mobile IP that has been proposed to guarantee the mobility of mobile nodes on MANET (Mobile Ad Hoc Networks) and wired integrated networks. To support the mobility service of nodes in MIPMANET, this paper proposes MAAM(Mobility Agent Advertisement Mechanism) and AMAAM protocols. In MAAM, the mobility agent of the mobile IP can maintain the information of ad hoc networks by broadcasting advertisement messages periodically. AMAAM(Aggregation based Mobility Agent Advertisement Mechanism) is an enhancement of MAAM for reducing the number of transmission of advertisement messages by aggregating them. The proposed schemes are applied in MIPMANET for agent advertisement mechanism. For the performance evaluation of both protocols, we simulated them by NS2. We evaluate the protocols by ns2 with such performance metrics as packet delivery ratio, transmission throughput, and energy consumption.

• Journal of IKEEE
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• v.5 no.1 s.8
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• pp.8-15
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• 2001

This paper remarks IETF based requirements for IP/UDP/RTP header compression issued in 3GPP2 All IP Ad Hoc Meeting and protocol stacks of the next generation mobile station. All IP Network, for real time application such as Voice over IP (VoIP) multimedia services based on 3GPP2 3G cdma2000. Frames for various protocols expected in the All IP network Mobile Station (MS) are explained with several figures including the bit-for-bit notation of header format based on IETF draft of Robust Header Compression Working Group (ROHC). Especially, this paper includes problems of IS-707 Radio Link Protocol (RLP) for header compression which will be expected to modify in All IP network MS's medium access layer to accommodate real time packet data service[1]. And also, since PPP has also many problems in header compression and mobility aspects in MS protocol stacks for 3G cdma2000 packet data network based on Mobile IP (PN-4286)[2], we introduce the problem of solution for header compression of PPP. Finally. we suggest the guidelines for All IP network MS header compression about expected protocol stacks, radio resource efficiency and performance.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.205-218
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• 2012

Mobility management of the mobile nodes and provision of seamless handover is crucial to an efficient support for the global roaming of the mobile nodes in next-generation wireless networks. Mobile IPv6 and mobility management in extended IP layer, which highly depend on traffic characteristics and user mobility models, were proposed by the IETF. Therefore, to evaluate the in-depth performance about these factors is important. Generally, the performance of IPv6-based mobility management protocol is evaluated through simulation. This paper shows the correlation between network parameters and performance metrics through numerical results, which is investigated how influence handoff latency and packet loss. And this paper uses mathematical analysis of the system parameters, such as the subnet residence time, the packet arrival rate and delay in wireless connection through the analytical framework which evaluate the performance of IPv6-based mobility management protocol.

• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.627-636
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• 2002

In this paper, we investigate the interworking method between three transport mechanisms, that is, ATM transport, IP$_v$4 transport and Ip$_v$6transport, where these mechanisms are wholly used in a Mobile RAN (Radio Access Network). The proposed interworking method, called Triple Capable Node, is to implement three transport mechanisms simultaneously in a single node so that the node can communicate directly to other nodes having various transport mechanisms by using one of three transport mechanisms. In addition, we propose a dynamic algorithm which selects one among multiple transport mechanisms at run time in order to achieve better communication performance.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.4
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• pp.71-77
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• 2011

In this paper, we propose a conversational quality measurement (CQM) system for providing the objective QoS of high quality mobile VoIP voice telecommunication. For measuring the conversational quality, the VoIP telecommunication system is implemented in two smart phones connected with VoIP. The VoIP telecommunication system consists of echo cancellation, noise reduction, speech encoding/decoding, packet generation with RTP (Real-Time Protocol), jitter buffer control and POS (Play-out Schedule) with LC (loss Concealment). The CQM system is connected to a microphone and a speaker of each smart phone. The voice signal of each speaker is recorded and used to measure CE (Conversational Efficiency), CS (Conversational Symmetry), PESQ (Perceptual Evaluation of Speech Quality) and CE-CS-PESQ correlation. We prove the CQM system by measuring CE, CS and PESQ under various SNR, delay and loss due to IP network environment.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.58-60
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• 2003

Mobile IP는 현재의 인터넷에서 노드가 링크를 변화시킬 때 통신이 지속 될 수 있도록 이동성(Mobility)을 제공하기 위한 방안이다. Mobile IP는 MN(Mobile Node)이 HA(Home Agent) 와 FA(Foreign Agent)사이에서 링크를 변화시킬 때 CN(Correspondent Node)과 지속적인 통신을 할 수 있도록 한다. 그러나 FA에서 FA로 MN이 노드의 위치를 바꿀 때에는 핸드오프(Handoff)가 발생하여 패킷이 손실 될 수도 있다. 본 논문은 MN이 FA에서 다른 FA로 이동할 때 발생하는 패킷 손실과 순서변경에 대한 경우를 살펴 이를 해결하기 위한 Seamless 핸드오프 프로토콜을 기술하고 이를 검증한다.

• Journal of Information Processing Systems
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• v.4 no.3
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• pp.87-96
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• 2008

This paper analyzes the handover latency of Mobile IP and mobile SCTP over IPv6 networks. The analytical results are compared with the performance by experiment over Linux testbed. For analysis, we consider the two handover scenarios: horizontal handover and vertical handover. From the results, we see that mSCTP can provide smaller handover latency than Mobile IP. Moreover, mSCTP can give much smaller handover latency for vertical handover, compared to horizontal handover.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.29-36
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• 2007

IP paging strategy, one of the solutions for derived problems in IP mobility support protocol, reduces the messages and the overheads over the network, since there is not registration procedure when a mobile terminal moves into a new router within the same paging area. However, the fact that the mobile terminals with the previous strategy consume electrical power continuously for paging signal reception obstructs the application of IP paging strategy to the IP-based wireless sensor networks. In this paper, we propose a discontinuous paging reception strategy based on the characteristics of the wireless sensor networks and their mobile terminals. As a result of the mathematical analysis, the proposed strategy significantly reduces the terminals' power consumption. In addition, by setting the relating parameters as appropriate values, the proposed strategy can be switched to the continuous reception strategy, or can be adjusted to limit the terminals' power consumption or paging delay.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.886-889
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• 2008

There are Proxy Mobile IPv6(PMIPv6) and Network Mobility Basic Support Protocol (NEMO BSP) for more enhanced mobility support. These have a common purpose to support seamless IP mobility at network infrastructure level whenever mobile nodes(MNs) move between foreign networks. But it is different that the NEMO BSP supports an entire network's mobility, while the PMIPv6 supports only a single MN's mobility. In this paper, a new scheme is proposed to guarantee an interoperability of PMIPv6 and NEMO BSP.