一個站台/主機可以藉由多重定址(multihoming)技術的使用，以同時經由多個網際網路服務提供者(ISPs)的方式連線到網際網路，也因此可以達到網路容錯、負載平衡、以及多路徑資料傳輸之功能。在本論文中，我們將研究並探討多重定址技術的相關研究及課題。我們發展了在網路層(network layer)及傳輸層(transport layer)上使用多重定址技術實現網路容錯、負載平衡、以及多路徑資料傳輸的方法，另外並以實作的方式探討如何實際應用多重定址技術。

首先，我們提出了一個複合式的IPv6多重定址技術。該技術結合了以主機導向及路由器導向為基礎的方法，並結合了這兩種方法的優點。在我們的設計中，我們使用網際網路控制訊息通訊協定中(ICMPv6)的路由器通告(router advertisement)以實現在IPv6網路中路由器以及主機間多重定址訊息的交換。我們亦實作這個系統，定名為”MultiGate6”。該系統提供了路由器層級以及主機層級的網路容錯及負載平衡功能。在多重定址環境下的主機因此可以同時經由不同的線路連線到網際網路。此外，該系統並提供了五種負載平衡的原則以達到避免單一線路的壅塞，並得以更有效率的充分運用所有線路的頻寬

接著，我們將焦點放在支援多重定址技術的流控制通訊協定(SCTP, Stream Control Transmission Protocol)在行動網路中的課題上。SCTP是一個支援多重定址技術的通訊協定。在本論文中，我們提出了一個新的SCTP延伸通訊協定，名為”M2-SCTP”。 M2-SCTP的主要功能在於提供一個行動節點在無線行動網路中實現多路徑資料傳輸及路徑換手機制。這是因為在行動網路中，一個行動節點所使用的傳輸路徑可能會因為行動節點的移動而改變，因此必須解決路徑換手的問題。此外，我們探討了四個主要課題：(1)多路徑資料傳輸模式的選擇，(2)導因於舊路徑上SACK (Selective Acknowledgement)遺失的非必要重傳問題，(3)導因於舊路徑上資料遺失的重傳及不必要的壅塞窗(CWND)衰減，以及(4)導因於路徑換手時的資料失序問題。我們並針對了這些課題，設計並修改原SCTP相關的處理機制以及演算法以解決這些問題。此外，我們並為M2-SCTP設計了一套應用動態網域名稱系統(dynamic DNS)的定位機制。

在探討如何實際應用多重定址技術方面，我們實作了兩個系統，分別為(一)NeTSurv系統及(二)MOVIDEO系統。在NeTSurv系統中，我們將多重定址技術應用在以IP為基礎之監控系統上(IP-based surveillance system)。由於目前的監控系統的發展主要以IP為基礎，因此如IP網路因故斷線，將造成監控系統功能的癱瘓。然而，目前相關的研究並沒有探討到這個嚴重的問題。我們探討可能的網路中斷情境，並解決可能發生的問題。我們使用了多重定址技術以加強監控系統的網路容錯功能。藉由我們所發展的雙重容錯機制，當主要線路中斷時，系統將自動切換至備援線路、並保持監控視訊的連線不中斷，而因網路斷線而遺失的監控畫面資料亦會被自動修復。此外，我們也為監控系統發展一套負載平衡的機制，當有很多客戶端連線監控時，連線將被分均分散在多條線路上，以避免單一線路擁塞而造成監控畫面品質不佳的狀況。而在MOVIDEO系統中，我們探討如何以SCTP實作視訊串流熱插拔機制(video streaming hot-plug)。視訊串流熱插拔的功能在於當主機於有線網路切換至無線網路、無線網路切換至另一無線網路、或是從無線網路切換回有線網路時，依然能夠保持視訊串流的播放連續而不中斷。我們採用了SCTP的兩個延伸通訊協定”SCTP ADDIP Extension”及”PR-SCTP”實作我們的視訊串流熱插拔系統”MOVIDEO”。SCTP ADDIP Extension的主要功能在於讓一個主機可以動態的新增、刪除、改變其使用的主要傳輸路徑，而PR-SCTP則提供了部份可靠的資料傳輸功能，用以傳輸視訊資料。我們使用了不同的主要路徑切換方式來衡量MOVIDEO系統，而實驗結果也證明我們所發展的MOVIDEO視訊串流熱插拔技術可以有效地讓主機於有線及無線網路間切換時能保持視訊不間斷且流暢地播放。

Multihoming allows a site/host to connect to multiple Internet Service Providers (ISPs) simultaneously. Network fault tolerance (service resilience), load balancing, and concurrent multi-path transmission can thus be achieved using the multihoming technique. In this dissertation, related works and research issues of the multihoming technology are studied and investigated. Approaches to achieve network fault tolerance, link load balance, and concurrent multi-path transmission are developed using the multihoming technology network layer and transport layer. Implementations are also demonstrated in this dissertation to investigate how to apply the multihoming technology to real applications.

At the network layer, a hybrid IPv6 multihoming approach, which combines the host-based multihoming approach and the router-based multihoming approach, is proposed. In the proposed design, Router Advertisements defined in Internet Control Message Protocol version 6 (ICMPv6) is adopted to handle the multihoming message exchange between the router and the hosts within the IPv6 multihomed network. The corresponding system implementation called ”MultiGate6” offers fault tolerance, load balancing, and provider independence services to both site and host levels. Hosts within the multihomed network are able to establish connections through multiple links simultaneously. With the five load balancing policies provided in MultiGate6, congestion of a single link can be prevented and thus bandwidths of links can be utilized more efficiently.

At the transport layer, we focus on the mobility issues of SCTP (Stream Control Transmission Protocol) multi-path transmission. SCTP is a transport protocol which supports multihoming in nature. In this dissertation, M2-SCTP (Mobile Multipath - Stream Control Transmission Protocol) is proposed to allow a host to perform (multi-)path handover when multi-path transmission is adopted in wireless mobile networks. Four concerns related to path handover that are addressed and resolved in this dissertation include (1) transmission mode selection in wireless networks, (2) spurious retransmissions due to failed SACK (Selective Acknowledgement) transmission at the old path, (3) retransmissions of data lost before path handover and unnecessary CWND (Congestion Window) reductions, and (4) the reordering problem due to path handover. Based on the mechanisms devised to solve the path handover problem, the M2-SCTP multi-path handover mechanism is also devised.

Furthermore, to investigate how to apply multihoming to real applications, two systems, i.e., (1) NeTSurv, and (2) MOVIDEO, are implemented. For the NeTSurv system, we apply the idea of dual-multihoming to IP-based surveillance system. Possible network failure scenarios are investigated and determined. A multihomed network-fault-tolerant IP-based surveillance (NeTSurv) system is designed and implemented. A multihome-based approach is adopted and a two-level fault tolerance mechanism is developed to solve the connectivity issue and the continuity issue of video playout for different link failure scenarios. With the devised mechanism, the lost surveillance video data resulted from abrupt link failure can be recovered. A load balance mechanism is also devised for the NeTSurv system to distribute the load across multiple links. For the MOVIDEO system, video streaming hot-plug mechanisms using SCTP are investigated. Video streaming hot-plug is defined as keeping video streaming to be continuous when a host is switched between wired and wireless networks. Two SCTP extensions, the SCTP ADDIP extension and (Partially Reliable) PR-SCTP are adopted to design and implement the corresponding system called “MOVIDEO”. Performance evaluation of the “MOVIDEO” system is provided in this dissertation. The experimental results demonstrate that, using the proposed SCTP-based video streaming hot-plug mechanism, the connection of the video streaming service would not be broken and the playout of the video can be kept smooth during the process of video streaming hot-plug.

[1] The IETF IPv6 Multihoming Working Group,
http://www.ietf.org/html.charters/multi6-charter.html.
[2] Stewart, R., Xie, Q., Morneault, K., Sharp, C., Schwarzbauer, H., Taylor, T., Rytina,
I., Kalla, M., Zhang, L. and Paxson, V. (2000) Stream Control Transmission Protocol,
RFC 2960, IETF.
[3] J. Yu, “IPv6 Multihoming with Route Aggregation,” IETF Internet Draft: draft-ietfipngwgipv6multihome-
with-aggr-01.txt, Aug. 2000.
[4] M. Bagnulo, A. Garcia-Martinez, A. Azcorra, D. Larrabeiti, “Survey on Proposed
IPv6 Multi-Homing Network Level Mechanisms,” IETF Internet Draft draft-bagnulomulti6-
survey6-00.txt, July 2001.
[5] D. Johnson, S. Deering, “Reserved IPv6 Subnet Anycast Addresses,” IETF RFC 2526,
Mar. 1999.
[6] IETF Internet-Draft: Host Identity Protocol, http://www.ietf.org/internet-drafts/draftietf-
hip-base-00.txt
[7] IETF Inter-Darft: Architectural Commentary on Site Multi-homing using a Level 3
Shim, http://www.potaroo.net/drafts/draft-ietf-shim6-arch-00.html
[8] Internet-Draft: LIN6(Location Independent Networking for IPv6).
http://www.lin6.net/draft/draft-teraoka-multi6-lin6-00.txt
[9] D. Johnson, C. Perkins, J. Arkko, “Mobility Support in IPv6,” IETF RFC 3775, June
2004.
[10] P. Ferguson, D. Senie, “Network Ingress Filtering: Defeating Denial of Service Attacks
which employ IP Source Address Spoofing,” IETF RFC 2827, May 2000.
[11] N. Yamai, K. Okayama, H. Shimamoto, and T. Okamoto, “A Dynamic Traffic Sharing
with Minimal Administration on Multihomed Networks,” Proc. of IEEE International
Conference on Communications 2001 (ICC2001), Vol.5, pp.1506-1510, June 2001.
[12] Y. Hori, K. Onimaru, T. Ikenaga, and Y. Oie, “Design and Implementation of IPv6
gateway allowing effective use of multihome network,” IEEE PACRIM’03, pp.601-
604, 28-30 Aug. 2003, Victoria, B.C., Canada , August 2003.
[13] L. Coene, “Stream Control Transmission Protocol Applicability Statement.” RFC 3257,
IETF, April 2002.
[14] L. Ong and J. Yoakum, “An Introduction to the Stream Control Transmission Protocol
(SCTP),” RFC 3286, IETF, May 2002.
[15] A. L. Caro, J. R. Iyengar, and P. D. Amer et. al, “SCTP: a proposed standard for robust
internet data transport,” IEEE Computer, VOL. 36, NO. 11, pp. 56-63, November 2003.
[16] R. Stewart and C. Metz, “SCTP: New transport protocol for TCP/IP,” IEEE Internet
Computing, VOL. 5, NO. 6, pp. 64-69, November/December 2001.
[17] S. J. Fu and M. Atiquzzaman, “SCTP: State of the Art in Research, Products, and
Technical Challenges,” IEEE Communications Magazine, VOL. 42, NO. 4, pp. 64-76
April 2004.
[18] J. Andreas, et al., “SCTP- A Multi-Link End-to-End Protocol for IP-Based Networks,”
AEU -The International Journal of Electronics and Communications, pp. 46-54, February
2002.
[19] A. Jungmaier, M. Schopp, and M. Tuxen, “Performance Evaluation of the Stream Control
Transmission Protocol,” Proceedings of the 2000 IEEE Conference on High Perfomance
Switching and Routing, Heidelberg, German, pp. 141-148, June 2000.
[20] A. Jungmaier, E.P Rathgeb, and M. Tuxen, “On the Use of SCTP in Failover Scenarios,”
Proceedings of the SCI 2002, Mobile/Wireless Computing and Communication
Systems II, VOL. X, Orlando, USA, pp. 363-368, July 2002.
[21] M. Allman, V. Paxson, and W. Stevens, “TCP Congestion Control,” RFC 2581, IETF,
April 1999.
[22] R. Stewart, M. Ramalho, and Q. Xie et. al., “Stream Control Transmission Protocol
(SCTP) Dynamic Address Reconfiguration,” draft-ietf-tsvwgaddip-sctp-15.txt, May
2006.
[23] M. Riegel, M. Tuexen, “Mobile SCTP,” draft-riegel-tuexen-mobile-sctp-07.txt, October
2006.
[24] S. J. Koh, et al., “Architecture of Mobile SCTP for IP Mobility Support,”
http://www.watersprings.org/pub/id/draft-sjkoh-mobile-sctp-mobileip-04.txt, June
2004
[25] S. J. Koh, M. J. Chang, and M. J. Lee, “mSCTP for Soft Handover in Transport Layer,”
IEEE Communications Letters, VOL 8, NO. 3, March 2004.
[26] W. Xing, H. Karl, and A. Wolisz, “M-SCTP: Design and Prototypical Implementation
of an End-to-End Mobility Concept,” Proceedings of 5th Intl Workshop: The Internet
Challenge - Technology and Applications, Berlin, Germany, October 2002.
[27] J. R. Iyengar, K. C. Shah, and P. D. Amer, “Concurrent Multipath Transfer Using SCTP
Multihoming Over Independent End-to-End Paths,” J. Iyengar, P. Amer, and R. Stewart,
IEEE/ACM Transactions on Networking (in press).
[28] G. Ye, T. N. Saadawi, and M. Lee, “IPCC-SCTP: An Enhancement to the Standard
SCTP to Support Multi-homing Efficiency,” IEEE International Conference on Performance,
Computing, and Communications, pp. 523-530, April 2004.
[29] A. Abd EI AI, T. Saadawi, M. Lee, “LS-SCTP: A Bandwidth Aggregation Technique
for Stream Control Transmission Protocol,” Computer Communications, VOL 27, NO.
10, pp. 1012-1024, 2004.
[30] C. Casetti and W. Gaiotto, “Westwood SCTP: Load Sharing over Multipaths using
Bandwidth-aware Source Scheduling,” IEEE 60th Vehicular Technology Conference,
VOL 4, pp. 3025-3029, September 2004.
[31] S. Kashihara, K. Iida, H. Koga, Y. Kadobayashi, and S. Yamaguchi, “Multi-Path Transmission
Algorithm for End-to-End Seamless Handover across Heterogeneous Wireless
Access Networks,” IEICE Transactions on Communications, VOL. E87-B, NO. 3, pp.
490-496, March 2004.
[32] R. Draves, “Default Address Selection for Internet Protocol version 6 (IPv6),” RFC
3484, IETF, Feb. 2003.
[33] A. Conta and S. Deering, “Internet Control Message Protocol (ICMPv6) for the Internet
Protocol Version 6 (IPv6) Specification,” RFC 2463, IETF, December 1998.
[34] B. A. Mah. pchar: a Tool for Measuring Internet Path Characteristics. February 1999.
[35] Linux IPv6 Router Advertisement Daemon (radvd),
http://v6web.litech.org/radvd/index.html.
[36] T. Narten, E. Nordmark and W. A. Simpson, “Neighbor Discovery for IP version 6
(IPv6),” RFC 2461.
[37] S. Thomson and T. Narten, “IPv6 Stateless Address Autoconfiguration,” RFC2462,
IETF, December 1998.
[38] http://www.ietf.org/html.charters/mip4-charter.html.
[39] http://www.ietf.org/html.charters/mip6-charter.html.
[40] http://www.ietf.org/html.charters/sip-charter.html.
[41] The Network Simulator ns-2, http://www.isi.edu/nsnam/ns.
[42] SCTP Module, http://pel.cis.udel.ed.
[43] Iperf, http://dast.nlanr.net/Projects/Iperf/.
[44] Stewart, R., Ramalho, M., Xie, Q., Tuexen, M. and Conard, P., “Stream Control Transmission
Protocol (SCTP) Partial Reliability Extension,” RFC 3758, IETF, 2004.
[45] sctplib-1.3.1, http://www.exp-math.uni-essen.de/ ajung/src/sctplib-1.3.1.tar.gz
[46] iwlist, http://linuxcommand.org/man pages/iwlist8.html.
[47] ethtool, http://sourceforge.net/project/showfiles.php?group id
=3242&package id=19201.