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그룹이동성및펨토셀이동성기술 스마트모바일서비스및네트워크기술워크숍 2010. 06. 11.

kr Wireless Information and Network Engineering

1 그룹이동성및펨토셀이동성기술 스마트모바일서비스및네트워크기술워크숍 고려대학교하나스퀘어 Jae-Hyun Kim Wireless Information and Network Engineering Research Lab. School of Electrical and Computer Engineering Ajou University, Korea

2 목차 이동성의개념및분류 계층별이동성관리기술 L2 mobility management L3 mobility management L4 mobility management L5 mobility management 그룹이동성관리기술 1

Wi-Fi, WCDMA, HSPA, LTE, WiBro, ) 이동단말의다양화 (smart

3 이동성의개념및분류 이동성 (mobility) 이란? 사용자또는이동단말의장소와통신환경의변화에관계없이통신서비스를제공할수있는능력 (ITU-T T Q.1706/Y.2801) 1706/Y2801) 이동성관리의필요성 접속기술의다양화 (Bluetooth, Wi-Fi, WCDMA, HSPA, LTE, WiBro, ) 이동단말의다양화 (smart phone, PDA, net-book, laptop, ) 실시간서비스요구증가 ( 음성 / 영상통화, 방송, ) - ITU-T Recommendation Q.1706/Y.2801, Mobility management requirements for NGN 2

4 이동성의개념및분류 이동주체에따른이동성분류 Terminal mobility 통신서비스를이용중인단말이다른위치로이동하였거나이동중인경우에도계속적인서비스를제공할수있는능력 Network mobility 버스, 기차와같이다수의단말이같은패턴으로이동하는경우에네트워크의이동에따라서접속점을변경할수있는능력 Personal mobility 사용자가네트워크에접속가능한단말을다수보유한경우, 사용자가어떤단말을통해서접속하든지 personal identifier를기반으로동일한서비스를제공할수있는능력 Service mobility 사용자의위치와단말의종류에관계없이사용자가가입한특정서비스를제공할수있는능력 - ITU-T Recommendation Q.1706/Y.2801, Mobility management requirements for NGN 3

5 이동성의개념및분류 서비스연속성에따른이동성분류 Service continuity Service discontinuity Seamless handover 단말의이동시서비스의품질에아 무런영향을미치지않고사용중인 서비스를끊김없이유지할수있는경우 Nomadism 단말의이동시기존의서비스세션은완전히정지시키고, 새로운세션을만들어서서비스를제공할수있는경우 Handover 단말의이동시사용중인서비스의품질이일부저하되지만사용중인서비스를유지할수있는경우 Portability 단말의이동시접속지점에따라 user identifier 또는 address를할당하는능력 - ITU-T Recommendation Q.1706/Y.2801, Mobility management requirements for NGN 4

6 이동성의개념및분류 접속기술변경에따른이동성분류 Horizontal mobility 같은접속기술을사용하는접속지점간의이동성 Vertical mobility 다른접속기술을사용하는접속지점간의이동성 이동성관리기술의분류 Location management 이동단말의현재위치파악, 이동경로추적 Location registration Call delivery / paging Handover management 이동단말의이동시서비스연속성보장 L2 link configuration IP address configuration Location management와함께수행 - ITU-T Recommendation Q.1706/Y.2801, Mobility management requirements for NGN 5

7 이동성관리를위한요구사항 도메인에따른이동성관리분류 이동성관리요구사항의차이점 운영 / 관리 접속기술 Inter-CN 상이동일 / 상이 Inter-AN 동일동일 / 상이 Intra-AN 동일동일 - ITU-T Recommendation Q.1706/Y.2801, Mobility management requirements for NGN 6

8 이동성관리를위한요구사항 일반적인요구사항 Harmonization with IP-based networks Separation of control and transport functions (for efficiency & scalability) Provision of a location management function Provision of mechanisms for identification of users/terminals QoS support Interworking with established AAA and security schemes Location privacy Support of network mobility Support of ad hoc networks Resource optimization (to save power consumption & signaling overhead) Support of IPv4/IPv6 and public/private addresses Provision of personal and service mobility User data accessibility (for customized service) Support of several kinds of mobile endpoints Maintenance of binding information - ITU-T Recommendation Q.1706/Y.2801, Mobility management requirements for NGN 7

9 이동성관리를위한요구사항 Inter-CN 요구사항 Independence from network access technologies Effective interworking with existing MM protocols Inter-AN 요구사항 Independence from network access technologies Provision of mechanisms for context transfer (QoS level, security method, AAA mechanism, compression type in use, ) Effective interworking with existing MM protocols Provision of a handover management function for seamless services Support of policy-based and dynamic network selection Intra-AN 요구사항 Provision of mechanisms for context transfer Provision of a handover management function for seamless services - ITU-T Recommendation Q.1706/Y.2801, Mobility management requirements for NGN 8

10 계층별이동성관리기술 L2 mobility management 기존접속지점과 L2 링크해제, 새로운접속지점과 L2 링크연결 접속기술별로별도의절차가정의되어있음 WLAN, WCDMA, WiBro, L3 mobility management 이동단말이서로다른 IP 도메인으로이동한경우 IP 주소변경 MIP, HMIP, PMIP, Vertical mobility 정보제공기술 MIH 멀티호밍지원 LISP, HIP, MOBIKE L4 mobility management 다중세션연결 / 관리 SCTP, msctp L5 mobility management 서비스별 QoS 요구사항을고려한멀티호밍기반이동성관리 User-centric terminal-controlled mobility 9

11 L2 Mobility Management 상 / 하향링크고려핸드오버기법 핸드오버예상시간협상기법 펨토셀선택적스캐닝기법 10

12 L2 상 / 하향링크고려핸드오버 ( 아주대 ) OFDMA 에서상하향채널모델링 핸드오버초기화및결정에상하향채널정보를모두이용 상향채널정보를이용한핸드오버레인징송신전력조절 < 상향링크품질저하로인한 Outage 감소로 Handover outage 성능향상 > CDF Conventional handover Hybrid handover without proposed scheme Hybrid handover with proposed scheme Service disruption time (msec) < 핸드오버레인징성공율증가로 Service interruption time 성능향상 > - J. S. Kim and J. H. Kim, "Handover Scheme using Uplink and Downlink Channel Information in IEEE e Systmes," in Proc. VTC 2010-spring, Taipei, Taiwan, May

13 L2 핸드오버예상시간협상기법 ( 아주대 ) IEEE e 시스템에서핸드오버메시지손실에의한핸드오버지연시간증가 핸드오버예상시간협상을통해핸드오버메시지손실발생시빠른재전송가능 RTT calculation Serving BS algorithm MS 로전송되는하향채널패킷의 RTT 계산 1 T T T T RTT RTT ACK Data Backbone delay calculation l BS간의핸드오버메시지전송지연계산 T T T ' BD TS TS Estimated Handover Time Calculation MS 의 Fast_Ranging_IE() 수신가능시간계산 T Max{ T, T, T T T } HO residual, S BD RTT Sync Margin Target BS algorithm Residual Estimated Handover Time Calculation Fast_Ranging_IE() 전송예정시간계산 T T T T T29 Time out Residual, N ET LT TS MOB_BSHO-RSPBSHO 전송후 MOB_HO-IND 수신 timer 가완료되면핸드오버메시지의손실로가정하고재전송 MOB_BSHO-RSPBSHO 의손실 : T Residual, S 과 Action time, Resource retain time 을갱신하여 MOB_BSHO-RSP/HO-prenotification-confirm을재전송 MOB_HO-IND 의손실 : Target BS 는 RNG-REQ 를수신하면 Fast_Ranging_IE() 의전송을취소 - H. J. Lee and J. H. Kim, "A Handover Time Negotiation for Seamless Service in IEEE E," in Proc. MILCOM 2008, San Diego, USA, Nov

14 L2 핸드오버예상시간협상기법 ( 아주대 ) 서비스단절시간비교 기존핸드오버기법 핸드오버예상시간협상기법 Traffic Latency Signal Latency Traffic Latency Signal Latency 0.3 Handover Message Failure 0.3 Handover Message Failure Laten ncy (second) Power Adjustment Failure Laten ncy (second) Power Adjustment Failure 0.1 Handover Success 0.1 Handover Success Time (second) Time (second) 트래픽지연 시그널지연 트래픽지연 시그널지연 평균 (msec) 최소 (msec) % (msec) 평균 (msec) 최소 (msec) % (msec) 최대 (msec) prob{<150msec}(%) 최대 (msec) prob{<150msec} (%) H. J. Lee and J. H. Kim, "A Handover Time Negotiation for Seamless Service in IEEE E," in Proc. MILCOM 2008, San Diego, USA, Nov

15 L2 펨토셀선택적스캐닝기법 ( 아주대 ) IEEE e 시스템에서다수의펨토셀로인한스캐닝오버헤드증가 ting control message ove erhead (bits) 9 x IEEE e - MAX Two-step scanning - MAX Selectve scanning - MAX IEEE e - MIN Two-step scanning - MIN Selective scanning - MIN 펨토셀 BSID와메크로셀 BSID 매치, 상향링크신호모니터링을통해접속가능성이높은펨토셀만선택하여 스캐닝수행 2 스캐닝대상셀의수를줄임으로써메시지오버헤드, 1 스캐닝소요시간감소 Broadcas Number of Femtocell BSs (CSG+OSG) < Control message overhead : IEEE e 기존절차대비 73.1% 감소 > 2 x 104 Scan duration (sec) IEEE e Two-step scanning Selectve scanning < 제안 CSG femtocell 의스캐닝절차 > < 제안 OSG femtocell 의스캐닝절차 > Number of Femtocell BSs (CSG + OSG) < Scan duration : IEEE e 기존절차대비 73.4% 감소 > - 강신헌, 김재현, 강충구 " 펨토셀기지국탐색방법및이를이용한펨토셀통신시스템," 국내특허, 출원일 : 출원번호 :

16 L3 Mobility Management MIP (Mobile IP), FMIP (Fast Handovers for Mobile IP) HMIP (Hierarchical Mobile IP) PMIP (Proxy Mobile IP) PMIP 사전주소할당기법 MIH (Media Independent Handover) LISP (Locator/ID Separation Protocol) HIP (Host Identity Protocol) MOBIKE (IKEv2 Mobility and Multihoming Protocol) 15

17 L3 MIP / FMIP Mobile IPv4 (RFC 3344, RFC 4721) Mobile IPv6 (RFC 3775) Fast Handovers for Mobile IPv6 (RFC 4068) < MIP 의기본동작절차 > < FMIP 의기본동작절차 > MN: Mobile Node, FA: Foreign Agent, HA: Home Agent, CN: Correspondent Node, PAR: Previous Access Router, NAR: Next Access Router 16

18 L3 HMIP Hierarchical Mobile IPv6 (RFC 5380) MAP (Mobile Anchor Point) 에서단말의이동에따른 binding update 관리 MN: Mobile Node, HA: Home Agent, CN: Correspondent Node, MAP: Mobile Anchor Point, AR: Access Router 17

19 L3 PMIP Proxy Mobile IPv6 (RFC 5213) 단말의개입없이망에서 Mobile IP 기능수행 IP Tunnel IP-in-IP tunnel between LMA and MAG LMA: Localized Mobility Agent MAG: Mobile Access Gateway MAG LMA Home Network MN s Home Network (Topological Anchor Point) movement MAG LMM (Localized Mobility Management) Domain LMA Address (LMAA) That will be the tunnel entry-point MN s Home Network Prefix (MN-HNP) CAFE:2:/64 MN Home Address (MN-HoA) MN continues to use it as long as it roams within a same domain Proxy Binding Update/Ack. (PBU/PBA) Control messages exchanged by MAG to LMA to establish a binding between MN-HoA and Proxy-CoA Proxy Care of Address (Proxy-CoA) The address of MAG That will be the tunnel end-point 18

20 L3 PMIP 사전주소할당기법 ( 아주대 ) 제안하는 PMIP 기술 HO interruption time 감소 (RED BOX) L2 HO 의수행이전에 L3 HO 의트리거 (1) Binding update 병렬처리 (2) L2 HO 완료후 Router Advertisement 전달 (3) Packet loss 감소 (GREEN BOX) (1) (1) (2) Serving MAG 를통한 L3 HO 정보전달 (1) Target MAG 결정후 Buffering & Tunneling 수행 (2) (2) L2 링크재설정후터널링된패킷의전송 (3) 추가고려사항 망토폴로지획득과정에서 MN 의 L3 HO 필요유무인지 L2 링크재설정실패에의한 roll back (3) Router Solicitation 정보의손실극복 (3) - 이현진, 김재현 " 패킷손실을감소시키기위한공격적인 PMIP 기술," in Proc. 한국통신학회동계학술대회, 용평, 2010 년 02 월. 19

21 L3 PMIP 사전주소할당기법 ( 아주대 ) 터널링및하위계층 trigger 유무에따른서비스품질변화분석 Trigger vs. No Trigger L2 HO 의완료이후 L3 HO 를 trigger 하는경우에비해핸드오버지연이평균 44msec 이감소하여 MOS 값이평균 증가 Tunnel vs. No Tunnel Voice traffic 터널링및사전 L3 HO 수행으로서비스단절시간이평균 98.7msec 감소 터널링에의해패킷손실은감소하나고정자원을할당하는 UGS 에의하여터널링된패킷의우선전송으로평균전송지연이증가하여 MOS 값은평균 증가 Basic PMIP(NO Trigger, No Tunnel) Basic PMIP with trigger(trigger, No Tunnel) Tunnelled PMIP with trigger (Trigger, Tunnel) Satisfied Some Users Dissatisfied sec) Total Signaling Delay(m MOS value Many Users Dissatisfied Nearly All Users Dissatisfied All Users Dissatisfied Basic PMIP(No Trigger, Tunnel) Basic PMIP with Trigger(Trigger, No Tunnel) Tunnelled PMIP(Trigger, Tunnel) Background Traffic Load(%) Background Traffic Load(%) - 이현진, 김재현 " 패킷손실을감소시키기위한공격적인 PMIP 기술," in Proc. 한국통신학회동계학술대회, 용평, 2010 년 02 월. 20

parameter, handover, transmission status, MIH command service Link

22 L3 MIH IEEE Media Independent Handover MIH event service State change, link parameter, handover, transmission status, MIH command service Link capability discover, link event subscription, parameter measurement, MIH information service Available networks, cost, QoS, system information, 21

23 L3 LISP Locator/ID Separation Protocol 기존에는인터페이스마다 IP주소가하나씩할당되므로멀티호밍시한사용자가여러개의주소를갖게되어사용자식별이어려움 기존 IP 헤더의송수신주소를각호스트의에지라우터주소로설정하고, ICMP 헤더에초기에할당받은 IP 주소 (EID) 를 encapsulation하여식별자로사용 < LISP 프로토콜구조 > < LISP 동작절차 > 22

24 L3 HIP Host Identity Protocol (RFC 4423) 현재의 IP 주소는 locator로만이용하고, 공개키기반의호스트식별자 HIT(Host Identity Tag) 를새롭게도입 하나의호스트가복수의식별자를생성할수있으며, 각각의인터페이스에다른식별자를할당하여멀티호밍지원가능 암호화된공개키는호스트인증에도이용가능 < HIP 헤더구조 > < HIP 프로토콜구조 > 23

L3 MOBIKE IKEv2 Mobility and Multihoming

25 L3 MOBIKE IKEv2 Mobility and Multihoming Protocol (RFC 4555) 이동성과멀티호밍보장을위한 Internet Key Exchange (IKEv2) 확장버전 VPN 사용자의이동으로인한 IP 주소변경시에도세션유지가능 멀티호밍시트래픽송수신인터페이스변경가능 GPRS VPN client WLAN xdsl Internet Corporate VPN gateway Corporate intranet 24

26 L4 Mobility Management SCTP (Stream Control Transmission Protocol) msctp (mobile Stream Control Transmission Protocol) 25

27 L4 SCTP Stream Control Transmission Protocol (RFC 4960) UDP 와 TCP 의장점이조합된전송프로토콜 Feature Name UDP TCP SCTP Connection oriented X O O Reliable transport X O O Unreliable transport O X O Preserve message boundary O X O Ordered delivery X O O Unordered delivery O X O Data checksum O O O Checksum size (bits) Partial checksum X X X Path MTU X O O Congestion control X O O Multiple streams X X O Multi-homing i support X X O Multi-Homing 세션이여러개의 IP 주소를동시에사용할수있도록함 네트워크장애가발생하는경우대체경로 ( 대체 IP 주소 ) 를통해세션유지 Multi-Streaming 하나의세션을통해다양한종류의응용데이터를보낼수있게함 세션초기화단계에전송할스트림개수를통보 데이터복구및재전송과정은스트림 ID 별로수행됨 Bundling / Nagle X O O 26

28 L4 msctp mobile Stream Control Transmission Protocol 이동단말의이동에의해 IP 주소가변경되는경우동적으로 IP 주소를추가 / 삭제함으로써세션유지가능 - M. Riegel and M. Tuexen, Mobile SCTP, IETF Internet-Draft, draft-riegel-tuexen-mobile-sctp-09.txt, Nov

29 L5 Mobility Management User-centric terminal-controlled mobility 28

30 L5 User-centric Mobility ( 아주대 ) User-centric terminal-controlled (network-assisted) seamless mobility 29

31 L5 User-centric Mobility ( 아주대 ) Service continuity management 멀티호밍을이용하여하나의서비스를다중경로를통해전송 Server1 Server2 Server3 Server4 Segment request Service traffic transmission IP backbone Service discovery request Service discovery server RAN1 RAN2 RAN3 Service discovery response Service1 Terminal Segment1 Segment2 Segment3 Segment4 Server1 Server2 Server3 Server4 Service1 30

32 L5 User-centric Mobility ( 아주대 ) Information UI (User Interface) Management 사용자사용자선호도정보설정정보관리 RAT별선호도, 가중치 서비스플로우정보관리 SCM (Service Continuity Management) 서비스종류, 전송프로토콜, IP 주소등 이동중에도끊김없는서비스제공을위하여요구되는기능수행 QoE Management 다중서비스플로우결합 서비스별 QoE 파라미터생성 / 전달 서비스플로우별 QoE 모니터링 TJM (Traffic Junction Management) Sequence Management 동일 RAT에서전달된플로우의결합 다중서비스플로우결합다양한 RAT와 SCM간의연동을위한정보제공 Session Management 세션설정및관리

L5 User-centric Mobility ( 아주대 ) 다중경로선택기법 멀티호밍을통한핸드오버시최적경로선택알고리즘연구

15 1.05 Single path Diversity mode Audio (VBR) Video, interactive

mean < Effective data rate by service type > s i 1 p 1 p l 1 e e 1

1 PER of each path < 다중경로전송으로재전송최대 10% 감소 > < Multi-path selection

33 L5 User-centric Mobility ( 아주대 ) 다중경로선택기법 멀티호밍을통한핸드오버시최적경로선택알고리즘연구 ERi g si 1 L g Service Type Audio (CBR) g R peak si S i Single path Diversity mode Audio (VBR) Video, interactive R peak g Rpeak g 1 D Rpeak Rmean B i g R games, telnet 1 Web, FTP mean < Effective data rate by service type > s i 1 p 1 p l 1 e e PER of each path < 다중경로전송으로재전송최대 10% 감소 > < Multi-path selection algorithm > 32 < 사용자선호도에따른경로별 data rate 할당 > - S. H. Kang and J. H. Kim, "QoS-aware path selection for multi-homed mobile terminals in heterogeneous wireless networks," in Proc. CCNC 2010, Las Vegas, USA, Jan

34 그룹이동성관리기술 NEMO (Network Mobility) SIP based NEMO 협력스캐닝기법 사전인증기법 33

35 Group MM NEMO Network Mobility (RFC 3963) 버스, 기차등다수의단말이동시에이동하는경우모바일라우터를이용하여효율적인이동성관리가능 34

36 Group MM SIP based NEMO ( 아주대 ) SIP 기반의효율적인 group HO Network Mobility Server(NMS: 일종의 MR) 통신두절시, 사전 IP 주소할당 / 생성에따른 HO delay 감소 UA의접속시도대상별 (Access Router, Parent NMS 등 ) HO 절차제안 < AR 의주소정보사전할당에따른제안하는 HO 절차 > < 기존 SIP-NEMO 의 HO 절차 > < SIP protocol format 수정에따른제안하는 HO 절차 > - 안두성, 이현진, 김재현 "SIP 기반 NEMO 에서효율적인 Service Interruption 관리방안," in Proc. 한국통신학회하계학술대회, 제주도, 2010 년 6 월. 35

37 Group MM 협력스캐닝 ( 아주대 ) 500 Moving network 의협력스캐닝기법 동일한이동패턴을가진 Moving RS(MR) 와 MN이동일한시간에스캐닝을수행 연속된스캐닝에의한서비스단절시간감소 MR과 MN이스캐닝할인접기지국을나누어서수행하며결과의공유 스캐닝오버헤드감소 scanning de elay Total Conventional Scanning Mechanism Cooperative Scanning Mechanism Number of neighbor station < 기존기술은인접기지국의증가에따라스캐닝지연이선형으로증가하나협업을통한스캐닝은계단으로증가, 인접기지국의수가증가할수록유리 > Synchronous scanning - H. J. Lee and J. H. Kim, "A Cooperative Scanning Mechanism for the Mobile Relay in the Moving Network Environment," in Proc. CCNC 2010, Las Vegas, USA, Jan 이현진, 김재현 " 무선통신시스템의이동릴레이셀선택장치및방법," 국제특허 (PCT), 출원일 : 출원번호 : PCT/KR2009/

38 Group MM 사전인증기법 ( 아주대 ) 사전인증및 CID mapping 기법 Serving BS는핸드오버수행전에미리MS의인증정보및target BS 의인증정보교환 MS의인증을통한보안상의취약점극복 Scenario MS 별 HO 그룹 HO 사전인증 IEEE j CID mapping를통하여 moving network에있어도 MS의핸드오버참여감소 Network re-entry 과정에서 reauthentication에따른 handover interruption time 증가문제극복 Handover interruption time (msec) Mean th percentile Mean th percentile Mean th percentile Mean th percentile 이현진, 김재현 "IEEE j 망에서 MRS 의사전인증기반그룹핸드오버방안," in Proc. JCCI 2010, 안면도, 2010 년 04 월. 37

39 Thank you! Q & A 38

40 참고문헌 ITU-T Recommendation Q.1706/Y.2801, Mobility management requirements for NGN J. S. Kim and J. H. Kim, "Handover Scheme using Uplink and Downlink Channel Information in IEEE e Systmes," in Proc. VTC 2010-spring, Taipei, Taiwan, May H. J. Lee and J. H. Kim, "A Handover Time Negotiation for Seamless Service in IEEE E, " in Proc. MILCOM 2008, San Diego, USA, Nov 강신헌, 김재현, 강충구 " 펨토셀기지국탐색방법및이를이용한펨토셀통신시스템," 국내특허, 출원일 : 출원번호 : IETF RFC 3344, IP Mobility Support for IPv4 IETF RFC 4721, Mobile IPv4 Challenge/Response Extensions (Revised) IETF RFC 3775, Mobility Support in IPv6 IETF RFC 4068, Fast Handovers for Mobile IPv6 IETF RFC 5380, Hierarchical Mobile IPv6 (HMIPv6) Mobility Management IETF RFC 5213, Proxy Mobile IPv6 이현진, 김재현 " 패킷손실을감소시키기위한공격적인 PMIP 기술," in Proc. 한국통신학회동계학술대회, 용평, 2010년 02월. IETF RFC 4423, Host Identity Protocol IETF RFC 4555, IKEv2 Mobility and Multihoming Protocol IETF RFC 4960, Stream Control Transmission Protocol M. Riegel and M. Tuexen, Mobile SCTP, IETF Internet-Draft, draft-riegel-tuexen-mobile-sctp-09.txt, Nov S. H. Kang and J. H. Kim, "QoS-aware path selection for multi-homed mobile terminals in heterogeneous wireless networks," in Proc. CCNC 2010, Las Vegas, USA, Jan IETF RFC 3963, Network Mobility (NEMO) Basic Support Protocol 안두성, 이현진, 김재현 "SIP 기반 NEMO에서효율적인 Service Interruption 관리방안," in Proc. 한국통신학회하계학술대회, 제주도, 2010년 6월. H. J. Lee and J. H. Kim, "A Cooperative Scanning Mechanism for the Mobile Relay in the Moving Network Environment," in Proc. CCNC 2010, Las Vegas, USA, Jan 이현진, 김재현 " 무선통신시스템의이동릴레이셀선택장치및방법," 국제특허 (PCT), 출원일 : 출원번호 : PCT/KR2009/00672 이현진, 김재현 "IEEE j 망에서 MRS의사전인증기반그룹핸드오버방안," in Proc. JCCI 2010, 안면도, 2010년 04월. 39

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°í¼®ÁÖ Ãâ·Â Performance Optimization of SCTP in Wireless Internet Environments The existing works on Stream Control Transmission Protocol (SCTP) was focused on the fixed network environment. However, the number of