Ad hoc ????? IPv6 ?? ??

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Ad hoc ????? IPv6 ?? ?? Powered By Docstoc
					Ad hoc 환경에서의 IPv6 적용 기술

            정재훈
          PEC, ETRI
        paul@etri.re.kr




                          1
    Contents

   Introduction
   Ad-hoc Routing Protocols
   Autoconfiguration Technology for IPv6 MANET
   Global Connectivity for IPv6 MANET
   Conclusion




                                                  2
    Introduction (1/2)

   Categories of Wireless Networks
       Infrastructured Networks
            Cellular Networks, Wireless LAN (WLAN)
       Infrastructureless Networks
            Ad-hoc Networks


   Ad-hoc Networks
       유선 기반 망 (Infrastrured Networks) 없이 무선 이동단말로만 구
        성된 망
       Multi-hop Routing을 위해 각 이동단말이 Router 역할을 수행함
       용도
            긴급구조, 전쟁, 홈 네트워크, Shopping Mall, 임시 공동작업,
             도로에서의 차량 간의 통신, 공항에서의 티켓팅, 사무실 등.



                                                         3
 Infrastructured N/W vs. Infrastructureless N/W

                         Internet

     WLAN

                           Cellular




Mobile Ad-hoc Networks
                                           4
    Introduction (2/2)

   MANET에서의 이슈
       Ad-hoc Unicast Routing
       Ad-hoc Multicast/Broadcast Routing
       Power Saving
       Automatic Support of Networking Facility in MANET
            Autoconfiguration Technology
       Global Connectivity for MANET




                                                            5
        Ad-hoc Routing Protocols

 Ad-hoc Unicast Routing Protocols
 IPv6 Ad-hoc Routing Protocols

     IPv6 AODV
     IPv6 MAODV




                                     6
Ad-hoc Unicast Routing Protocols


              Ad-hoc routing protocols


                                  Source-initiated
    Table-driven
                                  Demand-driven




 DSDV         WRP        AODV       DSR         LMR    ABR


 CGSR                                           TORA   SSR




                                                             7
    Table-driven Routing Protocols

   Characteristics
       Maintenance of consistent, up-to-date routing information
        from each node to every other node in the network
       Each node
            maintains one or more tables to store routing information
            propagates updates of network topology


   Criterion of Classification of Routing Protocols
       Number of necessary routing-related tables
       Methods by which changes in network structure are broadcast


   Examples
       DSDV, CGSR, WRP, TBRPF, OLSR


                                                                         8
         Demand-driven Routing Protocols

   Characteristics
        Creation of routes only when desired by the source node
              By Route Discovery Process
        Route Discovery Process is completed
              Once a route is found
              When all possible route permutations have been examined
        Maintenance of a Route
              Until the destination becomes inaccessible along every path
               from the source
              Until the route is no longer desired

   Criterion of Classification of Routing Protocols
        Method by which route finding is performed

   Examples
        AODV, DSR, LMR, TORA, ABR, SSR
                                                                             9
    IPv6 Ad-hoc Routing Protocols

   IPv6 Ad-hoc Unicast Routing Protocol
       AODV (Ad-hoc On-demand Distance Vector) Routing Protocol
            AODVv6 which is IPv6 AODV has been being implemented by
             ETRI & ICU.
       AODV has been already implemented by some organizations
        including NIST.
            Linux Kernel Version: 2.4


   IPv6 Ad-hoc Multicast Routing Protocol
       MAODV (Multicast AODV) Routing Protocol
            MAODV works very similarly to PIM-DM.
            MAODVv6 which is IPv6 MAODV has been being implemented by
             ETRI & ICU.



                                                                       10
        AODV (1/3)

   AODV is improved DSDV algorithm
       AODV minimizes the number of required broadcasts by
        creating routes on a demand basis.

       AODV doesn’t maintain a complete list of routes as in
        DSDV algorithm.
          Nodes that are not on a selected path don’t maintain

           routing information or participate in routing table
           exchanges




                                                             11
    AODV (2/3)

   Path Discovery process
       When source node doesn’t already have a valid route to that
        destination, it initiates a path discovery process to locate the
        other node.
       Path Discovery
          broadcasts a route request (RREQ) packet to its neighbors.

          Neighbors forward the request to their neighbors, and so on

           until either the destination or an intermediate node
           with a “fresh enough” route to the destination is located.

   Loop-free
       AODV utilizes destination sequence numbers to ensure all
        routes are loop-free



                                                                     12
      AODV (3/3)

a) Propagation of the RREQ




b) Path of the RREP to the source




                                    13
    Autoconfiguration Technology
          for IPv6 MANET

 Autoconfiguration Technology?
 Autoconfiguration Technology for IPv6 MANET

     Unicast Address Autoconfiguration
     Multicast Address Autoconfiguration

     Multicast Name Resolution

     Service Discovery




                                                14
        Autoconfiguration Technology?
   What is Autoconfiguration?
       The technology that let IP-enabled devices be able to
        communicate one another in infrastructureless environment.

   Why is Autoconfiguration needed?
       To provide hosts with the automatic configuration related to
        networking.
       To let it possible for hosts communicate when either dynamic or
        static configuration is impossible.
       To provide the quick and easy configuration related to the network
        facility in MANET environment.|

   Issues of IETF Zeroconf Working Group
       Unicast Address Autoconfiguration
       Multicast Address Allocation
       Name Resolution (DNS)
       Service Discovery
                                                                       15
     Autoconfiguration Technology for IPv6 MANET

   Unicast Address Autoconfiguration
      Automatic configuration of a unique IP address within the scope in

        which the address will be used.

   Multicast Address Autoconfiguration
      Allocation of a unique multicast address for the application which

       needs a new multicast address.

   Multicast Name Resolution                                       Unicast Address Autoconfiguration

      Translation between name and




                                                                                                 Multicast Name Resolution
                                                Service Discovery
        IPv6 address
                                                                      Autoconfiguration
   Service Discovery                                                    Technology
      Discovery of the necessary service
                                                                    in IPv6-based MANET
       on the network without prior
       configuration.
                                                Multicast Address Autoconfiguration




                                                                                                                             16
          Autoconfiguration for IPv6 MANET

   Network Configuration                 Protocol Stack of Mobile Node

                                                            Application
                                           Multicast Name     Ad-hoc           Ad-hoc
                                            Resolution    Unicast Routing Multicast Routing

           B   C   D
      A                     E                                TCP / UDP


                                                                 IPv6

                       Mobile Node            Unicast Address           Multicast Address
                                             Autoconfiguration          Autoconfiguration
                       Wireless Link
                                                                 NIC




                                                                                      17
             Unicast Address Autoconfiguration (1/2)
             : Extended DAD Procedure in MANET
1st Try of Host A                                        MAC & IPv6 Address of Host C
 MAC Address - a9:bb:cc:dd:ee:ff                         MAC Address – a9:bb:cc:dd:ee:ff
 IPv6 Address - fec0:0:0:ffff:abbb:ccff:fedd:eeff        IPv6 Address - fec0:0:0:ffff:abbb:ccff:fedd:eeff

              MANET Prefix        EUI-64
      The address of Host A conflicts with that of Host C.
       Host C sends NA message to Host A.
2nd Try of Host A
 64-bit Random Number – 1111:2222:3333:4444
 IPv6 Address - fec0:0:0:ffff:1111:2222:3333:4444

                              Random Number
      The address of Host A doesn’t conflict with that of any other host.     Host C
       This address can be used as the unicast address of Host A.

                Host A                                 Host B
                          NS message                                                     NA message
                                                                                        Router


                                       Wireless Link
                              Where NS : Neighbor Solicitation,
                                    NA : Neighbor Advertisement

                                                                                                     18
 Unicast Address Autoconfiguration (2/2)
 : Procedure of Unicast Address Configuration

       Generation of Lower 64 bits in EUI-64


     Generation of Temporary address with
                                                     MANET_INIT_PREFIX
     MANET_INIT_PREFIX and Lower 64 bits
                                                          fec0:0:0:fffe::/64
     Generation of Tentative address with
      MANET_PREFIX and Lower 64 bits                 MANET_PREFIX
                                                         fec0:0:0:ffff::/64
     Transmission of Extended NS message



               Was any extended
              NA message received
                from other node?
 YES                                       NO

Generation of 64-bit           Configuration of
 Random Number              Unicast address in NIC



                                                                                19
                  Multicast Address Autoconfiguration

     Format of Site-local Unicast Address (a) and                     Procedure of Multicast Address
      Format of Site-local Multicast Address (b)                        Allocation

               48-bit           16-bit            64-bit                            Request of
                                                                            Multicast Address Allocation
(a)                         Subnet
         Network Prefix                         Interface ID
                              ID

        8 4,
           4     16                      64                    32         Generation of Unused Group ID

(b)            Subnet
        ff                       Interface ID           Group ID
                 ID
                                                                         Generation of a multicast address
         Flags          Scope                              Random
        P=1, T=1          5                                Number

                                                                         Delivery of the multicast address




                                                                                                           20
          Service of Multicast Application

                        B   C   D
               A                    E                  Multicast Service Scenario
                                                        1. Unicast Address Autoconfiguration
 Unicast Address                                          - Booting of each Mobile Node (MN)
Autoconfiguration                                         - Unicast address configuration in NIC
                                                        2. Multicast Address Autoconfiguration
      A                 B   C   D           E             - Run of Video-conferencing Tool
                                                          & Creation of a new Session
           1                1   1   1           1
                                                          - Allocation of a multicast address
           2        3                                   3. Advertisement of Sesstion information
                                                        4. Join to the new Session in MN A
           4        6
                                                        5. Join to the new Session in MN E
                                                5       6. Transmission of Video/Audio data
                                                           by MN A
                                        7               7. Transmission of Video/Audio data
                                                           by MN E

Multicast Address
Autoconfiguration
                                                                                                   21
Multicast Name Resolution
Multicast Name Resolution (MNR) is performed by
mDNS (Multicast DNS)

             Procedure of the resolution
              from domain name to IPv6 address in MNR
    Sender                                                                 Responder



          1       MNR query (What is IPv6 address of “host.private.local.”?)
                             via site-local multicast over UDP

              2     MNR response (IPv6 address of “host.private.local.”)
                                 via unicast over UDP


                  3 Verification of MNR response
                    - Does the value of the response conform to
                      the addressing requirements?

                  4 If the result is valid,
                      then the Sender caches and uses the response.
                      else the Sender ignores the response and continues
                          to wait for other responses.


                                                                                       22
     Service Discovery
     Service Discovery can be performed by MNR &
     DNS SRV Resource Record
    Simple Zone File containing DNS SRV resource records
     for service discovery
      $TTL 3600

      ;; Name to Address Lookups

      localhost.private.local. IN AAAA ::1
      ; Localhost with Loopback Address
      host.private.local. IN AAAA fec0:0:0:ffff::202:2dff:fe1b:e851
      ; MN’s Domain Name with Site-Local Address


      ;; DNS SRV Resource Records

      _multimedia1._tcp.private.local. 4000 IN SRV 0 1 3000 host.private.local.
      _multimedia2._udp.private.local. 4000 IN SRV 0 1 3001 host.private.local.




_service-name._protocol.domain-name TTL Class SRV Priority Weight Port Target



                                                                                  23
Global Connectivity for IPv6 MANET

 Internet Connectivity for IPv6 MANET
 Internet Gateway Discovery

 Network Mobility (NEMO)




                                         24
    Internet Connectivity for IPv6 MANET

   Why do we need to support the Internet
    connectivity in MANET?
       When mobile nodes in MANET want to communicate
        with hosts in the global Internet
       IETF NEMO BoF has started to study the support the
        network mobility.

   What is needed to support the global
    connectivity?
       Internet Gateway Discovery
            It informs the mobile nodes of the address of the gateway
             that connects MANET to the Internet.



                                                                    25
    Internet Gateway Discovery (1/2)

   Two ways to do Internet Gateway Discovery
       Extended Route Discovery
            Sending RREQ (Route Request) for global prefix information &
             Getting RREP (Route Reply)
            We need to extend RREQ / RREP of IPv6 AODV.
       Extended NDP (Neighbor Discovery Protocol)
            Sending MANET Route Solicitation (RS) &
             Getting MANET Router Advertisement (RA)
            We need to extend NDP.


   A node uses an arbitrary address for the discovery
       Home Address
       Site-local address by Unicast Address Autoconfiguration



                                                                            26
Internet Gateway Discovery
by Extended Route Discovery

             Internet


                    GW                     MANET
            RREQ             RREP

                      B             RREQ
     RREQ

              RREP
       A     Routing Table
              default: GW
                                      C

                                                   27
Internet Gateway Discovery
by Extended NDP

            Internet


                    GW                     MANET
            RS                RA

                     B                RS
      RS

               RA
       A    Routing Table
             default: GW
                                       C
             Global Unicast Address
               Autoconfiguration
                                                   28
    Network Mobility (NEMO)

   We need to support the Network Mobility
       정의: 단말 간의 통신과 인터넷으로의 연동 지원
       응용 분야
           PAN (Personal Area Network)
                 개인 휴대기기 이동망
           Public Safety System
                 재해복구 임시망
           Vehicular Network
                 항공기, 버스, 자동차, 지하철 망 등.


   What is MONET?
       정의: MONET(Mobile Network)는 인터넷 연동을 위해
        이동 라우터 (Mobile Router)를 포함한 하나 이상의 서브넷으로
        구성된 망.
       IETF NEMO BoF에서 연구되고 있음.


                                               29
NEMO Network


              Internet


WLAN


                         Cellular




        PAN


                                    30
     Internet Car
   약 70개의 정보단말이 내장
   3개의 서브넷으로 구성
        Multimedia network
             Car audio, Navigation system, etc.
        Body network
             Head light, Power window, etc.
        Control network
             Engine, Break, etc.
   Multi-homing 제공
        외부망과의 연동을 제공하기 위해 하나 이상의 Communication Device를 포함함.
           Cellular phone, WLAN, DSRC, PHS, etc.



                                                                         Mobile Routers

                            Cellular          WLAN           ITS
                             Phone


         Key     PDA    Speaker    Navigation        Audio         GW
                                                                    Body network

                                                                   GW
                                                                    Control network
                                                                                          31
    Conclusion
   Ad-hoc에서의 라우팅, 서비스, 인터넷 연동에 있
    어서 IPv6는 IPv4 보다 유리함.
       주소 자동 설정, 멀티캐스트 주소 할당, DNS 서비스, 서
        비스 탐색 등.
       Mobile IPv6를 이용한 네트워크 이동성 제공

       IPv6로 누구나 쉽게 시간과 장소에 관계없이 통신 서비
        스를 제공 받을 수 있음.

   Ad-hoc에서의 보안
       유선망과 WLAN 같은 무선망보다 네트워크 보안 제공
        이 어렵다.
           라우팅, 서비스 등의 Security 기능이 다른 네트워크 보다 더욱
            필요함.
                                               32
      References
[1] Elizabeth M. Royer and Chai-Keong Toh, “A Review of Current Routing Protocols for Ad Hoc Mobile
     Wireless Networks”, IEEE Personal Communications, April 1999.
[2] Charles E. Perkins, Elizabeth M. Belding-Royer and Samir R. Das, “Ad hoc On-Demand Distance Vector
     (AODV) Routing”, (work in progress) draft-ietf-manet-aodv-10.txt, January 2002.
[3] Elizabeth M. Royer and Charles E. Perkins, “Multicast Ad hoc On-Demand Distance Vector (MAODV)
     Routing”, draft-ietf-manet-maodv-00.txt, July 2000.
[4] Erik Guttman, "Autoconfiguration for IP Networking:Enabling Local Communication", IEEE Internet
     Computing, May/June 2001.
[5] Jaehoon Jeong and Jungsoo Park, “Autoconfiguration Technologies for IPv6 Multicast Service in Mobile Ad-
     hoc Networks”, 10th IEEE International Conference on Networks, Aug. 2002.
[6] Jung-Soo Park and Myung-Ki Shin, “Link Scoped IPv6 Multicast Addresses”, (work in progress) draft-ietf-
     ipv6-link-scoped-mcast-02.txt, July 2002.
[7] Levon Esibov, Bernard Aboba and Dave Thaler, “Linklocal Multicast Name Resolution (LLMNR)”, draft-
     ietf-dnsext-mdns-11.txt, July 2002.
[8] A. Gulbrandsen, P. Vixie and L. Esibov, “A DNS RR for specifying the location of services (DNS SRV)”,
     RFC2782, Feb. 2000.
[9] Ryuji Wakikawa, et al., “Global connectivity for IPv6 Mobile Ad Hoc Networks”, draft-wakikawa-manet-
     globalv6-01.txt, July 2002.
[10] Thierry Ernst and Hong-Yon Lach, “Network Mobility Support Terminology”, draft-ernst-monet-
     terminology-01.txt, July 2002.




                                                                                                     33

				
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