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Ad Hoc 라우팅 표준 (RFC3561) 과 IPv6 적용기법

Ad Hoc 라우팅 표준 (RFC3561) 과 IPv6 적용기법. 정재훈 (Jaehoon Paul Jeong) 한국전자통신연구원 표준연구센터 paul@etri.re.kr http://www.adhoc.6ants.net/ 2003. 10. 23. Contents. Introduction Ad Hoc Unicast Routing Protocols Demand-driven Routing Protocols AODV (RFC 3561) AODV Message Formats IPv6 AODV

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Ad Hoc 라우팅 표준 (RFC3561) 과 IPv6 적용기법

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  1. Ad Hoc 라우팅 표준(RFC3561)과 IPv6 적용기법 정재훈 (Jaehoon Paul Jeong) 한국전자통신연구원 표준연구센터 paul@etri.re.kr http://www.adhoc.6ants.net/ 2003. 10. 23 제1회 IPv6 표준화워크샵 및 표준설명회

  2. Contents • Introduction • Ad Hoc Unicast Routing Protocols • Demand-driven Routing Protocols • AODV (RFC 3561) • AODV Message Formats • IPv6 AODV • Autoconfiguration Technologies for IPv6 MANET • Summary • References 제1회 IPv6 표준화워크샵 및 표준설명회

  3. Introduction (1/2) • Categories of Wireless Networks • Infrastructured Network • Cellular Network, Wireless LAN (WLAN) • Infrastructureless Network • Ad Hoc Network • Ad Hoc Network • Temporary network composed of mobile nodes without preexisting communication infrastructure, such as Access Point (AP) and Base Station (BS). • Each node plays the role of router for multi-hop routing. • Application • War-field communication, Emergency recovery, Home-networking, Video-conferencing etc. 제1회 IPv6 표준화워크샵 및 표준설명회

  4. Internet WLAN Cellular Mobile Ad Hoc Networks Mobile Ad Hoc Networks 제1회 IPv6 표준화워크샵 및 표준설명회

  5. Introduction (2/2) • Issues in MANET • Ad Hoc Unicast Routing • Ad Hoc Multicast/Broadcast Routing • Power Saving • Global Connectivity for MANET • Addressing & DNS • Automatic Support of Networking Facility in MANET • Autoconfiguration Technology 제1회 IPv6 표준화워크샵 및 표준설명회

  6. Demand-driven(Reactive) Hybrid AODV DSR LMR ABR ZRP TORA SSR Ad Hoc Unicast Routing Protocols Ad Hoc routing protocols Table-driven(Proactive) DSDV OLSR TBRPF CGSR 제1회 IPv6 표준화워크샵 및 표준설명회

  7. 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 제1회 IPv6 표준화워크샵 및 표준설명회

  8. AODV (RFC 3561)Ad hoc On-Demand Distance Vector C. Perkins, E. Belding-Royer and S. Das, July 2003. 제1회 IPv6 표준화워크샵 및 표준설명회

  9. Contents • Overview of AODV • Route Discovery • Route Maintenance • Optimizations • AODV Message Formats 제1회 IPv6 표준화워크샵 및 표준설명회

  10. Overview of AODV (1/2) • AODV is improved DSDV algorithm • Reactive or On-demand • Provides unicast and multicast communication (MAODV) • 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. • Loop-free • AODV utilizes destination sequence numbers to ensure all routes are loop-free. 제1회 IPv6 표준화워크샵 및 표준설명회

  11. Overview of AODV (2/2) • Route Discovery process • When does it happen? • When source node doesn’t already havea valid route to a destination • Route Discovery • It 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. 제1회 IPv6 표준화워크샵 및 표준설명회

  12. B S A C D Route Discovery (1/10) 1. Node S needs a route to D in order to send data packets to D 제1회 IPv6 표준화워크샵 및 표준설명회

  13. B S A C D Route Discovery (2/10) 1. Node S needs a route to D in order to send data packet to D 2. Creates a Route Request (RREQ) Enters D’s IP addr, seq#, S’s IP addr, seq# hopcount (=0) 제1회 IPv6 표준화워크샵 및 표준설명회

  14. Route Discovery (3/10) B 2. Creates a Route Request (RREQ) Enters D’s IP addr, seq#, S’s IP addr, seq# hopcount (=0) 3. Node S broadcasts RREQ to neighbors RREQ S A C D 제1회 IPv6 표준화워크샵 및 표준설명회

  15. Route Discovery (4/10) B 4. Node A receives RREQ • Makes reverse route entry for Sdest = S, nexthop = S, hopcnt = 1 RREQ S A C D 제1회 IPv6 표준화워크샵 및 표준설명회

  16. Route Discovery (5/10) B 4. Node A receives RREQ • Makes reverse route entry for Sdest = S, nexthop = S, hopcnt = 1 • It has no route to D, so it rebroadcasts RREQ RREQ S A C D 제1회 IPv6 표준화워크샵 및 표준설명회

  17. Route Discovery (6/10) B 5. Node C receives RREQ • Makes reverse route entry for Sdest = S, nexthop = A, hopcnt = 2 • It has a route to D, and the seq# for route for D is >=D’s seq# in RREQ RREQ S A C D 제1회 IPv6 표준화워크샵 및 표준설명회

  18. Route Discovery (7/10) B 6. Node C sends RREP • C creates a Route Reply (RREP)Enters D’s IP addr, seq #S’s IP addr, hopcount to D (=1)Lifetime • Unicasts RREP towards A S A RREP C D 제1회 IPv6 표준화워크샵 및 표준설명회

  19. Route Discovery (8/10) B 7. Node A receives RREP • Makes forward route entry to Ddest = D, nexthop = C, hopcount = 2, Lifetime • Unicasts RREP to S RREP S A RREP C D 제1회 IPv6 표준화워크샵 및 표준설명회

  20. Route Discovery (9/10) B 8. Node S receives RREP • Makes forward route entry to Ddest = D, nexthop = C, hopcount = 3, Lifetime RREP S A C D 제1회 IPv6 표준화워크샵 및 표준설명회

  21. Route Discovery (10/10) B 9. Node S sends data packets on route to D S A C D 제1회 IPv6 표준화워크샵 및 표준설명회

  22. Route Maintenance (1/5) B 1. Link between C and D breaks down • C can perform local repair for the route to D S A RERR C D 제1회 IPv6 표준화워크샵 및 표준설명회

  23. Route Maintenance (2/5) B 1. Link between C and D breaks down • C can perform local repair for the route to D 2. Node C invalidates route to D in route table S A RERR C D 제1회 IPv6 표준화워크샵 및 표준설명회

  24. Route Maintenance (3/5) B 3. Node C creates Route Error (RERR) message • C creates a Route Error (RERR)Enters DestCount (=1), D’s IP addr, seq # • Lists all destinations which are now unreachable • “DestCount” field indicates the number of unreachable destinations included in the RERR message. • Sends to upstream neighbors in precursor list S A RERR C D 제1회 IPv6 표준화워크샵 및 표준설명회

  25. Route Maintenance (4/5) B 4. Node A receives RERR • Checks whether C is its next hop on route to D • Deletes route to D or invalidates the route to D according to N flag (No delete flag) • When N flag is set, A does not send RERR to S and may reinitiate route discovery for D. • Forwards RERR to S RERR S A RERR C D 제1회 IPv6 표준화워크샵 및 표준설명회

  26. B RERR S A C D Route Maintenance (5/5) 5. Node S receives RERR • Checks whether A is its next hop on route to D • Deletes route to D • Rediscovers route if still needed 제1회 IPv6 표준화워크샵 및 표준설명회

  27. Optimizations (1/2) • Expanding Ring Search • It prevents flooding of network during route discovery • Control Time To Live (TTL) of RREQ to search incrementally larger areas of network • Advantage • Less overhead when successful • Disadvantage • Longer delay if route not found immediately 제1회 IPv6 표준화워크샵 및 표준설명회

  28. Optimizations (2/2) • Local Repair • It repairs breaks in active routes locally instead of notifying source. • If the first repair attempt is unsuccessful, it sends RERR to source. • Advantage • Link repair with less overhead, delay and packet loss. • Disadvantage • Longer delay and greater packet loss when unsuccessful 제1회 IPv6 표준화워크샵 및 표준설명회

  29. AODV Message Formats 제1회 IPv6 표준화워크샵 및 표준설명회

  30. Route Request (RREQ)Message Format 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type |J|R|G|D|U| Reserved | Hop Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RREQ ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination IP Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Originator IP Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Originator Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 제1회 IPv6 표준화워크샵 및 표준설명회

  31. Route Reply (RREP)Message Format 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type |R|A| Reserved | Prefix Sz | Hop Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination IP address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Originator IP Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 제1회 IPv6 표준화워크샵 및 표준설명회

  32. Route Error (RERR)Message Format 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type |N| Reserved | DestCount | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreachable Destination IP Address (1) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreachable Destination Sequence Number (1) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| | Additional Unreachable Destination IP Addresses (if needed) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Additional Unreachable Destination Sequence Numbers (if needed) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 제1회 IPv6 표준화워크샵 및 표준설명회

  33. Route Reply Acknowledgement (RREP-ACK) Message Format 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ • RREP-ACK message MUST be sent in response to a RREP message with the ‘A’ bit set. • This is typically done when there is danger of unidirectional links preventing the completion of a Route Discovery cycle. 제1회 IPv6 표준화워크샵 및 표준설명회

  34. IPv6 AODV C. Perkins, E. Belding-Royer and S. Das, draft-perkins-manet-aodv6-01, November 2001. 제1회 IPv6 표준화워크샵 및 표준설명회

  35. AODV for IPv6 Operation • Message Handling • The handling of IPv6 AODV for IPv6 AODV messages is analogous to IPv4 AODV. • AODV messages have the formats appropriate for use with 128-bit IPv6 addresses. • ICMP Processing • Whenever IPv4 AODV specifies use of ICMP, the operation for IPv6 uses ICMPv6. • Configuration Parameters • IPv4 and IPv6 AODVs use the same parameters. 제1회 IPv6 표준화워크샵 및 표준설명회

  36. Autoconfiguration Technologies for IPv6 MANET Reference Paper:http://www.adhoc.6ants.net/publications/international-conference/icoin2004-jaehoon.pdf 제1회 IPv6 표준화워크샵 및 표준설명회

  37. Autoconfiguration? • What is Autoconfiguration? • The technology that allows IP-enabled devices be able to communicate one another in infrastructureless environment. • Issues of IETF Zeroconf Working Group • Unicast Address Autoconfiguration • Multicast Address Allocation • Name Resolution (DNS) • Service Discovery • Why is Autoconfiguration needed in MANET? • To provide the quick and easy configuration related to the networking in MANET with dynamic topology. 제1회 IPv6 표준화워크샵 및 표준설명회

  38. Unicast Address Autoconfiguration AutoconfigurationTechnologyfor IPv6 MANET Service Discovery Multicast DNS Multicast Address Allocation Autoconfiguration Technology for IPv6 MANET • Unicast Address Autoconfiguration • Automatic configuration of a unique IPv6 address within MANET • Multicast Address Allocation • Allocation of a unique multicast address for the application which needs a new multicast address • Multicast DNS • Translation between name andIPv6 address • Service Discovery • Discovery of the necessary service 제1회 IPv6 표준화워크샵 및 표준설명회

  39. Summary • AODV • It is a Reactive/On-demand Ad Hoc routing protocol. • Route Discovery cycle • Sequence numbers are used for route freshness and loop prevention. • It maintains only active routes. • Optimizations can be used to reduce overhead and increase scalability. • IPv6 AODV • Autoconfiguration Technologies for IPv6 MANET 제1회 IPv6 표준화워크샵 및 표준설명회

  40. References [1] C. Perkins, E. Belding-Royer and S. Das, “Ad hoc On-Demand Distance Vector (AODV) Routing”, RFC 3561, July 2003. [2] C. Perkins, E. Belding-Royer and S. Das, “Ad Hoc On Demand Distance Vector (AODV) Routing for IP version 6”, draft-perkins-manet-aodv6-01, November 2001. [3] Auto-Networking Technologies for IPv6 MANET, http://www.adhoc.6ants.net/publications/international- conference/icoin2004-jaehoon.pdf [4] ETRI Ad Hoc Project, http://www.adhoc.6ants.net/ 제1회 IPv6 표준화워크샵 및 표준설명회

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