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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title : [ A Routing Algorithm for Efficient Real-Time Network Address Allocation Mechanisms Based on LAA Concept in a Mesh Network ] Date Submitted: [20 July , 200 6]
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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [A Routing Algorithm for Efficient Real-Time Network Address Allocation Mechanisms Based on LAA Concept in a Mesh Network] Date Submitted: [20 July, 2006] Source: [Ho-In Jeon (1) and Yeonsoo Kim (2)] Company: [Dept. Electronic Engineering, Kyung-Won University (KWU) (1), Advanced Technology Lab., KT (2)] Address: [San 65, Bok-Jung-Dong, Sung-Nam-Shi, Kyung-Gi-Do, Republic of Korea] Voice 1: [ +82-31-753-2533], Voice 2:[ +82-19-9101-1394] FAX: [+82-31-753-2532], E-Mail: [jeon1394@kornet.net] Re: [This work has been supported by Advanced Technology Lab., KT, Korea.] Abstract: [This document proposes a routing algorithm for efficient real-time network address allocation mechanisms based on LAA concept in a Mesh Network.] Purpose: [Technical Contributions on the IEEE 802.15.5 Standard] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
A Routing Algorithm for Efficient Real-Time Network Address Allocation MechanismsBased on LAA Concept in a Mesh Network Ho-In Jeon (1) and YeonsooKim (2) (1) Kyung-Won University, HNRC of IITA, Republic of Korea, and (2) Advanced Technology Lab., KT Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Contents • Introduction: A Scenario on an Intelligent Parking Lot • Issues of Mesh Networks • A Mesh Network Architecture • Beacon Scheduling Fundamentals with BOP Concept • Efficient Real-Time Short Address Allocations with LAA • Ad Hoc Routing Protocols • AODV Routing for the LAA Mechanism • Conclusion Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
A Scenario: An Intelligent Parking Lot U-Parking Lot Controller MEU Gatewaywith/without Gate Controller MEU Sensor Node Internet Wired Network MEU Router Wireless Mesh Assoc. relation Info. Transfer U-City Control and Management Center Basement 1 MEU Gateway Basement 2 Basement 3 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Mesh Networking Capabilities Mobility Support of the Devices Fast Association Dynamic Topology Fast Routing: Proactive and Reactive, and Hybrid Fast Device Discovery Fast Service Discovery QoS Support Low Power Consumptions The Scenario Requires… Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Multiple Beacons in One Superframe Beacon Scheduling for Beacon Collision Avoidance Beacon Aggregation for throughput enhancement in the case of two or more PANs are merging. Efficient Real-Time Short Address Allocation Algorithms Routing Algorithm: Proactive or Reactive Power-Efficient Operation Mode Support of Time-Critical or Delay-Sensitive Applications Resource Reservation for Data Transmission Hidden Node and Exposed Node Problems Issues of Mesh Networks Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Operating Principles of Mesh Networks • Devices are associated sequentially, one by one. • The relation between parent and children are characterized by association request and response. • My parent and children are my neighbors. • All devices I can hear are my neighbors. • When an association request is granted by multiple nodes, the new node decides to associate with the node which has lower depth. • When depth information is the same, he decides to associate with the node which transmits his beacon earlier than others. Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Beacon Scheduling - Fundamentals • Every node sends his beacon with beacon payload containing its depth information, its Beacon Transmission Time Slot (BTTS), and BTTS’s occupied by his neighbors and neighbor’s neighbors. • The first beacon slot can be used only by the PNC for the protection of PAN’s basic information. • Solid blue line represents the Parent-Child relations based on associations, while red line represents directly reachable. • Every mesh device shall transmit his beacon during the BOP (Beacon-Only Period) at the BTTS scheduled in a distributed manner. 2 1 PNC CAP BOP 3 1 1 3 2 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Beacon Payload Info. for Beacon Scheduling • When a node sends his beacon with beacon payload shown below, the receiver nodes can obtain the information of the BTTS occupied by its neighbors and its neighbor’s neighbors. • The beacon scheduling is performed by choosing the smallest time slot of the BOP slots which avoids the time slots occupied by neighbors and its neighbor’s neighbors. <Information contained in the beacon payload> Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Beacon Scheduling 14 16 17 12 18 13 11 15 19 2 5 9 20 1 6 PNC 8 10 4 3 7 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Beacon Scheduling 14 16 17 12 13 11 15 2 5 9 1 6 8 10 PNC 4 3 7 Deep Sleep BOP BOP CFP CAP 1 1 3 4 5 6 2 9 13 18 2 7 8 12 14 15 10 11 10 16 17 16 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Beacon Scheduling Performed! 4 14 2 6 16 3 17 12 18 11 13 7 10 11 3 6 15 19 2 5 2 9 10 5 9 1 20 1 2 6 6 4 8 10 PNC 4 3 7 8 3 7 Deep Sleep BOP BOP CFP CAP 1 1 3 4 5 6 2 9 13 18 2 7 8 12 14 15 10 11 10 16 17 16 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Short Address Allocations • Hierarchical Block addressing wastes address space. • Centralized Address allocations • May take too much time for the address allocation. • Distributed Address allocations • No guaranteed way of avoiding address conflicts. • A mechanism of assigning short addresses in real-time in an efficient way that can prevent address conflict has been needed. • Combination of the two mechanisms. • Beacon Scheduling mechanism can be used for the address allocation Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Adaptive Block Addressing [children#][children#]=[8][6] • Stage 1: Association resv’ed: [beg,end]=[0,9000]branch1: [beg,end]=[9001,41000]branch2: [beg,end]=[41001,65000] A • Stage 2: Children number collection [5][2] [5] B J [9001,13000][13001,33000][33001,41000] [41001,45000][45001,65000] • Stage 3: Address assignment • An adaptive tree (AT) is formed. • Additional addresses are reserved. [1][2][1] [3][1] C H K [1] [13001,17000][17001,21000][21001,29000][29001,33000] [45001,49000][49001,61000][61001,65000] [33001,37000][37001,41000] [0] [37001,41000] [0] D E G I L O [0] [1][1] [61001,65000] [1] [0] [29001,33000] [49001,53000][53001,57000][57001,61000] [17001,21000] [21001,25000][25001,29000] F M N [0] [0] [0] [25001,29000] [57001,61000] [53001,57000] Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Efficient Real-Time Address Assignment PNC A [0, 1] [1, 4] [1, 2] [1, 3] D C B • Devices B, C and D hear the beacon of A (PNC) and send Association Request Command. • Since A is PNC, PNC allocates the Short addresses to devices B,C,D directly. • If other device than PNC allocates shortAddress, it is possible that same address could be allocated to different devices. • To avoid this problem, LAA (Last Address Assigned) field has been added. • The last address assigned at this point is 4, and the PNC sends this information to other devices using his beacon payload. To let B, C, and C know about this. Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Efficient Real-Time Address Assignment PNC A Beacon Update Request Command Beacon Update Request Command [1, 2] [1, 4] D C B [1, 3] [2, 5] [2, 5] I E Overlapped address assigned in real-time • A possible problem • When E and I associate, respectively, with B and D simultaneously, the same address may be assigned to tow different devices. • Solution • When this happens, the PNC sends Address Reassignment Command to the later arriving device Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Efficient Real-Time Address Assignment PNC A Beacon Update Request Command Beacon Update Request Command Address Reassign D C B Beacon Update Request Command Beacon Update Request Command Beacon Update Request Command Beacon update Response command Address Reassign G H E F Beacon Update Request Command Beacon Update Request Command Beacon update Response command Beacon Update Request Command Address Reassign Address Reassign I J K Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Concerns about LAA-Based Addressing • Possible address conflicts when two nodes join the network at the same time. • Can be a fundamental limitation. But can be solved. • Long Delay for Resolving the Conflicts • Can be fundamental, but the only way to solve the problem. • Inefficiency for Tree Routing • Because it is not a structured addressing. • Is it inefficient to every routing algorithm? • Not Really!!! Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Ad Hoc Network • A collection of two or more devices equipped with wireless communications and networking capability (Infrastructure-less Infrastructure) • Every node can forward packets • Self-organizing, adaptive • IETF WG • MANET (Mobile Ad hoc Network) • http://www.ietf.org/html.charters/manet-charter.html Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Recommendations in Data-Link Layer • Avoid unnecessary retransmissions. • Avoid collisions. • Put receiver in standby mode whenever possible. • Use/allocate contiguous slots for transmission and reception whenever possible. • Turn radio off and go into sleep mode when not transmitting or receiving. Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Recommendations in Network Layer • Consider route relaying load. • Consider battery life in route selection. • Reduce frequency of sending control message. • Optimize size of control headers. • Efficient route reconfiguration techniques. Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Ad Hoc Routing Protocols AD-HOC MOBILE ROUTING PROTOCOLS TABLE DRIVEN/ PROACTIVE ON-DEMAND-DRIVEN/REACTIVE HYBRID Tree Routing DSDV WRP CGSR STAR DSR ABR TORA AODV CBRP RDMAR ZRP Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Routing Protocols • Proactive (Table-Driven) • DSDV (Destination Sequenced Distance vector) • WRP (Wireless Routing Protocol) • CSGR (Cluster Switch Gateway Routing) • Reactive (On-demand-driven) • AODV (Ad Hoc On-Demand Distance Vector Routing) • DSR (Dynamic Source Routing) – Use Cache • SSR (Signal Stability Routing) • PAR (Power-Aware Routing) • ABR (Associativity-Based Long Lived Routing) • Hybrid • ZRP (Zone Routing Protocol) Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
DSDV • Destination Sequenced Distance Vector • Charles E. Perkins • Proactive • Table-driven • Based on Bellman-Ford Routing Algorithm • Full Dump & Incremental Packet • Too many overheads for Ad Hoc Networks Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
AODV • Improvement on DSDV • Supports only bi-directional link • AODV allows mobile nodes to obtain routes quickly for new destinations and does not require nodes to maintain routes to destinations that are not in active communication. • Route Discovery • Uses Expanding Ring Search to limit the flood of routing packets • Reverse Paths are setup by Route Request (RREQ) packets broadcast from Source node • Forward Paths are setup by Route Reply packet (RREP) sent from destination node or any intermediate node with a valid route to the destination Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Features of AODV • Route Maintenance • Nodes monitor the link status of next hops in active routes. • When a link break in an active route is detected, a Route Error message is used to notify other nodes that the loss of that link has occurred. • Route Error message is a unicast message, resulting in quick notification of route failure. • Loop Freedom • All nodes in the network own and maintain its destination sequence number which guarantee the loop-freedom of all routes towards that node. • It avoids the Bellman-Ford "counting to infinity" problem by using sequence numbers. Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
RREQ Message Format 1 byte 1 byte 1 byte 1 byte 11 bits 1 byte 1 byte 1 1 bit 1 1 1 Type J R G D U Reserved Hop Count RREQ ID Destination IP Address Destination Sequence Number Originator IP Address Originator Sequence Number Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
RREP Message Format 1 byte 1 byte 1 byte 1 byte 5 bits 1 1 byte 1 9 bits 1 byte Type R A Reserved Prefix Size Hop Count Destination IP Address Destination Sequence Number Originator IP Address Lifetime Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
RERR Message Format 1 byte 1 byte 1 byte 1 byte 1 1 byte 1 byte 15 bits Type N Reserved Dest. Count Unreachable Destination IP Address (1) Unreachable Destination Sequence Number (1) Additional Unreachable Destination IP Addresses (if needed) Additional Unreachable Destination Sequence Numbers (if needed) Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
RREP Ack Message Format • Type = 4 • Reserved: Sent as 0 • Ignored on reception. 1 byte 1 byte Type Reserved Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Basic Routing Algorithm Is it a broadcast? Broadcast Frame YES Frame from higher layer NO Is it a broadcast? YES Frame from lower layer B A Is the destination my end-device Child? Route directly YES Is it for me? NO YES C Routing capacity? NO Send frame to higher layer E YES Routing entry for this destination? Discover route? NO NO Routing along the tree YES YES Route to next hop Initiate route discovery Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Receipt of Route Request Creates table entries NO Am I the destination? Existing route discovery table entry? Routing capacity? NO RREQ received YES YES YES Respond with RREP Am I the destination or is one of my end- Devices? Valid path? YES Discard RREQ NO Forward RREQ NO RREQ has lower Path cost than Tables? YES Am I the destination? Unicast RREQ NO RREQ has lower Path cost than Tables? Update tables and respond with RREP YES NO YES Reply with RREP NO Discard RREQ Discard RREQ Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Receipt of Route Reply Discard RREP NO NO Update Tables NO Path cost in RREP Less than cost in Tables? Table entries exists? RREP received Path cost in RREP Less than cost in Tables? YES YES YES Update path cost and forward RREP Routing capacity? Table entries exists? Am I the destination? YES YES YES Routing table entry Active? NO YES NO Am I the destination? Discard RREP NO YES Set entry Active, update tables Update tables and respond with RREP NO Update tables Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Criteria for AODV Routing Table • Choose the route with smaller Hop Count. • Select the route with larger RSSIor LQI when Hop Count is the same. • Determine the route toward its parent when Hop Count and RSSIvalue are the same. • Decide the route with smaller Network Address value when there are no parent-child relationships. • Discard the RREQ message when the received Hop Count is greater than hisHop Counter. Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
AODV Routing Example 14 16 Destination 17 12 18 13 11 15 19 2 5 9 20 MPC 1 6 8 10 Source 4 3 7 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
AODV RREQ Routing : Stage 1 14 16 Destination 17 12 18 13 11 RREQ Broadcast 15 19 2 5 9 20 MPC 1 6 8 10 Source 4 3 7 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
AODV RREQ Routing : Stage 2 14 16 Destination 17 12 18 13 11 15 RREQ Broadcast 19 2 5 9 20 MPC 1 6 8 10 4 Source 3 7 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
AODV RREQ Routing : Stage 3 14 16 Destination 17 12 18 13 11 RREQ Broadcast 15 19 2 5 9 20 MPC 1 6 8 10 Source 4 3 7 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Routing Tables with RREQ by Node 1 Node 1 RREQ #1 Update Information About Previous Hop DST NEXT HOP ORI DST HOP Update Information About Originator 1 18 0 Node 2 Node 3 Node 4 Node 9 Node 15 DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Routing Tables in the 2nd Stage Node 1 RREQ #2 Update Information About Previous Hop DST NEXT HOP ORI DST HOP Update Information About Originator 1 18 1 Node 2 Node 3 Node 4 Node 9 Node 15 DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Node 5 Node 6 Node 7 Node 11 Node 12 DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP 2 2 2 4 4 2 3 3 2 2 2 2 15 15 2 1 2 2 1 4 2 1 3 2 1 2 2 1 15 2 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Routing Tables in the 3rd Stage Node 1 RREQ #3 Update Information About Previous Hop DST NEXT HOP ORI DST HOP Update Information About Originator 1 18 2 Node 2 Node 3 Node 4 Node 9 Node 15 DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Node 5 Node 6 Node 7 Node 11 Node 12 DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP 2 2 2 4 4 2 3 3 2 2 2 2 15 15 2 1 2 2 1 4 2 1 3 2 1 2 2 1 15 2 Node 8 Node 13 Node 14 Node 17 Node 18 DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP 11 11 3 5 5 3 11 11 3 11 11 3 5 5 3 1 11 3 1 5 3 1 11 3 1 11 3 1 5 3 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Routing Tables in the 3rd Stage Node 1 RREQ #3 Update Information About Previous Hop DST NEXT HOP ORI DST HOP Update Information About Originator 1 18 2 Node 2 Node 3 Node 4 Node 9 Node 15 DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Node 5 Node 6 Node 7 Node 11 Node 12 DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP 2 2 2 4 4 2 3 3 2 2 2 2 15 15 2 1 2 2 1 4 2 1 3 2 1 2 2 1 15 2 Node 19 Node 20 Node 14 Node 17 Node 18 DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP 11 11 3 6 6 3 6 6 3 11 11 3 5 5 3 1 11 3 1 6 3 1 6 3 1 11 3 1 5 3 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
AODV RREP Routing : Stage 4 14 16 Destination 17 12 18 13 11 15 RREP Unicast 19 2 5 9 20 MPC 1 6 8 10 Source 4 3 7 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
AODV RREP Routing : Stage 5 14 16 Destination 17 12 18 13 11 15 RREP Unicast 19 2 5 9 20 MPC 1 6 8 10 Source 4 3 7 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
AODV RREP Routing : Stage 6 14 16 Destination 17 12 18 13 11 15 RREP Unicast 19 2 5 9 20 MPC 1 6 8 10 Source 4 3 7 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Routing Tables in the 4th Stage Update Information About Previous Hop Update Information About Originator RREP ORI DST HOP 1 18 0 Node 5 Node 18 DST NEXT HOP DST NEXT HOP 2 2 2 5 5 3 1 2 2 1 5 3 18 18 1 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Routing Tables in the 5th Stage Update Information About Previous Hop Update Information About Originator RREP RREP ORI DST HOP ORI DST HOP 1 18 1 1 18 0 Node 5 Node 18 Node 2 DST NEXT HOP DST NEXT HOP DST NEXT HOP 2 2 2 5 5 3 1 1 1 1 2 2 1 5 3 5 5 2 18 18 1 18 5 2 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Routing Tables in the 6th Stage Update Information About Previous Hop Update Information About Originator RREP RREP RREP ORI DST HOP ORI DST HOP ORI DST HOP 1 18 2 1 18 1 1 18 0 Node 5 Node 18 Node 2 Node 1 DST NEXT HOP DST NEXT HOP DST NEXT HOP DST NEXT HOP 2 2 2 5 5 3 1 1 1 2 2 3 1 2 2 1 5 3 5 5 2 18 2 3 18 18 1 18 5 2 Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Conclusions • Block addressing is good for tree routing, but wastes its memory space. • Stochastic addressing or sub-block addressing is considered. • Efficient real-time 16-bit network address allocation based on LAA concept • It can fully utilize the address space. • The address are assigned in real-time. • It may take long time to resolve the address conflicts, while it do not happen often. • Any addressing mechanism can be adopted for the routing protocol as long as AODV is used. • Showed that AODV algorithm for the LAA worked well. Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)
Acknowledgment • This work has been supported by Advanced Technology Lab. of KT. Ho-In Jeon (KWU) and Yeonsoo Kim (Advanced Technology Lab., KT)