1 / 58

VIRTUAL ROUTER

VIRTUAL ROUTER. Kien A. Hua Data Systems Lab School of EECS University of Central Florida. Outline. Mobile Ad Hoc Networks Virtual Router Approach Routing Data Forwarding Cooperation Enforcement in Virtual Router Approach Simulation Results Conclusions. Wireline Communications. D.

neil
Download Presentation

VIRTUAL ROUTER

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. VIRTUAL ROUTER Kien A. Hua Data Systems Lab School of EECS University of Central Florida

  2. Outline • Mobile Ad Hoc Networks • Virtual Router Approach • Routing • Data Forwarding • Cooperation Enforcement in Virtual Router Approach • Simulation Results • Conclusions

  3. Wireline Communications D Infrastructure Router Router Router Router Router S Routers help forward data packets

  4. What is Mobile Ad Hoc Network? All nodes participate in the routing and data forwarding process. Infrastructureless Source Node Destination Node

  5. Route Request Source Node Destination Node

  6. Route Reply Source Node Destination Node

  7. Data Transmission The selected nodes participate in the data forwarding process Source Node Destination Node

  8. Link Break Source Node Destination Node

  9. Issue Route Request Source Node Destination Node Selected New Route

  10. Handling High Mobility Using Physical Nodes as Routers: Mobility → link breaks → reroute → overhead ! D S • Using Virtual Routers: • Virtual routers are stationary • → links are robust • → fewer reroute • → less overhead ! Virtual Router D S

  11. What is a Virtual Router ? • A virtual router is a spatial area • Physical nodes within this area alternate in forwarding data • When a node leaves the area, it is no longer obliged to forward the data • Virtual router is stationary • More suitable for high mobility applications such as vehicular networks Y Virtual Router X D Z S

  12. Virtual Router – Example How to apply this concept to vehicular network ? Source Node Each node has GPS & grid map Each cell is a virtual router Destination Node

  13. Street Environment: Mobility Model • Streets constrain node mobility • Nodes can pause and change direction at intersections.

  14. Street Environment: Radio Range Buildings block radio signal • Often no link between nodes on different streets • Broadcast range is not a circle

  15. Virtual Routers in Street Environment • Streets are divided into small cells: • Each intersection is an intersection cell • A long road block can be divided into multiple block cells • Radio range must cover any 2 consecutive cells • Each cell is a virtual router

  16. Vehicular Network UsingVirtual Routers • “Green” virtual routers form a connecting path between source and destination • Data are transmitted from source to destination over these virtual routers Destination Source

  17. Location Discovery Similar to standard route request • A source node broadcasts a Location Discovery (LD) packet • This LD packet propagates until it reaches the destination node • When the LD packet arrives at the destination, it replies with a Location Reply (LR) packet that includes the location of the destination router (i.e., destination cell). Subsequently, every data packet carries the ID’s of the source and destination routers

  18. Data Forwarding: Reference Line Every data packet carries the locations of Source and Destination Reference line (RL) is the straight line connecting the center of the source router and the center of the destination router

  19. Data Forwarding: Reference Points Reference points(RP’s) are the intersections of the reference line and the streets

  20. Data Forwarding: Forwarding Zones • There is one forwarding zone for each reference point • Three horizontal and two vertical forwarding zones in this example • Some forwarding zones overlap • The forwarding zones make up the grid path for data forwarding

  21. Data Forwarding • Virtual routers within the forwarding zones are selected for data forwarding • When a node leaves the forwarding area, it is no longer obliged to forward data. • If a node enters the forwarding area, this node must participate in the data forwarding. How to do route maintenance

  22. Connection Maintenance Destination node moves away from current router • Reference line changes • Reference points changes • Forwarding zones changes • Need a new connection path Route Maintenance: • The destination node periodically updates its location with the source node. • If this fails, source issues a location discovery packet Essentially no overhead

  23. Selfish and Malicious Behavior It works as long as nodes cooperate Need cooperation enforcement !! Malicious Node

  24. Cooperation EnforcementStep 1: Detect Malicious Node Malicious behavior detected Malicious node Malicious behavior detected

  25. Cooperation EnforcementStep 2: Penalize Malicious Nodes No one will forward the Location Discovery packet for the malicious node. Malicious Node tries to establish connection by broadcasting Location Discovery packet I know about the misbehavior radio range of malicious node I know about the misbehavior I know about the misbehavior Location Discovery packet is blocked by the building Location Discovery packet is blocked by the building

  26. Network Layer Structure

  27. 3C Module

  28. 3C Module - Overview • It maintains three Counters: • Forward Request Counter: Number of forward requests (both discovery and data packets) received by a node. • Forward Counter: Number of packets forwarded by a node. • Location Discovery Counter: Number of Location Discovery packets initiated by a node (i.e., number of connections requested) • It adds a 3C header which contains the values of these three counters to every Location Discovery packet. • Based on this header, neighboring nodes analyze the behavior of the source node, and decide to forward or discard the packet (i.e., penalize the source node)

  29. Misbehavior Detection: Overview Examine 3C header for misbehavior Add 3C header Examine 3C header again before forwarding

  30. Route Discovery • Source node initiates Route Request packet • Intermediate nodes forward the packet until it reaches the Destination node • The Destination node receives the Route Request packet and sends back a Route Reply packet Request Request Request Request S D Reply Reply Reply Reply Let’s look at the operation at these nodes

  31. Initiate Location Discovery Upper Layer Submit a route request Routing Layer (Network) This is a reroute request Add to Session Table Yes No This is a new communication request MAC Layer (Data Link)

  32. Receive Location Discovery Routing Layer (Network) Penalize the requester Yes More on this module later… The forwarding node initiates this route request No No Yes No No Yes Yes Initiated by sender? MISBEHAVIOR DETECTION MODULE MAC Layer (Data Link)

  33. Forward Location Discovery (1) The Virtual Router has already forwarded the packet The route has been found No Yes No No Yes No Yes (Reply) Routing Layer (Network) Yes (Forward)

  34. Forward Location Discovery (2) Routing Layer (Network) Yes (Forward) Yes (Reply) MAC Layer (Data Link)

  35. Network Attack:Sending Dummy Packets Routing Layer (Network) Flood the network with a dummy record Generate & “forward” a dummy route request packet No MAC Layer (Data Link)

  36. Data Transmission • Source node transmits a data packet • Intermediate nodes forward the packet until it reaches the Destination node Data Data Data Data S D Let’s look at the data forwarding operation at a node

  37. Receive Data Packet Forwarding Procedure in VRA Routing Layer (Network) A node new to the virtual router might not know about this on-going session Yes No MAC Layer (Data Link)

  38. VRA Protocol Forwarding Procedure (Data Packet) These steps are the same as in Location Discovery packet No Yes No No The packet has reached its destination Yes Yes No Yes Routing Layer (Network)

  39. Forward Data Packet Routing Layer (Network) Yes Yes Packet arrives at destination MAC Layer (Data Link) Receive Data Packet

  40. Network Attack: Dummy Packets Routing Layer (Network) Flood the network with a dummy record Generate & “forward” a dummy data packet No MAC Layer (Data Link)

  41. Receive Location Discovery Routing Layer (Network) Yes We now discuss this module No No Yes No No Yes Yes MISBEHAVIOR DETECTION MODULE MAC Layer (Data Link)

  42. Misbehavior Detection Metrics 3C Module at each node i maintains the following information: • Forward Ratio (FR): Percentage of arriving packets forwarded • FRi = • Local Average Forward Ratio (LAFR) • LAFRi = , where, n is the number neighbor nodes of i • Request Ratio (RR): Offer enough service to use the network ? • RRi = • Forward Request Counter • Number of forward requests (both discovery and data packets) received by a node. • Forward Counter • Number of packets forwarded by a node. • Location Discovery Counter • Number of Location Discovery packets initiated by a node (i.e., number of connections requested)

  43. Initiate Misbehavior Detection Need to establish a communication connection with someone If m is not the source node, n proceeds to forward the packet else, n checks 3C header of this packet. Is the forwarder the initiator of this packet ? Location Discovery packet m n

  44. Misbehavior Detection: Check Forward Ratio FRm = FRn = FRm < FRn means that n is not forwarding enough packets FRm < FRn → n suspects m has been dropping packets m is a suspect Location Discovery packet m n

  45. Misbehavior Detection:Check Request Ratio RRm = RRn = RRm > 1.2*RRn → n suspects m has been dropping packets RRm > 1.2 ∙ RRn means that m made many connection requests; but it has not provided enough service to other nodes. n needs to exchange counter information with neighboring nodes m is a suspect Location Discovery packet m n

  46. Initiate Misbehavior Detection:Compare to Local Average k is the number of neighbor nodes of n LAFRn = x FRm < LAFRn → m is a suspect according to local average n exchanges counters information with neighboring nodes m n y

  47. Enter Detection Mode: Listening State m is a suspect. Enter Detection mode – Listening State x Radio range of m n enters Detecting state by invoking Misbehavior Detection procedure. m is a suspect. Enter Detection mode – Listening State m n m is a suspect. Enter Detection model – Listening State y

  48. Detection Mode: Detecting State (1) x resets the delay timer and stays in Listening State x n generates and broadcasts a Detection packet n broadcasts a Detection packet two more times m n Detection packet is just a dummy data packet y resets the delay timer and stays in Listening State y

  49. Detection Mode: Detecting State (2) x exits Listening State x If m forwards the Detection packet n exits Listening State m n n forwards m’s Location Discovery packet y exits Listening State y

  50. Detection Mode: Detecting State (3) x marks m as misbehavior x drops m’s Location Discovery pakcet x If m drops all three Detection packets n drops m’s Location Discovery packet n marks m as misbehavior m n y drops m’s Location Discovery packet y marks m as misbehavior y

More Related