1 / 35

A Routing Protocol for Space Communication

A Routing Protocol for Space Communication. By: Nouman Bantan Advisor: Dr. Javed I. Khan Friday, February 16, 2007. Current Mobility. Space Mobility. Future Network. Mars Colonies. Mars Satellite Constellation. Earth-Sun LaGrange Point Satellite. Mercury Satellite Constellation.

ayla
Download Presentation

A Routing Protocol for Space Communication

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. A Routing Protocol for Space Communication By: Nouman Bantan Advisor: Dr. Javed I. Khan Friday, February 16, 2007

  2. Current Mobility

  3. Space Mobility

  4. Future Network Mars Colonies Mars Satellite Constellation Earth-Sun LaGrange Point Satellite Mercury Satellite Constellation MoonColony Phobos Colony EarthSatellite Constellations Moon Satellite Constellation Venus Satellite Constellation AsteroidBelt Satellites Earth-Sun LaGrange Point Satellite Space Station Comet Temple1 Colony Space Shuttle

  5. Table of Contents • Space Challenges • Previous Work • Our Space Routing Protocol • The Routing Algorithm • SOSPF Analysis • Dissertation Contribution

  6. Space Communication Challenges • Use of network state information • Where is the routing table created • Router Mobility • Predictable • Unpredictable • Convergence Stability Period Vs Convergence Period Convergence Period Stability Period Time All routing tables have converged A link is down All routing tables have converged

  7. Intermittent Path Long Delay More Space Communication Challenges (k, l) Up Traditional Path between k, l, and m Down (k, l) Up (l, m) Down Up (l, m) Up Down Down (k, l) + (l, m) (k, l) + (l, m) Up Up Down Down Time Time

  8. Table of Contents • Space challenges • Previous Work • The SOSPF routing protocol • The Routing Algorithm • SOSPF Analysis • Dissertation Contribution

  9. Previous Works: ASCoT • The NASA Autonomous Space Communications Technology (ASCoT) [Gnawali 05] • depends on underlying systems which provides • Navigation information • Local status • Ability to send and receive messages • Link trajectories, together with link attributes are disseminated throughout the network. • Then, each router can independently compute paths using a modified Dijkstra’s algorithm • No intermittent links support • Single point of failure

  10. Previous Work: STRF • Space Time Routing Framework (STRF) construct space-time routing tables [Merugu 04] • The next hop is selected from the current as well as the possible future neighbors. • Same size messages require the same propagation delay. • STRF supports intermittent links

  11. Table of Contents • Space challenges • Previous Work • The SOSPF routing protocol • The Routing Algorithm • SOSPF Analysis • Dissertation Contribution

  12. SOSPF Routing Protocol • Area Structure • Hello Protocol • Neighbor Structure • Predictable Model • Advertisements • Database Exchange Protocol • Flooding • Calculating Routing Table

  13. MC2 MC1 MC3 MC4 SOSPF Areas Architecture M2 • Satellite constellation are • Space colony area • Celestial object area M1 M6 M3 M4 M5 Mars Celestial Object Area Mars’s Satellite Constellation Area Celestial Object Area* M1,M2, M3, M4,M5, and M6 MC1, MC2, MC3, and MC4 M1 MC3 Mars’s Space Colony Area

  14. Area Border Routers: Satellite Constellation Border Router (SCBR) Earth-Moon Satellite Constellation 1’s Orbit (Area 1:3:1:1) Earth-Moon Satellite Constellation 2’s Orbit (Area 1:3:1:2) EM5 EM3 Space Shuttle 1 (Area 1:3:1:3) SP1 EM1 EM2 SCBR Members of Area 1:3:1 EM4 1:3:1 1:3:1:1 1:3:1:2 1:3:1:3

  15. Area Border Routers: Celestial Object Border Router (COBR) Earth Satellite Constellation 2’s Orbit (Area 1:3:2) Space Shuttle 1(Area 1:3:1:3) EM5 EM2 E5 SP1 EM3 EM1 E3 EM4 E2 E6 Members of Area 1:3 Members of Area 1:3:1 E1 E4 Earth-Moon’s Orbit (Area 1:3:1) Earth Satellite Constellation 3’s Orbit (Area 1:3:3) SCBR COBR

  16. SOSPF Neighbor States Reached Maximum Down No Recurrence Hello Received Init Two-Way Received Awaken and Unsynchronized ExStart Negotiation Done Unsynchronized Exchange Exchange Done Sleep Loading Done Sleeping Loading Full Awaken and Ready

  17. SOSPF Advertisements: Space Router-LSA (SR-LSA)

  18. SOSPF Advertisements: When an SR-LSA is Generated • An SOSPF router becomes operational • An SOSPF router changes its Propagation Delay • An SOSPF router changes its six orbital space parameters • An SOSPF router changes its calculating method tag • A new SOSPF router is found • A Link Failed

  19. SOSPF Advertisements: Area Membership-LSA (AM-LSA) Members of (Area 1:4) Mars Satellite Constellation 2’s Orbit(Area 1:4:1) M12 M2 M1 M3 Mars Satellite Constellation 2’s Orbit (Area 1:4:2) M11 M6 M4 SCBR M10 M5 M1’s Neighboring Routers List for Area 1:4 M1’s Neighboring Routers List for Area 1:4:1 M1’s AM-LSA

  20. SOSPF Advertisements: When an AM-LSA is Generated • An SOSPF router becomes operational • Invitations to a new area • Joining an area • Failed neighboring router • Bad AM-LSA • …, and a few more

  21. SOSPF Advertisements: Area Border Router (ABR) List Mars Satellite Constellation 2’s Orbit(Area 1:4:1) M12 Members of (Area 1:4) M2 M1 M3 Mars Satellite Constellation 2’s Orbit (Area 1:4:2) M11 M6 M4 SCBR M10 M5 ABR List for M1-M6

  22. Example Setup E3 E5 Sun Area 1 E4 SP E2 E1 M2 Earth Area 1:3 Mars Area 1:4 M1 M3 Earth SC Area 1:3:1 Earth SC Area 1:3:2 Mars SC Area 1:4:1 Mars SC Area 1:4:2 M4 SCBR COBR

  23. Example: SP Joins Area 1:3 1 - SP Sends hello packet to E2 and E5 2 - SP Exchanges routing information with E2 and E5 3 - E2 forwards the new LSAs to the members of area 1:3:1. 4 - E2 forwards the new LSAs to the member of area 1 5 - Members of 1:3:1 flood the received LSAs to each other. 6 - We assume that M1 does not SP’s trajectory; thus, when M1 receive SP’s SR-LSA, M1 exchanges the required information with E2. 7 - M1 floods SP to 1:4 and 1:4:1 8 - Members of 1:4 flood the SP’s SR-LSA E4 5 E5 E1 5 2 1 3 E3 3 2 SP 1 E2 4 M2 M3 8 6 7 7 8 M4 M1 SCBR COBR Time: 1:00AM

  24. Table of Contents • Space challenges • Previous Work • The SOSPF routing protocol • The Routing Algorithm • SOSPF Analysis • Dissertation Contribution

  25. The Shortest Delay Intermittent Pathway (SDIP) Routing Algorithm • Input • Cost in seconds between x and y (cxy) • Beginning of active time between x and y (bxy) • Ending of active time between x and y (exy) • Delay measured as time between x and y (dxy) i.e., • dxy = bxy + cxy • Output • Path from x to y (pxy) • Delay measured as time between x and y (dxy) pxy Link Status cxy bxy dxy exy

  26. SDIP Routing Algorithm: Valid Combined Path (Case 1) • If dik < bkj and dkj < current dij Then pij = pik + pkj dik Paths bkj dkj cij bij dij eij

  27. SDIP Routing Algorithm: Valid Combined Path (Case 2) • If dik + ckj < ekj and dik + ckj < current dij Then pij = pik + pkj dik Paths pkj ckj bkj ekj cij eij dij bij

  28. SDIP Routing Algorithm: Invalid Combined Path • If dik + ckj ≥ ekj Then pik + pkj is invalid combined path dik Paths ckj ekj

  29. Table of Contents • Space challenges • Previous Work • The SOSPF routing protocol • The Routing Algorithm • SOSPF Analysis • Dissertation Contribution

  30. Transmit 1000 Packets from Earth to Mars Packet size = 112KB – 128 KB Bandwidth = 128Kbps At 0:0:0 On August 1, 2002, Simulation Duration = 1 hour End to End Delay Simulation

  31. 1 2 Number of Propagated Packets 3 4 SOSPF Scalability Sun Area Scalability Question: How much overhead when the number of SOSPF routers increases? Answer: The answer to this question is highly dependent on the topology of the network. Planet Area Moon Area Constellation Area

  32. SOSPF Stability t1 = Time of the interruption t2 = Time of when the interruption is detected t3 = Time of when all effected nodes converge to a solution t4 = Time of the next interruption Stability = F – (D + P) F D P t3 t2 F t4 t1 Time

  33. A satellite network with a diameter of 1013 km. 5000 SOSPF routers are scattered using a uniform random function The failure interval is 6666 seconds. CT = Current Technology CT Stability Simulation Four Levels Three Levels Two Levels

  34. Dissertation Contributions • SOSPF is the routing protocol for space • Define Logical Areas • Predicted Mobility • Detects Failed Links (first dynamic error detection mechanism in space) • Maintains Routing Accuracy • SDIP routing algorithm • Provides scheduling solutions for intermittent link • Improvement of current technology • Applicable for Earth-like environment such as: • Automobile Networks • Sensor Networks

  35. Publications • Bantan, N. 2006. Space OSPF. In the Fifth Space Internetworking Workshop – presentation paper (Baltimore, Maryland, United States). September 2006. http://www.hynet.umd.edu/Space_Internet_Workshop/pres/A004.pdf • Bantan, N. and Khan, J. 2007. SOSPF- a new routing protocol for space. In Proceedings of The 25th AIAA International Communications Satellite Systems Conference (Seoul, South Korea). April 2007. • Bantan, N. and Khan, J. 2006. Space OSPF - shortest delay intermittent pathway routing with mobile routers. In the Fifth Space Internetworking Workshop – presentation paper (Baltimore, Maryland, United States). September 2006. http://www.hynet.umd.edu/Space_Internet_Workshop/pres/A008.pdf

More Related