a routing protocol for space communication
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
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A Routing Protocol for Space A Routing Protocol for Space CommunicationCommunication
By: Nouman Bantan By: Nouman Bantan
Advisor: Dr. Javed I. KhanAdvisor: Dr. Javed I. Khan
Friday, February 16, 2007Friday, February 16, 2007
22
Current MobilityCurrent Mobility
33
Space MobilitySpace Mobility
44
Future NetworkFuture Network
Mars Colonies
Mars Satellite Constellation
Phobos Colony
Comet Temple1 Colony
Space Station
AsteroidBelt Satellites
Venus Satellite Constellation
MoonColony
Moon Satellite Constellation
Earth-Sun LaGrange Point Satellite
Earth-Sun LaGrange Point Satellite
Mercury Satellite Constellation
Space Shuttle
EarthSatellite Constellations
55
Table of ContentsTable of Contents
Space ChallengesSpace Challenges
Previous WorkPrevious Work
Our Space Routing ProtocolOur Space Routing Protocol
The Routing AlgorithmThe Routing Algorithm
SOSPF AnalysisSOSPF Analysis
Dissertation ContributionDissertation Contribution
66
Space Communication ChallengesSpace Communication Challenges
1.1. Use of network state informationUse of network state information2.2. Where is the routing table createdWhere is the routing table created3.3. Router MobilityRouter Mobility
PredictablePredictable UnpredictableUnpredictable
4.4. ConvergenceConvergence
All routing tables have converged
A link is down
Convergence Period
Stability Period
Time
Stability Period Vs Convergence Period
All routing tables have converged
77
More Space Communication More Space Communication ChallengesChallenges
5.5. Intermittent PathIntermittent Path
6.6. Long DelayLong Delay Intermittent Path between k, l, and m
(l, m)
(k, l) + (l, m)
(k, l)
Time
Down
Up
Down
Up
Down
Up
Traditional Path between k, l, and m
(l, m)
(k, l) + (l, m)
(k, l)
Down
Up
Down
Up
Down
Up
Time
88
Table of ContentsTable of Contents
Space challengesSpace challenges
Previous WorkPrevious Work
The SOSPF routing protocolThe SOSPF routing protocol
The Routing AlgorithmThe Routing Algorithm
SOSPF AnalysisSOSPF Analysis
Dissertation ContributionDissertation Contribution
99
Previous Works: ASCoTPrevious Works: ASCoT
The NASA Autonomous Space Communications The NASA Autonomous Space Communications Technology (ASCoT) [Gnawali 05Technology (ASCoT) [Gnawali 05]]– depends on underlying systems which providesdepends on underlying systems which provides
Navigation information Navigation information Local status Local status Ability to send and receive messagesAbility to send and receive messages
Link trajectories, together with link attributes are Link trajectories, together with link attributes are disseminated throughout the network. disseminated throughout the network. Then, each router can independently compute Then, each router can independently compute paths using a modified Dijkstra’s algorithmpaths using a modified Dijkstra’s algorithmNo intermittent links supportNo intermittent links supportSingle point of failureSingle point of failure
1010
Previous Work: STRFPrevious Work: STRF
Space Time Routing Framework (STRF) construct Space Time Routing Framework (STRF) construct space-time routing tables [Merugu 04]space-time routing tables [Merugu 04]The next hop is selected from the current as well as the The next hop is selected from the current as well as the possible future neighbors. possible future neighbors. Same size messages require the same propagation Same size messages require the same propagation delay.delay.STRF supports intermittent linksSTRF supports intermittent links
1111
Table of ContentsTable of Contents
Space challengesSpace challenges
Previous WorkPrevious Work
The SOSPF routing protocolThe SOSPF routing protocol
The Routing AlgorithmThe Routing Algorithm
SOSPF AnalysisSOSPF Analysis
Dissertation ContributionDissertation Contribution
1212
SOSPF Routing ProtocolSOSPF Routing Protocol
Area StructureArea StructureHello ProtocolHello ProtocolNeighbor StructureNeighbor StructurePredictable ModelPredictable ModelAdvertisementsAdvertisementsDatabase Exchange ProtocolDatabase Exchange ProtocolFloodingFloodingCalculating Routing TableCalculating Routing Table
1313
SOSPF Areas ArchitectureSOSPF Areas Architecture
Satellite constellation areSatellite constellation are
Space colony areaSpace colony area
Celestial object areaCelestial object area
Celestial Object Area*
MC1, MC2, MC3,
and MC4
M1,M2,M3, M4,M5,
and M6
M3
M5
M1
M6
M2
M4
Mars Celestial Object Area
M1MC3
Mars’s Satellite Constellation Area
MC1 MC2
MC4MC3
Mars’s Space Colony Area
1414
Area Border Routers: Area Border Routers: Satellite Constellation Border Router (SCBR)Satellite Constellation Border Router (SCBR)
EM1
EM2
EM3EM5
EM4
Earth-Moon Satellite Constellation 1’s Orbit (Area 1:3:1:1)
Area Members
1:3:1 EM1, EM4, and SP1
1:3:1:1 EM1, EM2, and EM3
1:3:1:2 EM4 and EM5
1:3:1:3 SP1
SCBR
1:3:1
1:3:1:21:3:1:1
Earth-Moon Satellite Constellation 2’s Orbit (Area 1:3:1:2)
SP1 Space Shuttle 1 (Area 1:3:1:3)
1:3:1:3
Members of Area 1:3:1
1515
Area Border Routers: Area Border Routers: Celestial Object Border Router (COBR)Celestial Object Border Router (COBR)
E3
EM1
EM2
EM3
E1
E2
EM5
EM4
E5
E6
E4
SCBRCOBR
Earth-Moon’s Orbit (Area 1:3:1)
Earth Satellite Constellation 3’s Orbit (Area 1:3:3)
Earth Satellite Constellation 2’s Orbit (Area 1:3:2)
SP1
Space Shuttle 1(Area 1:3:1:3)
Members of Area 1:3:1
Members of Area 1:3
1616
SOSPF Neighbor StatesSOSPF Neighbor States
ExStart
Down
Init
Exchange
LoadingFullSleepingAwaken and Ready
Awaken and Unsynchronized
Reached Maximum
Sleep
Unsynchronized
No Recurrence Hello Received
Two-Way Received
Exchange Done
Negotiation Done
Loading Done
1717
SOSPF Advertisements: SOSPF Advertisements: Space Router-LSA (SR-LSA)Space Router-LSA (SR-LSA)
Source Satellite Address 5F00:0000:C001:0400::/56
Destination Satellite Address 5F00:0000:c001:2C00::/56
Number of tuples 3
Tuple # 1
Begin time 2006:08:28:20:14:50
Connection Period 14400
Propagation Delay 15
Tuple # 2
Begin time 2006:08:29:40:30:05
Connection Period 2000
Propagation Delay 20
Tuple # 3
Begin time 2006:08:30:23:14:50
Connection Period 3000
Propagation Delay 20
1818
SOSPF Advertisements: SOSPF Advertisements: When an SR-LSA is GeneratedWhen an SR-LSA is Generated
1.1. An SOSPF router becomes operationalAn SOSPF router becomes operational2.2. An SOSPF router changes its An SOSPF router changes its
Propagation DelayPropagation Delay3.3. An SOSPF router changes its six orbital An SOSPF router changes its six orbital
space parametersspace parameters4.4. An SOSPF router changes its calculating An SOSPF router changes its calculating
method tagmethod tag5.5. A new SOSPF router is foundA new SOSPF router is found6.6. A Link FailedA Link Failed
1919
SOSPF Advertisements: SOSPF Advertisements: Area Membership-LSA (AM-LSA) Area Membership-LSA (AM-LSA)
M3
M5
M1
M12
M11
M10
Mars Satellite Constellation 2’s Orbit (Area 1:4:2)
Mars Satellite Constellation 2’s Orbit(Area 1:4:1)
SCBR
M6
M2
M4
Members of (Area 1:4)
Source Satellite Address
5F00:0000:B020::/48
# of tuples 1
# 1
Area ID 1:4
Area Members
M1, M12
Area Start Time
2007:01:11:20:14:50
Area Period
1400
# 2
Area ID 1:4:1
Area Members
M1,M2,M3, M4,M5,M6
Area Start Time
2007:28:28:20:14:50
Area Period
50400
M1’s AM-LSA
Number of entries 1
#1
Neighboring Routers M1,M12
Neighboring Start Time 2007:01:11:20:14:50
Neighboring Period 1400
M1’s Neighboring Routers List for Area 1:4
Number of entries 1
#1
Neighboring RoutersM1,M2,M3,M4,M5,M6
Neighboring Start Time 2007:08:28:20:14:50
Neighboring Period 50400
M1’s Neighboring Routers List
for Area 1:4:1
2020
1.1. An SOSPF router becomes An SOSPF router becomes operationaloperational
2.2. Invitations to a new areaInvitations to a new area
3.3. Joining an areaJoining an area
4.4. Failed neighboring routerFailed neighboring router
5.5. Bad AM-LSA Bad AM-LSA
6.6. ……, and a few more, and a few more
SOSPF Advertisements: SOSPF Advertisements: When an AM-LSA is GeneratedWhen an AM-LSA is Generated
2121
SOSPF Advertisements: SOSPF Advertisements: Area Border Router (ABR) ListArea Border Router (ABR) List
Area Border Router's ID
Area ID Membership Start Time Expiration Time
M11:4 2007:01:11:20:14:50 2007:01:11:20:35:13
1:4:1 2007:08:28:20:14:50 2007:08:29:10:14:50
M3
M5
M1
M12
M11
M10
Mars Satellite Constellation 2’s Orbit (Area 1:4:2)
Mars Satellite Constellation 2’s Orbit(Area 1:4:1)
SCBR
M6
M2
M4
Members of (Area 1:4)
ABR List for M1-M6
2222
Example SetupExample Setup
M3
M2E1
E5E3
M1
M4
E2SPE4
SCBRCOBR
EarthArea 1:3
EarthSC Area
1:3:2
Earth SC Area
1:3:1
SunArea
1
MarsArea 1:4
MarsSC Area
1:4:2
MarsSC Area
1:4:1
2323
Example: SP Joins Area 1:3Example: SP Joins Area 1:31 - SP Sends hello packet to E21 - SP Sends hello packet to E2 and E5 and E5 2 - SP Exchanges routing2 - SP Exchanges routing information with E2 and E5 information with E2 and E5 3 - E2 forwards the new LSAs to3 - E2 forwards the new LSAs to the members of area 1:3:1.the members of area 1:3:1.4 - E2 forwards the new LSAs to4 - E2 forwards the new LSAs to the member of area 1 the member of area 1 5 - Members of 1:3:1 flood the5 - Members of 1:3:1 flood the received LSAs to each other.received LSAs to each other.6 - We assume that M1 does not6 - We assume that M1 does not SP’s trajectory; thus, when M1SP’s trajectory; thus, when M1 receive SP’s SR-LSA, M1receive SP’s SR-LSA, M1 exchanges the requiredexchanges the required information with E2. information with E2. 7 - M1 floods SP to 1:4 and 1:4:1 7 - M1 floods SP to 1:4 and 1:4:1 8 - Members of 1:4 flood the SP’s 8 - Members of 1:4 flood the SP’s
SR-LSA SR-LSA
M3M2
E3
E5
M1
M4
E1
SPE2
5
123
1
Time: 1:00AM
E4
3
5
8
7 7
8
4
6
SCBRCOBR
2
2424
Table of ContentsTable of Contents
Space challengesSpace challenges
Previous WorkPrevious Work
The SOSPF routing protocolThe SOSPF routing protocol
The Routing AlgorithmThe Routing Algorithm
SOSPF AnalysisSOSPF Analysis
Dissertation ContributionDissertation Contribution
2525
The Shortest Delay Intermittent The Shortest Delay Intermittent Pathway (SDIP) Routing AlgorithmPathway (SDIP) Routing Algorithm
InputInput– Cost in seconds between Cost in seconds between xx and and yy ( (ccxyxy))– Beginning of active time between x and y (Beginning of active time between x and y (bbxyxy))– Ending of active time between x and y (Ending of active time between x and y (eexyxy))– Delay measured as time between Delay measured as time between xx and and yy ( (ddxyxy) i.e.,) i.e.,
ddxyxy = = bbxyxy + + ccxyxy
OutputOutput– Path from Path from xx to to yy ( (ppxyxy))– Delay measured as time between Delay measured as time between xx and and yy ( (ddxyxy))
Up
Down
Time exybxy dxy
Link
Sta
tus
cxypxy
2626
SDIP Routing Algorithm: SDIP Routing Algorithm: Valid Combined Path (Case 1)Valid Combined Path (Case 1)
If If ddikik < < bbkj kj and dand dkjkj < current < current ddijij
Then Then ppijij = p = pikik + + ppkjkj
pik
pkj
pik+pkj
Time
dik
bkjPat
hs
dkj
dijbij eij
cij
2727
SDIP Routing Algorithm: SDIP Routing Algorithm: Valid Combined Path (Case 2)Valid Combined Path (Case 2)
pik
pik+pkj
Time
ckj
bkj ekj
dik
Pat
hs
If If ddikik + + cckjkj < < eekj kj and dand dikik + + cckjkj < current < current ddijij
Then Then ppijij = p = pikik + + ppkjkj
dijbijeij
cij
pkj
2828
SDIP Routing Algorithm: SDIP Routing Algorithm: Invalid Combined PathInvalid Combined Path
If If ddikik + + cckjkj ≥ ≥ eekjkj
ThenThen p pikik + + ppkj kj is invalid combined pathis invalid combined path
pik
pkj
pik+pkj
Time
ckjPat
hs
ekj
dik
2929
Table of ContentsTable of Contents
Space challengesSpace challenges
Previous WorkPrevious Work
The SOSPF routing protocolThe SOSPF routing protocol
The Routing AlgorithmThe Routing Algorithm
SOSPF AnalysisSOSPF Analysis
Dissertation ContributionDissertation Contribution
3030
End to End Delay SimulationEnd to End Delay Simulation
Transmit 1000 Packets from Earth to MarsTransmit 1000 Packets from Earth to MarsPacket size = 112KB – 128 KBPacket size = 112KB – 128 KBBandwidth = 128Kbps Bandwidth = 128Kbps At 0:0:0 On August 1, 2002,At 0:0:0 On August 1, 2002,Simulation Duration = 1 hourSimulation Duration = 1 hour
Average Delay for Transmissions Between an Earth Satellite and a Mars Satellite
0
500
1000
1500
1 2 3 4 5 6 7Scnario Number
Sec
onds SOSPF
ASCoT
STRF
1)
2)
3)
4)
5)
6)
7)
3131
SOSPF ScalabilitySOSPF Scalability
Scenario
Levels
1 2 3 4
1 n n n n
2 n n/2 n/2 n/2
3 n n/4 n/8 n/16
4 n n/24 n/36 n/48
Propagated Packets Per Satellite Router
1
10
100
1000
10000
0 30
0
60
0
90
0
12
00
15
00
18
00
21
00
24
00
27
00
30
00
Number of Satellite Routers
2
1
3
4
Num
ber
of
Pro
paga
ted
Pac
kets
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.
Sun Area
Planet Area
Moon Area
Constellation Area
3232
SOSPF StabilitySOSPF Stability
tt11 = = Time of the interruptionTime of the interruption
tt22 = = Time of when the interruption is detectedTime of when the interruption is detected
tt33 = = Time of when all effected nodes converge to a solutionTime of when all effected nodes converge to a solution
tt44 = = Time of the next interruptionTime of the next interruption
Stability =Stability =
D P
Ft4
t2
t1
t3
Time
F – (D + P)F – (D + P)
F F
3333
Stability SimulationStability Simulation
Two LevelsThree Levels
Four Levels
A satellite network with a diameter of 1013 A satellite network with a diameter of 1013 km.km.5000 SOSPF routers are scattered using a 5000 SOSPF routers are scattered using a uniform random functionuniform random functionThe failure interval is 6666 seconds. The failure interval is 6666 seconds. CT = Current TechnologyCT = Current Technology
0
0.2
0.4
0.6
0.8
1
0.1
1 10 100
1000
10000Network Diameter (109 km)
(F -
(D
+ P
))/F RT
Two LevelsThree LevelsFour Levels
Moon
MarsJupiter
Neptune
0
0.2
0.4
0.6
0.8
1
0.1
1 10 100
1000
10000Network Diameter (109 km)
(F -
(D
+ P
))/F RT
Two LevelsThree LevelsFour Levels
Moon
MarsJupiter
Neptune
CT
3434
Dissertation ContributionsDissertation Contributions
1.1. SOSPF is the routing protocol for spaceSOSPF is the routing protocol for space– Define Logical AreasDefine Logical Areas– Predicted MobilityPredicted Mobility– Detects Failed Links (first dynamic error detection Detects Failed Links (first dynamic error detection
mechanism in space)mechanism in space)– Maintains Routing AccuracyMaintains Routing Accuracy
2.2. SDIP routing algorithm SDIP routing algorithm – Provides scheduling solutions for intermittent link– Improvement of current technology– Applicable for Earth-like environment such as:
Automobile NetworksSensor Networks
3535
PublicationsPublications
Bantan, N. 2006. Space OSPF. In Bantan, N. 2006. Space OSPF. In the Fifth Space Internetworking the Fifth Space Internetworking Workshop – presentation paperWorkshop – presentation paper (Baltimore, Maryland, United (Baltimore, Maryland, United States). September 2006. States). September 2006. http://www.hynet.umd.edu/Space_Internet_Workshop/pres/A004.pdfhttp://www.hynet.umd.edu/Space_Internet_Workshop/pres/A004.pdfBantan, N. and Khan, J. 2007. SOSPF- a new routing protocol for Bantan, N. and Khan, J. 2007. SOSPF- a new routing protocol for space. In space. In Proceedings of The 25th AIAA International Proceedings of The 25th AIAA International Communications Satellite Systems ConferenceCommunications Satellite Systems Conference (Seoul, South (Seoul, South Korea). April 2007.Korea). April 2007.Bantan, N. and Khan, J. 2006. Space OSPF - shortest delay Bantan, N. and Khan, J. 2006. Space OSPF - shortest delay intermittent pathway routing with mobile routers. In intermittent pathway routing with mobile routers. In the Fifth Space the Fifth Space Internetworking Workshop – presentation paperInternetworking Workshop – presentation paper (Baltimore, (Baltimore, Maryland, United States). September 2006. Maryland, United States). September 2006. http://www.hynet.umd.edu/Space_Internet_Workshop/pres/A008.pdfhttp://www.hynet.umd.edu/Space_Internet_Workshop/pres/A008.pdf