Shortest Paths (Dijkstras Algorithm) 1. For each of the graphs below
In fact I will maintain two elements in the table
Review: Routing in Packet Networks Shortest Path Algorithms
How are routing tables determined? ? Who determines table entries? When do routing table entries change? ... Dijkstra's algorithm: example.
Programmatic implementation of the Dijkstra algorithm in the
finding paths in a graph using Dijkstra's algorithm set as a sequence of the example of the database tables
Weighted Sum-Dijkstras Algorithm in Best Path Identification based
Dijkstra's Algorithm is a shortest path algorithm that considers a single criterion only. Table 3. Weight allocation of Different Criteria for Example.
Dijsktras Algorithm
Dijkstra's algorithm: example (Step1) hop in shortest path used in forwarding table ... Example: setting forwarding table in router 1d.
Networking: Routing Algorithms
Dijkstra's algorithm: Example. • Source is node u. Resulting forwarding table in u: ... network in order to determine its forwarding table.
Dijkstras Algorithm
Example: For shortest path to C why do we choose edge (B
Priority Queues and Dijkstras Algorithm ? - Mo Chen † Rezaul
12 oct. 2007 Table 1: Amortized I/O bounds for heaps with Decrease-Keys (N = # items in queue B = block size
Dijkstras algorithm: another example
Node u's rouTng table: Shortest path from u to w according to above result. A. 5 through v. B. 4 through x. C. 3 through x. D. 3 through y.
EE 122: Shortest Path Routing
Individual router creating a forwarding table use Dijkstra to compute the shortest path to every other ... Example: Dijkstra's Algorithm.
Page 1
Review:
Routing in Packet Networks
Shortest Path Algorithms:
Dijkstra's & Bellman-Ford
2Routing:ȱIssues
Whoȱdeterminesȱtableȱentries?
Howȱtoȱcontrolȱtableȱsize?
Page 2
3Scalability
4Techniqueȱ1:ȱFlooding
Advantages:
Disadvantages:
ȬWasteȱcapacityȱofȱlinks
Router
Page 3
5HopȬbyȬHop/SourceȱRouting
HopȬbyȬhopȱrouting
ȬExample:ȱIP
Sourceȱrouting
6SourceȱRouting
01320 13 2 0 13 2 0 13 2 301
301
301
Switch 3
Host B
Switch 2
Host ASwitch 1
Page 4
7DistributedȱRoutingȱAlgorithms
ȬLinkȱstateȱrouting
ȬDistanceȱvectorȱrouting
8LinkȱStateȱvsDistanceȱVector
Bothȱassumeȱthat
Bothȱfindȱglobalinformation
Page 5
9LinkȱStateȱAlgorithm
ȬTopologyȱofȱtheȱnetwork
pathsLinkȬState
10TopologyȱDissemination
ȬLSPȱcontains
ȬUsingȱcontrolledȱflooding
LinkȬState
Page 6
11Dijkstra'sȱAlgorithm
Givenȱtheȱnetworkȱtopology
destination?Someȱnotation
ȬX:ȱsourceȱnode
far •Nȱisȱinitiallyȱempty 12Algorithmȱ(atȱNodeȱX)
Initialization
ȬNȱ=ȱ{X}
ȬForȱallȱnodesȱV
LoopȬAddȱUȱintoȱsetȱN
Page 7
13LinkȬState
14Dijkstra'sȱalgorithm:ȱexample
Step 0 1 2 3 45start N
A AD ADE ADEB ADEBCADEBCFD(B),p(B)
2,A 2,A2,AD(C),p(C)
5,A 4,D 3,E3,ED(D),p(D)
1,AD(E),p(E)
infinity2,DD(F),p(F)
infinity infinity 4,E 4,E 4,E A ED CB F 2 2 13 11 2535
LinkȬState
Page 8
15 A ED CB F 2 2 13 11 2535
RoutingȱTableȱComputation
dest next BB CD DD ED FDLinkȬState
16DistanceȱVectorȱRouting
ȬComputesȱ"shortestȱpaths"
•D XPage 9
17DistanceȱTable:ȱExample
A E D CB 7 8 1 212 D () A B C DA 1 7 6 4B 14 8 9 11D 5 5 4 2
Ecost to destination via
destinationDistanceȱVector
18 D () A B C DA 1 7 6 4B 14 8 9 11D 5 5 4 2Ecost to destination via
destination A B C DA,1 D,5 D,4 D,2Outgoing link
to use, cost destinationDistance tableRouting table
DistanceȱVector
Page 10
19Iterative:
continuesȱuntilȱnoȱnodesȱ exchangeȱinfo. selfȬterminating:ȱnoȱ"signal" toȱstopAsynchronous:
nodesȱneedȱnotexchangeȱ info/iterateȱinȱlockȱstep!Distributed:
eachȱnodeȱtalksȱonlywithȱ directlyȬattachedȱneighborsDistanceȱTableȱdataȱstructure
Eachȱnodeȱhasȱitsȱown
neighborȱtoȱnode neighborȱZ:D (Y,Z)
Xdistance fromX to
Y, viaZ as next hop
c(X,Z) + min {D (Y,w)} Z wDistanceȱVector
20Iterative,ȱasynchronous:ȱeachȱ
iterationȱcausedȱby:ȱLocalȱlinkȱcostȱchangeȱ
Distributed:
anyȱdestinationȱchanges neighborsȱifȱȱnecessary waitfor (change in local link cost or msg from neighbor) recomputedistance table if least cost path to any dest has changed, notify neighborsEach node:
DistanceȱVector
Page 11
21XZ 12 7 Y
D (Y,Z)
X c(X,Z) + min {D (Y,w)} w7+1 = 8
ZD (Z,Y)
X c(X,Y) + min {D (Z,w)} w2+1 = 3
YDistanceȱVector
22XZ 12 7 Y
DistanceȱVector
Page 12
23ConvergenceȱofȱDVȱRouting
Updatesȱdistanceȱtable
neighbors XZ 14 50Y 1 algorithm terminates "good news travels fast"
DistanceȱVector
24ProblemsȱwithȱDVȱRouting
Linkȱcostȱchanges:
Goodȱnewsȱtravelsȱfastȱ
Badȱnewsȱtravelsȱslow
Ȭ"CountȱtoȱInfinity"problem!
XZ 14 50Y 60
algorithm continues on!
DistanceȱVector
Page 13
25CountȬtoȬInfinityȱProblem
XYZ 11 2DistanceȱVector
26Splitȱhorizon
ȬAȱrouterȱnever advertisesȱtheȱcostȱofȱaȱdestinationȱtoȱaȱ neighborȬAcceleratesȱconvergence
DistanceȱVector
Page 14
27won'tȱrouteȱtoȱXȱviaȱZ) XZ 14 50
Y 60
algorithm terminates
DistanceȱVector
28LinkȱStateȱvsDistanceȱVector
Tellsȱeveryoneȱaboutȱ
neighborsControlledȱfloodingȱtoȱ
exchangeȱlinkȱstateDijkstra'sȱalgorithm
Eachȱrouterȱcomputesȱitsȱ
ownȱtableMayȱhaveȱoscillations
OpenȱShortestȱPathȱFirstȱ
(OSPF)Tellsȱneighborsȱaboutȱ
everyoneExchangesȱdistanceȱ
vectorsȱwithȱneighborsBellmanȬFordȱalgorithm
byȱothersMayȱhaveȱroutingȱloops
RoutingȱInformationȱ
Protocolȱ(RIP)
quotesdbs_dbs21.pdfusesText_27[PDF] dijkstra algorithm java explained
[PDF] dijkstra algorithm mit
[PDF] dijkstra algorithm pdf
[PDF] dijkstra algorithm ppt
[PDF] dijkstra algorithm pseudocode
[PDF] dijkstra algorithm python
[PDF] dijkstra algorithm runtime
[PDF] dijkstra algorithm space complexity
[PDF] dijkstra algorithm table
[PDF] dijkstra algorithm time and space complexity
[PDF] dijkstra algorithm time complexity
[PDF] dijkstra algorithm time complexity proof
[PDF] dijkstra algorithm visualization
[PDF] dijkstra pseudocode