GTU-MCA-SEM IV - Fundamentals of Networking

1. THE NETWORK LAYER Chapter 5

10. COMPARISON OF VIRTUAL-CIRCUIT AND DATAGRAM Internet ATM

17. DIJKSTRA ALGORITHM (3) 1 Initialization: 2 N = {A} 3 For all nodes v 4 If v adjacent to A then 5 D(v) = c(A,v) 6 Else D(v) = infinity 8 Loop 9 Find w not in N such that D(w) is a minimum 10 Add w to N 11 Update D(v) for all v adjacent to w and not in N: 12 D(v) = min( D(v), D(w) + c(w,v) ) /* new cost to v is either old cost to v or known shortest path cost to w plus cost from w to v */ 13 until all nodes in N C version of this algorithm is available in book v w D(v) c(w,v) D(w) A

20. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 24 18 2 9 14 15 5 30 20 44 16 11 6 19 6        0 distance label S = { } PQ = { s, 2, 3, 4, 5, 6, 7, t }

21. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 24 18 2 9 14 15 5 30 20 44 16 11 6 19 6        0 distance label S = { } PQ = { s, 2, 3, 4, 5, 6, 7, t } delmin

22. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 24 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9    14  0 distance label S = { s } PQ = { 2, 3, 4, 5, 6, 7, t } decrease key  X   X X

23. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 24 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9    14  0 distance label S = { s } PQ = { 2, 3, 4, 5, 6, 7, t }  X   X X delmin

24. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 24 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9    14  0 S = { s, 2 } PQ = { 3, 4, 5, 6, 7, t }  X   X X

25. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 24 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9    14  0 S = { s, 2 } PQ = { 3, 4, 5, 6, 7, t }  X   X X decrease key X 33

26. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 24 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9    14  0 S = { s, 2 } PQ = { 3, 4, 5, 6, 7, t }  X   X X X 33 delmin

27. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 24 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9    14  0 S = { s, 2, 6 } PQ = { 3, 4, 5, 7, t }  X   X X X 33 44 X X 32

28. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 24 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9   14  0 S = { s, 2, 6 } PQ = { 3, 4, 5, 7, t }  X   X X 44 X delmin  X 33 X 32

29. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9   14  0 S = { s, 2, 6, 7 } PQ = { 3, 4, 5, t }  X   X X 44 X 35 X 59 X 24  X 33 X 32

30. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 24 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9   14  0 S = { s, 2, 6, 7 } PQ = { 3, 4, 5, t }  X   X X 44 X 35 X 59 X delmin  X 33 X 32

31. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 24 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9   14  0 S = { s, 2, 3, 6, 7 } PQ = { 4, 5, t }  X   X X 44 X 35 X 59 X X 51 X 34  X 33 X 32

32. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9   14  0 S = { s, 2, 3, 6, 7 } PQ = { 4, 5, t }  X   X X 44 X 35 X 59 X X 51 X 34 delmin  X 33 X 32 24

33. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9   14  0 S = { s, 2, 3, 5, 6, 7 } PQ = { 4, t }  X   X X 44 X 35 X 59 X X 51 X 34 24 X 50 X 45  X 33 X 32

34. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9   14  0 S = { s, 2, 3, 5, 6, 7 } PQ = { 4, t }  X   X X 44 X 35 X 59 X X 51 X 34 24 X 50 X 45 delmin  X 33 X 32

35. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9   14  0 S = { s, 2, 3, 4, 5, 6, 7 } PQ = { t }  X   X X 44 X 35 X 59 X X 51 X 34 24 X 50 X 45  X 33 X 32

36. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9   14  0 S = { s, 2, 3, 4, 5, 6, 7 } PQ = { t }  X   X X 44 X 35 X 59 X X 51 X 34 X 50 X 45 delmin  X 33 X 32 24

37. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 24 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9   14  0 S = { s, 2, 3, 4, 5, 6, 7, t } PQ = { }  X   X X 44 X 35 X 59 X X 51 X 34 X 50 X 45  X 33 X 32

38. DIJKSTRA'S SHORTEST PATH ALGORITHM s 3 t 2 6 7 4 5 24 18 2 9 14 15 5 30 20 44 16 11 6 19 6 15 9   14  0 S = { s, 2, 3, 4, 5, 6, 7, t } PQ = { }  X   X X 44 X 35 X 59 X X 51 X 34 X 50 X 45  X 33 X 32

39. DIJKSTRA'S ALGORITHM - PSEUDOCODE dist[s] ←0 (distance to source vertex is zero) for all v ∈ V–{s} do dist[v] ←∞ (set all other distances to infinity) S←∅ (S, the set of visited vertices is initially empty) Q←V (Q, the queue initially contains all vertices) while Q ≠∅ (while the queue is not empty) do u ← mindistance (Q,dist) (select the element of Q with the min. distance) S←S∪{u} (add u to list of visited vertices) for all v ∈ neighbors[u] do if dist[v] > dist[u] + w(u, v) (if new shortest path found) then d[v] ←d[u] + w(u, v) (set new value of shortest path) (if desired, add traceback code) return dist

40. DIJKSTRA ANIMATED EXAMPLE

41. DIJKSTRA ANIMATED EXAMPLE

42. DIJKSTRA ANIMATED EXAMPLE

43. DIJKSTRA ANIMATED EXAMPLE

44. DIJKSTRA ANIMATED EXAMPLE

45. DIJKSTRA ANIMATED EXAMPLE

46. DIJKSTRA ANIMATED EXAMPLE

47. DIJKSTRA ANIMATED EXAMPLE

48. DIJKSTRA ANIMATED EXAMPLE

49. DIJKSTRA ANIMATED EXAMPLE

50. One more Ex:

62. LINK STATE ROUTING (3) The link state packets for this subnet. The packet buffer for router B, Used in step 

88. MOBILE IP

95. Remote host and mobile host communication

96. Mobile IP has two addresses for a mobile host: one home address and one care-of address. The home address is permanent; the care-of address changes as the mobile host moves from one network to another.

97. Registration request and reply

98. Data transfer

108. CONGESTION

124. Virtual-circuit routing Traditional Method MPLS it is not possible to group several distinct paths with different end points onto the same virtual-circuit identifier because there would be no way to distinguish them at the final destination. With MPLS, the packets still contain their final destination address + label , so that at the end of the labeled route the label header can be removed and forwarding can continue the usual way , using the network layer destination address. forwarding table construction in VC when a user wants to establish a connection, a setup packet is launched into the network to create the path and make the forwarding table entries forwarding table construction in MPLS there is no setup phase for each connection instead there are two ways for the forwarding table entries to be created. In the data-driven approach , Control-driven approach

135. IPV6

140. IPv4 Header IPv6 Header - field ’ s name kept from IPv4 to IPv6 - fields not kept in IPv6 - Name & position changed in IPv6 - New field in IPv6 Legend Version IHL Type of Service Total Length Identification Flags Fragment Offset Time to Live Protocol Header Checksum Source Address Destination Address Options Padding Version Traffic Class Flow Label Payload Length Next Header Hop Limit Source Address Destination Address

143. EXTENSION HEADERS next header = TCP TCP header + data IPv6 header next header = Routing TCP header + data Routing header next header = TCP IPv6 header next header = Routing fragment of TCP header + data Routing header next header = Fragment Fragment header next header = TCP IPv6 header

146. IPV6 TECHNOLOGY SCOPE IP Service IPv4 Solution IPv6 Solution Mobile IP with Direct Routing DHCP Mobile IP IGMP/ PIM/Multicast BGP IP Multicast MLD/ PIM/Multicast BGP, Scope Identifier Mobility Autoconfiguration Serverless , Reconfiguration , DHCP 32-bit, Network Address Translation 128-bit , Multiple Scopes Addressing Range Quality-of-Service Differentiated Service, Integrated Service Differentiated Service, Integrated Service Security IPSec Mandated, works End-to-End IPSec