1. Computer network technology
Prerequisites
Computer network technology
Data communication
Basics of networking
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Unit-1 Network Layer

2. Networking Components
Prerequisites
Networks
Topologies
Networking Components
Cables
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3. Seven layers of the OSI model
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4. The interaction between layers in the OSI model
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5. An exchange using the OSI model
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6. Summary of layers
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7. TCP/IP and OSI model
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8. Addressing
Four levels of addresses are used in an internet employing the TCP/IP protocols:
Physical Adresses
Logical Adresses
Port Addresses
Specific Addresses
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Unit-1 Network Layer

9. Addresses in TCP/IP
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10. Relationship of layers and addresses in TCP/IP
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11. Physical addresses
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12. 07:01:02:01:2C:4B A 6-byte (12 hexadecimal digits) physical address.
most local-area networks use a 48-bit (6-byte) physical address written as 12 hexadecimal digits; every byte (2 hexadecimal digits) is separated by a colon, as shown below:
07:01:02:01:2C:4B A 6-byte (12 hexadecimal digits) physical address.
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Unit-1 Network Layer

13. Port addresses
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14. A 16-bit port address represented as one single number.
port address is a 16-bit address represented by one decimal number as shown.
753
A 16-bit port address represented as one single number.
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Unit-1 Network Layer

15. Let’s take a tour of Network layer now………
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Unit-1 Network Layer

16. Network Layer Design Issues
Store-and-Forward Packet Switching
Services Provided to the Transport Layer
Implementation of Connectionless Service
Implementation of Connection-Oriented Service
Comparison of Virtual-Circuit and Datagram Subnets
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Unit-1 Network Layer

17. Store-and-Forward Packet Switching
fig 5-1
The environment of the network layer protocols.
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Unit-1 Network Layer

18. Implementation of Connectionless Service
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19. Implementation of Connection-Oriented Service
Routing within a datagram subnet
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20. Comparison of Virtual-Circuit and Datagram Subnets
5-4
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21. Routing Algorithms Overview
Non adaptive/Static Algorithms
do not base their routing decisions on measurements or estimates of the current traffic and topology.
Adaptive /Dynamic Algorithms
attempt to change their routing decisions to reflect changes in topology and the current traffic.
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Unit-1 Network Layer

22. Routing Algorithms Routing algorithms Static routing algorithms
Shortest Path Routing
Broadcast Routing
Multicast Routing
Flooding
Dynamic routing algorithms
Distance Vector Routing
Link State Routing
The Optimality Principle
Hierarchical Routing
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Unit-1 Network Layer

23. The Optimality Principle
(a) A subnet. (b) A sink tree for router B.
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24. Shortest Path Routing
The first 5 steps used in computing the shortest path from A to D. The arrows indicate the working node.
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25. A Graph of the Subnet Undirected Weighted B C 7 2 3 2 3 E F 2 A D 2 1
Geographic Distance B C 7 2 3 2 3 E F 2 A D 2 1 2 6 4 G H
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26. Dijkstra’s Algorithm B C 7 2 3 2 3 E F 2 A D 2 1 2 6 4 G H 5/25/2019
Each node is labeled (in parentheses) with its distance from the source node along the best known path. B C 7 2 3 2 3 E F 2 A D 2 1 2 6 4 G H
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27. Dijkstra’s Algorithm (cont’d)
We want to find the shortest path from A to D.
Initially, no paths are known, so all nodes are labeled with infinity.
B(¥,-)
C(¥,-)
E(¥,-)
F(¥,-) A
D(¥,-)
G(¥,-)
H(¥,-)
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28. Dijkstra’s Algorithm (cont’d)
We start out by marking node A (the working node) as permanent.
We examine each of the nodes adjacent A, relabeling each one with the distance to A.
B(2, A)
C(¥,-) 2
E(¥,-)
F(¥,-) A
D(¥,-) 6
G(6, A)
H(¥,-)
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Unit-1 Network Layer

29. Dijkstra’s Algorithm (cont’d)
We make B with the smallest label permanent.
B becomes the new working node.
B(2, A)
C(¥,-)
E(¥,-)
F(¥,-) A
D(¥,-)
G(6, A)
H(¥,-)
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Unit-1 Network Layer

30. Dijkstra’s Algorithm (cont’d)
We examine each of the nodes adjacent B, relabeling each one with the distance to B.
B(2, A)
C(9, B) 7 2
E(4, B)
F(¥,-) A
D(¥,-)
G(6, A)
H(¥,-)
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31. Dijkstra’s Algorithm (cont’d)
We make E with the smallest label permanent.
E becomes the new working node.
B(2, A)
C(9, B)
E(4, B)
F(¥,-) A
D(¥,-)
G(6, A)
H(¥,-)
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Unit-1 Network Layer

32. Dijkstra’s Algorithm (cont’d)
We examine each of the nodes adjacent E, relabeling each one with the distance to E.
B(2, A)
C(9, B)
E(4, B)
F(6, E) A
D(¥,-) 2 1
G(5, E)
H(¥,-)
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Unit-1 Network Layer

33. Dijkstra’s Algorithm (cont’d)
We make G with the smallest label permanent.
G becomes the new working node.
B(2, A)
C(9, B)
E(4, B)
F(6, E) A
D(¥,-)
G(5, E)
H(¥,-)
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Unit-1 Network Layer

34. Dijkstra’s Algorithm (cont’d)
We examine each of the nodes adjacent G, relabeling each one with the distance to G.
B(2, A)
C(9, B)
E(4, B)
F(6, E) A
D(¥,-) 4
G(5, E)
H(9, G)
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Unit-1 Network Layer

35. Dijkstra’s Algorithm (cont’d)
We make F with the smallest label permanent.
F becomes the new working node.
B(2, A)
C(9, B)
E(4, B)
F(6, E) A
D(¥,-)
G(5, E)
H(9, G)
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Unit-1 Network Layer

36. Dijkstra’s Algorithm (cont’d)
We examine each of the nodes adjacent F, relabeling each one with the distance to F.
B(2, A)
C(9, B) 3
E(4, B)
F(6, E) A
D(¥,-) 2
G(5, E)
H(8, F)
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Unit-1 Network Layer

37. Dijkstra’s Algorithm (cont’d)
We make H with the smallest label permanent.
H becomes the new working node.
B(2, A)
C(9, B)
E(4, B)
F(6, E) A
D(¥,-)
G(5, E)
H(8, F)
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Unit-1 Network Layer

38. Dijkstra’s Algorithm (cont’d)
We examine each of the nodes adjacent H, relabeling each one with the distance to H.
B(2, A)
C(9, B)
E(4, B)
F(6, E) A
D(10, F) 2
G(5, E)
H(8, F)
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Unit-1 Network Layer

39. Dijkstra’s Algorithm (cont’d)
We make C with the smallest label permanent.
C becomes the new working node.
B(2, A)
C(9, B)
E(4, B)
F(6, E) A
D(10, F)
G(5, E)
H(8, F)
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Unit-1 Network Layer

40. Dijkstra’s Algorithm (cont’d)
We examine each of the nodes adjacent C, relabeling each one with the distance to C.
B(2, A)
C(9, B) 3
E(4, B)
F(6, E) A
D(10, F)
G(5, E)
H(8, F)
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Unit-1 Network Layer

41. Dijkstra’s Algorithm (cont’d)
We make D with the smallest label permanent.
D becomes the new working node.
B(2, A)
C(9, B)
E(4, B)
F(6, E) A
D(10, F)
G(5, E)
H(8, F)
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Unit-1 Network Layer

42. Dijkstra’s Algorithm (cont’d)
The shortest path from A to D follows.
B(2, A)
C(9, B)
E(4, B)
F(6, E) A
D(10, H)
G(5, E)
H(8, F)
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Unit-1 Network Layer