Computer network technology Prerequisites Computer network technology Data communication Basics of networking 5/25/2019 Unit-1 Network Layer

Networking Components Prerequisites Networks Topologies Networking Components Cables 5/25/2019 Unit-1 Network Layer

Seven layers of the OSI model 5/25/2019 Unit-1 Network Layer

The interaction between layers in the OSI model 5/25/2019 Unit-1 Network Layer

An exchange using the OSI model 5/25/2019 Unit-1 Network Layer

Summary of layers 5/25/2019 Unit-1 Network Layer

TCP/IP and OSI model 5/25/2019 Unit-1 Network Layer

Addressing Four levels of addresses are used in an internet employing the TCP/IP protocols: Physical Adresses Logical Adresses Port Addresses Specific Addresses 5/25/2019 Unit-1 Network Layer

Addresses in TCP/IP 5/25/2019 Unit-1 Network Layer

Relationship of layers and addresses in TCP/IP 5/25/2019 Unit-1 Network Layer

Physical addresses 5/25/2019 Unit-1 Network Layer

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. 5/25/2019 Unit-1 Network Layer

Port addresses 5/25/2019 Unit-1 Network Layer

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. 5/25/2019 Unit-1 Network Layer

Let’s take a tour of Network layer now……… 5/25/2019 Unit-1 Network Layer

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 5/25/2019 Unit-1 Network Layer

Store-and-Forward Packet Switching fig 5-1 The environment of the network layer protocols. 5/25/2019 Unit-1 Network Layer

Implementation of Connectionless Service 5/25/2019 Unit-1 Network Layer

Implementation of Connection-Oriented Service Routing within a datagram subnet 5/25/2019 Unit-1 Network Layer

Comparison of Virtual-Circuit and Datagram Subnets 5-4 5/25/2019 Unit-1 Network Layer

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. 5/25/2019 Unit-1 Network Layer

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 5/25/2019 Unit-1 Network Layer

The Optimality Principle (a) A subnet. (b) A sink tree for router B. 5/25/2019 Unit-1 Network Layer

Shortest Path Routing The first 5 steps used in computing the shortest path from A to D. The arrows indicate the working node. 5/25/2019 Unit-1 Network Layer

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 5/25/2019 Unit-1 Network Layer

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 5/25/2019 Unit-1 Network Layer

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(¥,-) 5/25/2019 Unit-1 Network Layer

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(¥,-) 5/25/2019 Unit-1 Network Layer

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(¥,-) 5/25/2019 Unit-1 Network Layer

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(¥,-) 5/25/2019 Unit-1 Network Layer

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(¥,-) 5/25/2019 Unit-1 Network Layer

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(¥,-) 5/25/2019 Unit-1 Network Layer

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(¥,-) 5/25/2019 Unit-1 Network Layer

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) 5/25/2019 Unit-1 Network Layer

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) 5/25/2019 Unit-1 Network Layer

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) 5/25/2019 Unit-1 Network Layer

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) 5/25/2019 Unit-1 Network Layer

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) 5/25/2019 Unit-1 Network Layer

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) 5/25/2019 Unit-1 Network Layer

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) 5/25/2019 Unit-1 Network Layer

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) 5/25/2019 Unit-1 Network Layer

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) 5/25/2019 Unit-1 Network Layer