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S305 – Network Infrastructure Chapter 5 Network and Transport Layers.

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Presentation on theme: "S305 – Network Infrastructure Chapter 5 Network and Transport Layers."— Presentation transcript:

1 S305 – Network Infrastructure Chapter 5 Network and Transport Layers

2 Chapter 5 Outline Transport & Network Layer Protocols  TCP/IP Transport Layer Functions  Linking to the Application Layer  Segmenting  Session management Addressing  Assigning addresses and address resolution Routing  Types of routing, routing protocols, and multicasting TCP/IP Examples Copyright 2010 John Wiley & Sons, Inc

3 Network Layer Computer 1Computer 2

4 5.4.2 Dynamic Routing Algorithms Distance Vector  Uses the least number of hops to decide how to route a packet Link State  Uses a variety of information types to decide how to route a packet (more sophisticated) e.g., number of hops, congestion, speed of circuit  Links state info exchanged periodically by each node to keep every node in the network up to date  Provides more reliable, up to date paths to destinations 5 - 4

5 5.4.2.1 Routing Information Protocol (RIP) A dynamic distance vector interior routing protocol Operations:  Manager builds a routing table by using RIP  Routing tables broadcast periodically (every minute or so) by all nodes  When a new node added, RIP counts number of hops between computers and updates routing tables 5 - 5

6 5.4.2.1 Open Shortest Path First (OSPF) A dynamic link state interior routing protocol Became more popular on Internet  More reliable paths  Less burdensome to the network 5 - 6

7 5.5.1 Sending Messages using TCP/IP Required Network layer addressing information 1. 2. 3. 4. Address information is obtained from a configuration file or provided by a DHCP server What additional information is needed for servers? 5 - 7

8 5 - 8 5.5.1 TCP/IP Configuration Information

9 5.5.1 Subnet Masks Tells the computer what part of an Internet Protocol address to be used to determine whether the destination is on the same subnet or on a different subnet Example  Subnet: 149.61.10.x  Subnet mask: 255.255.255.000 Example  Subnets: 149.61.10.1-128,  Subnet mask 255.255.255.128 5 - 9

10 5.5.1 TCP/IP Network Example 5 - 10

11 5 - 11 5.5.1 Moving Messages - TCP/IP and Layers How layers are handled in a LAN: Host Computers Packets move through all layers  Gateways, Routers Packet moves from Physical layer to Data Link Layer through the network Layer At each stop along the way (e.g. from router to router):  Ethernet packets is removed and a new one is created for the next node  IP and above packets never change in transit (created by the original sender and destroyed by the final receiver)

12 5.5.1 Message Moving Through Layers 5 - 12

13 5.5.2 Known IP Address Transmit from A => E (A knows E’s IP Address) How many Hops will it take? 5 - 13 PATHIP Source IP Destination Ethernet Source Ethernet Destination

14 5.5.3 Unknown IP Address Transmit from A => E (A doesn’t know E’s IP address) How do we do this? 5 - 14 PATHIP Source IP Destination Ethernet Source Ethernet Destination DNS Request PATHIP Source IP Destination Ethernet Source Ethernet Destination DNS Response

15 5.5.4 Unknown Data Link Address Transmit from A => E (doesn’t know E’s Ethernet address) An ARP request from D will occur once the message sent by A is received by D. 5 - 15 PATHIP Source IP Destination Ethernet Source Ethernet Destination

16 5 - 16 5.5.2 Known IP Address and Ethernet Address Transmit from B => F (B knows F’s IP Address) PATHIP Source IP Destination Ethernet Source Ethernet Destination

17 5 - 17 5.5.3 Unknown IP Address Transmit from B => F (B doesn’t know F’s IP address) PATHIP Source IP Destination Ethernet Source Ethernet Destination

18 5 - 18 5.5.4 Unknown Ethernet Address Transmit from B => F (doesn’t know F’s Ethernet address) PATHIP Source IP Destination Ethernet Source Ethernet Destination

19 Implications for Management Most organizations moving toward a single standard based on TCP/IP  Decreased cost of buying and maintaining network equipment  Decreased cost of training networking staff Telephone companies with non-TCP/IP networks are also moving toward TCP/IP  Significant financial implications for telcos  Significant financial implications for networking equipment manufacturers 5 - 19


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