1. 1 Introduction to Networking Dr. Mahdi Nasereddin PPU

2. 2 Introduction  Web Browser, e-mail, streaming audio, etc..  The Web browser http://www.google.com 17 messages!!! 6 messages to translate www.google.com into an IP addresswww.google.com 3 messages to establish a TCP connection 4 messages used by HTTP to send a get request 4 messages to tear down the TCP connection

3. 3 The Basics  Internetworking: Communication between two or more networks via a router or gateway.  Hub?  Switches?  Routers?

4. 4 Hubs, Switches, and Routers  Routers They are used to separate different networks Main function: to route packets across networks Deal with global addresses “IP addresses”  Hubs Multi-port repeaters  Switches Used within a network Smarter than hubs Deal with local addresses “Hardware or Mac Addresses”

5. 5 Media  10Base2  10Base5  10BaseT  100BaseTX  1000BaseT  1000BaseSX  1000BaseLX

6. 6 Ethernet Cabling (Straight-Through Cable)  Recommended use: Switch to router Switch/Hub to Computer

7. 7 Ethernet Cabling (Crossover Cable)  Recommended use Switch/hub to Switch/hub Router to router PC to PC Router to PC

8. 8 Ethernet Cabling (Rolled Cable)  Recommended use: Computer to console port of a switch or router

9. 9 Network Architecture  Peer to Peer  Server based

10. 10 Typical Networks 12

11. 11 Topologies  Bus  Ring  Star  Mesh  Star-Bus

12. 12 Bus Topology 18

13. 13 Simple Star Network 24

14. 14 Simple Ring Network 25

15. 15 Mesh Topology 27

16. 16 Star-Bus Topology 29

17. 17 Performance  How do we measure network performance? Bandwidth (Throughput) Number of bits that can be transmitted over a certain period of time (Ex. 10 Mbps) Latency (Delay) How long it takes a message to travel from one end of the network to the other (Measured is Seconds) RTT Latency = Propagation + Transmit + Queue –Propagation = Distance/Speed of light –Transmit = Size/Bandwidth

18. 18 Beyond the basics: The Layered Approach  Makes complex systems easier to understand  In networking, there are two approaches: OSI The TCP/IP model

19. 19 The TCP/IP Model

20. 20 Process/Application Layer Protocols  Telnet “Virtual terminal”  File Transfer Protocol “FTP”  Trivial File Transfer Protocol “TFTP”  Network File System “NFS”  Simple Mail Transfer Protocol “SMTP”  Line Printer Daemon “LPD”  X Windows  Simple Network Management Protocol “SNMP”  Domain Name Service “DNS”  Dynamic Host Configuration Protocol “DHCP”

21. 21 Host to Host Layer Protocols  Transmission Control Protocol “TCP”  User Datagram Protocol “UDP”

22. 22 TCP versus UDP TCPUDP SequencedNot sequenced ReliableNot reliable Virtual circuitLow overhead Windowing flow controlNo flow control

23. 23 Port Numbers  Used by TCP and UDP to communicate with upper layers keep track if different conversations crossing the network simultaneously  Sender port number start at 1024

24. 24 Port Numbers to remember PortApplication 21ftp 23telnet 53DNS 69TFTP 110POP3 80HTTP

25. 25 Internet Layer Protocols  Internet Protocol “IP”  IP Address: 192.168.0.1 Like a home address for the post office  Network Address: 192.168.0.0/24 Like a ZIP/Postal code for the post office Denotes a range of addresses  Format ‘Dotted-Quad’ notation: xxx.yyy.zzz.aaa Each dotted component is an 8-bit number Range is 0.0.0.0 to 255.255.255.255 The prefix length (/24), is the number of significant bits in a network

26. 26 Addressing  Class A (N.H.H.H) 1-126  Class B (N.N.H.H) 128-191  Class C (N.N.N.H) 192-223

27. 27 Practice Makes Perfect  What class does the following IPs belong to? 132.25.23.12 13.25.1.1 200.20.3.6 254.23.1.14

28. 28 Reserved IPs  All 0s for the host address  Network address Example: 132.12.0.0  All 1s for the host address  Broadcast address Example: 132.12.255.255  127.0.0.1  local node  All 0s for the Network address  This network Example: 0.0.12.1 (If I am on network 169.23.0.0 then this is the same as my IP address 169.23.12.1)  All 1s for the Network address  All networks with this host address

29. 29 Subnet Mask  Subnet Mask tells you what bits belong to host id and what bits belong to network id  Why were they created?

30. 30 NAT and PAT?  Network Address Translation  Port Address Translation

31. 31 Protocol: IPv6  Internet Protocol, Version 6 RFC 2460  Advantages over IPv4 More native security Increases available address space from 32 bits to 128 bits Easily extensible  Disadvantages IPv4 is everywhere (cannot be replaced overnight) More protocol overhead (addresses are now 16 bytes instead of 4) IP routing protocols must be reworked to support it