Network Guide to Networks 5th Edition

1. Network+ Guide to Networks5th Edition Chapter 4 Introduction to TCP/IP Protocols

2. Network+ Guide to Networks, 5th Edition 2 Objectives Identify and explain the functions of the core TCP/IP protocols Explain how the TCP/IP protocols correlate to layers of the OSI model Discuss addressing schemes for TCP/IP in IPv4 and IPv6 protocols Describe the purpose and implementation of DNS (Domain Name System) and DHCP (Dynamic Host Configuration Protocol) Identify the well-known ports for key TCP/IP services Describe common Application layer TCP/IP protocols

3. Network+ Guide to Networks, 5th Edition 3 Characteristics of TCP/IP (Transmission Control Protocol/ Internet Protocol) Protocol Suite “IP” or “TCP/IP” Subprotocols (TCP, IP, UDP, ARP, HTTP, etc.) Developed by Department of Defense ARPANET (1960s) Internet precursor

4. Network+ Guide to Networks, 5th Edition 4 Characteristics of TCP/IP (cont’d.) Popularity Low cost Communicates between dissimilar platforms Open nature Routable Spans more than one LAN (LAN segment) Flexible Runs on combinations of network operating systems or network media Disadvantage: requires more configuration

5. Network+ Guide to Networks, 5th Edition 5 TCP (Transmission Control Protocol) Transport layer protocol Provides reliable data delivery services Connection-oriented subprotocol Establish connection before transmitting Sequencing and checksums Flow control Data does not flood node TCP segment format Encapsulated by IP datagram in Network layer Becomes IP datagram’s “data”

6. Network+ Guide to Networks, 5th Edition 6 TCP (cont’d.)

7. Network+ Guide to Networks, 5th Edition 7 TCP Three-Way Handshake Before any data is exchanged. . . Host-A issues SYN message to Host-B Host-B receives message, sends ACK message to Host-A Host-A sends ACK to Host-B

8. Network+ Guide to Networks, 5th Edition 8

9. Network+ Guide to Networks, 5th Edition 9 UDP (User Datagram Protocol) Transport layer protocol Provides unreliable data delivery services Connectionless transport service No assurance packets received in correct sequence No guarantee packets received at all No error checking, sequencing Lacks sophistication More efficient than TCP Appropriate when great volume of data must be transferred quickly (streaming audio/video)

10. Network+ Guide to Networks, 5th Edition 10 UDP (cont’d.)

11. Network+ Guide to Networks, 5th Edition 11 IP (Internet Protocol) Network layer protocol How and where data delivered, including: Data’s source and destination addresses Enables TCP/IP to internetwork Traverse more than one network segment More than one network type through router Network layer data formed into packets IP datagram Data envelope Contains information for routers to transfer data between different network segments

12. Network+ Guide to Networks, 5th Edition 12 IP (cont’d.) Unreliable, connectionless protocol No guaranteed data delivery IP used by higher level protocols Ensure data packets delivered to correct addresses Reliability component Header checksum Verifies routing information integrity in IP header

13. Network+ Guide to Networks, 5th Edition 13 IP (cont’d.)

14. Network+ Guide to Networks, 5th Edition 14 ICMP (Internet Control Message Protocol) Network layer protocol Reports on data delivery success/failure Announces transmission failures to sender Network congestion Data fails to reach destination Data discarded: TTL expired ICMP cannot correct errors Provides critical network problem troubleshooting information

15. Network+ Guide to Networks, 5th Edition 15 ARP (Address Resolution Protocol) Network layer protocol Obtains host (node) MAC (physical) address Creates database Maps MAC address to host’s IP (logical) address ARP table (ARP cache) Database on computers hard disk Contains recognized MAC-to-IP address mappings Increases efficiency

16. Network+ Guide to Networks, 5th Edition 16 ARP (cont’d.)

17. Network+ Guide to Networks, 5th Edition 17 IPv4 Addressing Networks recognize two addresses Logical (Network layer) Physical (MAC, hardware) addresses IP protocol handles logical addressing Specific parameters Unique 32-bit number Divided into four octets (sets of eight bits) Separated by dots Example: 144.92.43.178

18. Network+ Guide to Networks, 5th Edition 18 IPv4 Addressing (cont’d.) Network Class determined by first octet Class A, Class B, Class C Class D, Class E rarely used (never assign)

19. Network+ Guide to Networks, 5th Edition 19 Running out of addresses IPv6 incorporates new addressing scheme

20. Network+ Guide to Networks, 5th Edition 20 IPv4 Addressing (cont’d.)

21. Network+ Guide to Networks, 5th Edition 21 Binary and Dotted Decimal Notation Decimal number between 0 and 255 represents each binary octet Dot (period) separates each decimal number 10.34.231.7 =  000010100010001011100111000001112

22. Network+ Guide to Networks, 5th Edition 22 Subnet Mask Identifies every device on TCP/IP-based network 32-bit number (net mask) Identifies device’s subnet Combines with device IP address Informs network about segment, network where device attached Four octets (32 bits) Expressed in binary or dotted decimal notation Assigned same way a IP addresses Manually, automatically (via DHCP)

23. Network+ Guide to Networks, 5th Edition 23 Subnetting Subdividing network single class into multiple, smaller logical networks (segments) Control network traffic Make best use of limited number of IP addresses Subnet mask varies depending on subnetting Nonsubnetted networks use defaults

24. Network+ Guide to Networks, 5th Edition 24 Assigning IP Addresses Government-sponsored organizations “dole out” IP addresses IANA ICANN RIRs Companies, individuals obtain IP addresses from ISPs Every network node must have unique IP address

25. Network+ Guide to Networks, 5th Edition 25 Assigning IP Addresses (cont’d.) Static IP address Assignment done manually by modifying client-PC’s TCP/IP properties Human error cause duplicates Automatic IP addressing with DHCP reduces duplication and other errors

26. Network+ Guide to Networks, 5th Edition 26 DHCP Leasing Process (cont’d.)

27. Network+ Guide to Networks, 5th Edition 27 IPv6 Addressing Gradually replacing IPv4 IPv6 supported by most new applications, servers, network devices Implementation has been delayed due to: Cost of upgrading infrastructure NAT

28. IPv6 Advantages More efficient header Better security Better prioritization provisions, Automatic IP address configuration And most importantly. . .billions of additional IP addresses

29. Network+ Guide to Networks, 5th Edition 29 Ports and Sockets Port numbers Simplify TCP/IP communications Ensures data transmitted correctly Processes assigned unique port numbers Example Telnet port number: 23 IPv4 host address: 10.43.3.87 Socket address: 10.43.3.87:23 Port number + IP address = socket

30. Network+ Guide to Networks, 5th Edition 30 Ports and Sockets(cont’d.)

31. Network+ Guide to Networks, 5th Edition 31 Ports and Sockets (cont’d.) Port number range: 0 to 65535 Three types Well Known Ports Range: 0 to 1023 Operating system or administrator use Registered Ports Range: 1024 to 49151 Network users, processes with no special privileges Dynamic and/or Private Ports Range: 49152 through 65535 No restrictions

32. Host Files Computers think in binary. People don’t. ARPAnet used HOSTS.TXT file Associated host names with IP addresses Host matched by one line Identifies host’s name, IP address Alias provides nickname Current operating systems still use this file for limited purposes.

33. Network+ Guide to Networks, 5th Edition 33 Host Names and DNS (Domain Name System) Host -- Internet device Host name -- Name describing device Domain -- group of hosts belonging to same organization Domain name -- identifies domain (loc.gov) Fully qualified name = host name + domain name(jasmine.loc.gov)

34. Network+ Guide to Networks, 5th Edition 34

35. Network+ Guide to Networks, 5th Edition 35 DNS (Domain Name System) Hierarchical system of databases making name-to-address association possible DNS components Clients -- Any hosts on Internet needing to look up domain name information DNS servers -- provide information to resolvers on request Namespace -- Abstract database of Internet IP addresses, associated names

36. Network+ Guide to Networks, 5th Edition 36 DNS (cont’d.) DNS redundancy Hundreds/thousands of DNS servers across globe related in hierarchical manner Servers synchronize with one another 13 “root servers” (ultimate authorities)

37. Network+ Guide to Networks, 5th Edition 37 Application Layer Protocols HTTP (web traffic) SMTP (e-mail) FTP (file tranfer) DHCP (automatic address assignment) Telnet (terminal emulation)NTP (time synchronization) Many additional Application layer protocols exist

38. Network+ Guide to Networks, 5th Edition 38 PING (Packet Internet Groper) Provides verification TCP/IP installed, bound to NIC, configured correctly, communicating with network Host responding Uses ICMP services Send echo request and echo reply messages Determine IP address validity Ping IP address or host name Ping loopback address: 127.0.0.1 Determine if workstation’s TCP/IP services running

39. Network+ Guide to Networks, 5th Edition 39 Operating system determines Ping command options, switches, syntax PING (cont’d.)