Chapter04 -- network protocols


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Chapter04 -- network protocols

  1. 1. Chapter 4: Network Protocols Network+ Guide to Networks
  2. 2. Objectives <ul><li>Identify the characteristics of TCP/IP, IPX/SPX, NetBIOS, and AppleTalk </li></ul><ul><li>Understand how key network protocols correlate to layers of the OSI Model </li></ul><ul><li>Identify the core protocols of the TCP/IP suite and describe their functions </li></ul>
  3. 3. Objectives (continued) <ul><li>Understand the most popular protocol addressing schemes </li></ul><ul><li>Describe the purpose and implementation of the domain name system </li></ul><ul><li>Install protocols on Windows XP clients </li></ul>
  4. 4. Introduction To Protocols <ul><li>Protocol is a rule that governs how networks communicate </li></ul><ul><ul><li>Define the standards for communication between network devices </li></ul></ul><ul><ul><li>Vary according to their speed, transmission efficiency, utilization of resources, ease of setup, compatibility, and ability to travel between different LANs </li></ul></ul>
  5. 5. Introduction To Protocols <ul><ul><li>Networks running more than one protocol are called multiprotocol networks </li></ul></ul>
  6. 6. Transmission Control Protocol /Internet Protocol (TCP/IP) <ul><ul><li>TCP/IP is not simply one protocol, but rather a suite of specialized protocols—including TCP, IP, UDP, ARP, and many others—called sub protocols </li></ul></ul><ul><ul><li>Extremely popular because of low cost </li></ul></ul>
  7. 7. TCP/IP (continued) <ul><ul><li>Has ability to communicate between a multitude of dissimilar platforms </li></ul></ul><ul><ul><li>The core protocols are free and their code is available for anyone to read or modify </li></ul></ul><ul><ul><li>Its routable, because they carry Network layer addressing information that can be interpreted by a router </li></ul></ul>
  8. 8. <ul><ul><li>Has flexibility because it can run on virtually any combination of network operating systems or network media </li></ul></ul><ul><li>TCP/IP Compared to the OSI Model </li></ul><ul><ul><li>The TCP/IP suite of protocols can be divided into four layers that roughly correspond to the seven layers of the OSI Model </li></ul></ul>TCP/IP (continued)
  9. 9. <ul><li>TCP/IP Compared to the OSI Model (continued) </li></ul><ul><ul><li>Application layer </li></ul></ul><ul><ul><ul><li>Applications gain access to the network through this layer, via protocols </li></ul></ul></ul><ul><ul><li>Transport layer </li></ul></ul><ul><ul><ul><li>Holds the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP), which provide flow control, error checking, and sequencing </li></ul></ul></ul>TCP/IP (continued)
  10. 10. <ul><li>TCP/IP Compared to the OSI Model (continued) </li></ul><ul><ul><li>Internet layer </li></ul></ul><ul><ul><ul><li>Holds the Internet Protocol (IP), Internet Control Message Protocol (ICMP), and Address Resolution Protocol (ARP).These protocols handle message routing, error reporting, delivery confirmation, and logical addressing </li></ul></ul></ul><ul><ul><li>Network Interface Layer </li></ul></ul><ul><ul><ul><li>This layer handles the formatting of data and transmission to the network wire </li></ul></ul></ul>TCP/IP (continued)
  11. 11. <ul><li>The TCP/IP Core Protocols </li></ul><ul><ul><li>Certain sub protocols of the TCP/IP suite </li></ul></ul><ul><ul><li>Operate in the Transport or Network layers of the OSI Model </li></ul></ul>TCP/IP (continued)
  12. 12. <ul><li>Transmission Control Protocol (TCP) </li></ul><ul><ul><li>Operates in the Transport layer of both the OSI and the TCP/IP Models and provides reliable data delivery services </li></ul></ul><ul><ul><li>TCP is a connection-oriented sub protocol </li></ul></ul>TCP/IP (continued)
  13. 13. <ul><li>Fields belonging to a TCP segment are described in the following list: </li></ul><ul><ul><li>Source port </li></ul></ul><ul><ul><li>Destination port </li></ul></ul><ul><ul><li>Sequence number </li></ul></ul>TCP/IP (continued)
  14. 14. <ul><ul><li>Acknowledgment number (ACK) </li></ul></ul><ul><ul><li>TCP header length </li></ul></ul><ul><ul><li>Reserved </li></ul></ul><ul><ul><li>Flags </li></ul></ul><ul><ul><li>Sliding-window size (or window) </li></ul></ul>TCP/IP (continued)
  15. 15. <ul><ul><li>Checksum - Allows the receiving node to determine whether the TCP segment became corrupted during transmission </li></ul></ul><ul><ul><li>Urgent pointer - Indicate a location in the data field </li></ul></ul><ul><ul><li>Options - Used to specify special options </li></ul></ul>TCP/IP (continued)
  16. 16. <ul><ul><li>Padding - Contains filler information to ensure that the size of the TCP header is a multiple of 32 bits </li></ul></ul><ul><ul><li>Data - Contains data originally sent by the source node and the size of the Data field depends on how much data needs to be transmitted </li></ul></ul>TCP/IP (continued)
  17. 17. <ul><li>User Datagram Protocol (UDP) </li></ul><ul><ul><li>A connectionless transport service </li></ul></ul><ul><ul><li>UDP offers no assurance that packets will be received in the correct sequence </li></ul></ul>TCP/IP (continued)
  18. 18. <ul><li>User Datagram Protocol (UDP) </li></ul><ul><ul><li>Provides no error checking or sequencing </li></ul></ul><ul><ul><li>More efficient for carrying messages that fit within one data packet </li></ul></ul>TCP/IP (continued)
  19. 19. <ul><li>Internet Protocol (IP) </li></ul><ul><ul><li>Provides information about how and where data should be delivered, including the data’s source and destination addresses </li></ul></ul><ul><ul><li>IP is the sub protocol that enables TCP/IP to internetwork </li></ul></ul>TCP/IP (continued)
  20. 20. <ul><li>Internet Protocol (IP) </li></ul><ul><ul><li>IP datagram acts as an envelope for data and contains information necessary for routers to transfer data between different LAN segments </li></ul></ul><ul><ul><li>IP is an unreliable, connectionless protocol, which means that it does not guarantee delivery of data </li></ul></ul>TCP/IP (continued)
  21. 21. <ul><li>Internet Control Message Protocol (ICMP) </li></ul><ul><ul><li>An Internet layer protocol that reports on the success or failure of data delivery </li></ul></ul><ul><ul><li>ICMP announcements provide critical information for troubleshooting network problems </li></ul></ul>TCP/IP (continued)
  22. 22. <ul><li>Address Resolution Protocol (ARP) </li></ul><ul><ul><li>An Internet layer protocol that obtains the MAC (physical) address of a host, or node, then creates a database that maps the MAC address to the host’s IP (logical) address </li></ul></ul>TCP/IP (continued)
  23. 23. <ul><li>Address Resolution Protocol (ARP) table </li></ul><ul><ul><li>Dynamic ARP table entries are created when a client makes an ARP request that cannot be satisfied by data already in the ARP table </li></ul></ul><ul><ul><li>Static ARP table entries are those that someone has entered manually using the ARP utility </li></ul></ul><ul><ul><li>ARP can be a valuable troubleshooting tool </li></ul></ul>TCP/IP (continued)
  24. 24. <ul><li>Reverse Address Resolution Protocol (RARP) </li></ul><ul><ul><li>Allow the client to send a broadcast message with its MAC address and receive an IP address in reply </li></ul></ul><ul><ul><li>RARP was originally developed as a means for diskless workstations </li></ul></ul>TCP/IP (continued)
  25. 25. <ul><li>Addressing in TCP/IP </li></ul><ul><ul><li>Two kinds of addresses: Logical or physical </li></ul></ul>TCP/IP (continued)
  26. 26. <ul><ul><li>Logical (or Network layer) can be manually or automatically assigned and must follow rules set by the protocol standards </li></ul></ul><ul><ul><li>Physical (or MAC, or hardware) addresses are assigned to a device’s network interface card at the factory by its manufacturer </li></ul></ul><ul><ul><li>Addresses on TCP/IP-based networks are often called IP addresses </li></ul></ul>TCP/IP (continued)
  27. 27. <ul><ul><li>IP addresses are assigned and used according to very specific parameters </li></ul></ul><ul><ul><ul><li>Each IP address is a unique 32-bit number, divided into four octets, or sets of 8-bits, that are separated by periods </li></ul></ul></ul><ul><ul><ul><li>An IP address contains two types of information: network and host </li></ul></ul></ul><ul><ul><ul><li>From the first octet you can determine the network class </li></ul></ul></ul><ul><ul><ul><li>Three types of network classes are used on modern LANs: Class A, Class B, and Class C </li></ul></ul></ul>TCP/IP (continued)
  28. 28. <ul><ul><li>IP Addresses specific parameters continued </li></ul></ul><ul><ul><ul><li>Class D and Class E addresses do exist, but are rarely used </li></ul></ul></ul><ul><ul><ul><li>Class D addresses are reserved for a special type of transmission called multicasting </li></ul></ul></ul><ul><ul><ul><ul><li>Multicasting allows one device to send data to a specific group of devices </li></ul></ul></ul></ul>TCP/IP (continued)
  29. 29. <ul><ul><li>IP Addresses specific parameters continued </li></ul></ul><ul><ul><ul><li>Some IP addresses are reserved for special functions, like broadcasts, and cannot be assigned to machines or devices </li></ul></ul></ul><ul><ul><ul><li>127 is not a valid first octet for any IP address </li></ul></ul></ul><ul><ul><ul><li>The range of addresses beginning with 127 is reserved for a device communicating with itself, or performing loopback communication </li></ul></ul></ul>TCP/IP (continued)
  30. 30. <ul><li>The command used to view IP information on a Windows XP workstation is ipconfig </li></ul>TCP/IP (continued)
  31. 31. <ul><li>Binary and Dotted Decimal Notation </li></ul><ul><ul><li>A decimal number between 0 and 255 represents each binary octet (for a total of 256 possibilities) </li></ul></ul><ul><ul><li>The binary system is the way that computers interpret IP addresses </li></ul></ul><ul><ul><li>In this system every piece of information is represented by 1s and 0s and each 1 or 0 constitutes a bit </li></ul></ul>TCP/IP (continued)
  32. 32. <ul><li>Subnet Mask </li></ul><ul><ul><li>A special 32-bit number that, when combined with a device’s IP address, informs the rest of the network about the segment or network to which the device is attached </li></ul></ul><ul><ul><li>A more common term for subnet mask is net mask, and sometimes simply mask </li></ul></ul><ul><ul><li>Subnetting is a process of subdividing a single class of network into multiple, smaller logical networks, or segments </li></ul></ul>TCP/IP (continued)
  33. 33. <ul><li>Assigning IP Addresses </li></ul><ul><ul><li>Every node on a network must have a unique IP address </li></ul></ul><ul><ul><li>If you add a node to a network and its IP address is already in use by another node on the same subnet, an error message will be generated on the new client </li></ul></ul>TCP/IP (continued)
  34. 34. <ul><ul><li>A manually assigned IP address is called a static IP address </li></ul></ul><ul><ul><li>Most network administrators rely on a network service to automatically assign them </li></ul></ul>TCP/IP (continued)
  35. 35. <ul><li>Two methods of automatic IP addressing: BOOTP and DHCP </li></ul><ul><ul><li>Bootstrap Protocol (BOOTP), an Application layer protocol, uses a central list of IP addresses and their associated devices’ MAC addresses to assign IP addresses to clients dynamically </li></ul></ul>TCP/IP (continued)
  36. 36. <ul><ul><ul><li>An IP address that is assigned to a device upon request and is changeable is known as a dynamic IP address </li></ul></ul></ul><ul><ul><ul><li>BOOTP has the potential to issue additional information, such as the client’s subnet mask and requires administrators to enter every IP and MAC address manually into the BOOTP table </li></ul></ul></ul>TCP/IP (continued)
  37. 37. <ul><ul><li>Dynamic Host Configuration Protocol (DHCP) </li></ul></ul><ul><ul><ul><li>An automated means of assigning a unique IP address to every device on a network </li></ul></ul></ul><ul><ul><ul><li>DHCP does not require a table of IP and MAC addresses on the server </li></ul></ul></ul><ul><ul><ul><li>DHCP does require configuration of DHCP service on a DHCP server </li></ul></ul></ul>TCP/IP (continued)
  38. 38. <ul><li>Terminating a DHCP Lease </li></ul><ul><ul><li>A DHCP lease may expire based on the period established for it in the server configuration or it may be manually terminated </li></ul></ul><ul><li>Sockets and Ports </li></ul><ul><ul><li>Every process on a machine is assigned a port number and the process’s port number plus its host machine’s IP address equals the process’s socket </li></ul></ul><ul><ul><li>The use of port numbers simplifies TCP/IP communications and ensures that data are transmitted to the correct application </li></ul></ul>TCP/IP (continued)
  39. 39. <ul><ul><li>Port numbers range from 0 to 65,539 and are divided by IANA into three types: Well Known Ports, Registered Ports, and Dynamic and/or Private Ports </li></ul></ul><ul><ul><li>Well Known Ports are in the range of 0 to 1023 and are assigned to processes that only the operating system or an Administrator of the system can access </li></ul></ul>TCP/IP (continued)
  40. 40. <ul><ul><li>Registered Ports are in the range of 1024 to 49151. These ports are accessible to network users and processes that do not have special administrative privileges </li></ul></ul><ul><ul><li>Dynamic and/or Private Ports are those from 49152 through 65535 and are open for use without restriction </li></ul></ul>TCP/IP (continued)
  41. 41. <ul><li>Addressing in IPv6 </li></ul><ul><ul><li>Known as IP next generation, or Ipng is slated to replace the current IP protocol, IPv4 </li></ul></ul><ul><ul><li>IPv6 offers several advantages over IPv4, including a more efficient header, better security, better prioritization allowances, and automatic IP address configuration </li></ul></ul><ul><ul><li>The most valuable advantage IPv6 offers is its promise of billions and billions of additional IP addresses through its new addressing scheme </li></ul></ul>TCP/IP (continued)
  42. 42. <ul><li>Addressing in IPv6 (continued) </li></ul><ul><ul><li>The most notable difference between IP addresses in IPv4 and IPv6 is their size </li></ul></ul><ul><ul><ul><li>IPv4 addresses are composed of 32 bits, IPv6 are eight 16-bit fields and total 128 bits </li></ul></ul></ul><ul><ul><ul><li>IPv4 address contains binary numbers separated by a period, each field in an IPv6 address contains hexadecimal numbers separated by a colon </li></ul></ul></ul>TCP/IP (continued)
  43. 43. <ul><li>Host Names and Domain Name System (DNS) every device on the Internet is technically known as a host and every host can take a host name </li></ul>TCP/IP (continued)
  44. 44. <ul><li>Domain Names every host is a member of a domain, or a group of computers that belong to the same organization and have part of their IP addresses in common </li></ul><ul><ul><li>A domain name is associated with a company or other type of organization </li></ul></ul><ul><ul><li>Local host name plus its domain name is a fully qualified host name </li></ul></ul>TCP/IP (continued)
  45. 45. <ul><ul><li>A domain name is represented by a series of character strings, called labels, separated by dots </li></ul></ul><ul><ul><ul><li>Each label represents a level in the domain naming hierarchy </li></ul></ul></ul><ul><ul><ul><ul><li>In the domain name,, “com” is the top-level domain (TLD), “novell” is the second-level domain, and “www” is the third-level domain </li></ul></ul></ul></ul><ul><ul><ul><li>Domain names must be registered with an Internet naming authority that works on behalf of ICANN </li></ul></ul></ul>TCP/IP (continued)
  46. 46. <ul><li>Domain Name System (DNS) </li></ul><ul><ul><li>A hierarchical way of associating domain names with IP addresses </li></ul></ul><ul><ul><li>“ DNS” refers to both the Application-layer service and the organized system of computers and databases </li></ul></ul>TCP/IP (continued)
  47. 47. <ul><ul><li>The DNS service does not rely on one file or even one server, but rather on many computers across the globe </li></ul></ul><ul><ul><ul><li>These computers are related in a hierarchical manner, with thirteen computers, known as root servers, acting as the ultimate authorities </li></ul></ul></ul>TCP/IP (continued)
  48. 48. <ul><ul><li>DNS service is divided into three components: resolvers, name servers, and name space </li></ul></ul><ul><ul><li>Resolvers are any hosts on the Internet that need to look up domain name information </li></ul></ul>TCP/IP (continued)
  49. 49. <ul><ul><li>Name servers (or DNS servers) are servers that contain databases of associated names and IP addresses and provide this information to resolvers on request </li></ul></ul><ul><ul><li>The term name space refers to the database of Internet IP addresses and their associated names </li></ul></ul>TCP/IP (continued)
  50. 50. <ul><ul><li>Resource record is a single record that describes one piece of information in the DNS database </li></ul></ul><ul><ul><ul><li>An address resource record is a type of resource record that maps the IP address of an Internet-connected device to its domain name </li></ul></ul></ul><ul><ul><ul><li>Approximately 20 types of resource records are currently used </li></ul></ul></ul>TCP/IP (continued)
  51. 51. <ul><li>Some TCP/IP Application Layer Protocols </li></ul><ul><ul><li>Telnet </li></ul></ul><ul><ul><ul><li>A terminal emulation protocol used to log on to remote hosts using the TCP/IP protocol suite </li></ul></ul></ul><ul><ul><ul><li>Using Telnet, a TCP connection is established and keystrokes on the user’s machine act like keystrokes on the remotely connected machine </li></ul></ul></ul><ul><ul><ul><li>Telnet is notoriously insecure </li></ul></ul></ul>TCP/IP (continued)
  52. 52. <ul><li>Some TCP/IP Application Layer Protocols (continued) </li></ul><ul><ul><li>File Transfer Protocol (FTP) </li></ul></ul><ul><ul><ul><li>Used to send and receive files via TCP/IP </li></ul></ul></ul><ul><ul><ul><li>FTP commands will work from your operating system’s command prompt </li></ul></ul></ul><ul><ul><ul><li>Many FTP hosts accept anonymous logins </li></ul></ul></ul>TCP/IP (continued)
  53. 53. <ul><ul><li>Trivial File Transfer Protocol (TFTP) </li></ul></ul><ul><ul><ul><li>Enables file transfers between computers, but it is simpler (or more trivial) than FTP </li></ul></ul></ul><ul><ul><ul><li>TFTP relies on UDP at the Transport layer </li></ul></ul></ul><ul><ul><ul><li>TFTP is useful when you need to load data or programs on a diskless workstation </li></ul></ul></ul><ul><ul><ul><li>TFTP does not require a user to log on to a host </li></ul></ul></ul>TCP/IP (continued)
  54. 54. <ul><ul><li>Network Time Protocol (NTP) </li></ul></ul><ul><ul><ul><li>Used to synchronize the clocks of computers on a network </li></ul></ul></ul><ul><ul><ul><li>NTP depends on UDP for Transport layer services </li></ul></ul></ul><ul><ul><ul><li>NTP is a protocol that benefits from UDP’s quick, connectionless nature at the Transport layer </li></ul></ul></ul><ul><ul><ul><li>NTP is time-sensitive and cannot wait for the error checking that TCP would require </li></ul></ul></ul>TCP/IP (continued)
  55. 55. <ul><ul><li>Packet Internet Groper (PING) </li></ul></ul><ul><ul><ul><li>A utility that can verify that TCP/IP is installed, bound to the NIC, configured correctly, and communicating with the network </li></ul></ul></ul><ul><ul><ul><li>PING uses ICMP services to send echo request and echo reply messages that determine the validity of an IP address </li></ul></ul></ul><ul><ul><ul><li>By pinging the loopback address,, you can determine whether your workstation’s TCP/IP services are running </li></ul></ul></ul>TCP/IP (continued)
  56. 56. <ul><ul><li>Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX) is a protocol originally developed by Xerox </li></ul></ul><ul><ul><li>Modified and adopted by Novell in the1980s for its NetWare network operating system </li></ul></ul><ul><ul><li>Microsoft’s implementation of IPX/SPX is called NWLink </li></ul></ul>IPX/SPX
  57. 57. <ul><li>The IPX and SPX Protocols </li></ul><ul><ul><li>Internetwork Packet Exchange (IPX) operates at the Network layer of the OSI Model and provides logical addressing and internetworking services, similar to IP in the TCP/IP suite </li></ul></ul><ul><ul><ul><li>IPX is a connectionless service because it does not require a session to be established before it transmits, and it does not guarantee that data will be delivered in sequence or without errors </li></ul></ul></ul>IPX/SPX (continued)
  58. 58. <ul><ul><li>Sequenced Packet Exchange (SPX) belongs to the Transport layer of the OSI Model </li></ul></ul><ul><ul><ul><li>A connection-oriented protocol and therefore must verify that a session has been established with the destination node before it will transmit data </li></ul></ul></ul>IPX/SPX (continued)
  59. 59. <ul><li>Addressing in IPX/SPX </li></ul><ul><ul><li>IPX/SPX-based networks require that each node on a network be assigned a unique address to avoid communication conflicts </li></ul></ul><ul><ul><li>IPX is the component of the protocol that handles addressing, addresses on an IPX/SPX network are called IPX addresses </li></ul></ul><ul><ul><li>IPX addresses contain two parts: the network address and the node address </li></ul></ul>IPX/SPX (continued)
  60. 60. NetBIOS and NetBEUI <ul><ul><li>NetBIOS (Network Basic Input Output System) is a protocol originally designed for IBM to provide Transport and Session layer services for applications running on small, homogenous networks </li></ul></ul><ul><ul><li>NetBEUI can support only 254 connections, however, and does not allow for good security </li></ul></ul><ul><ul><ul><li>Because NetBEUI frames include only Data Link layer (or MAC) addresses and not Network layer addresses, it is not routable </li></ul></ul></ul>
  61. 61. <ul><li>Windows Internet Naming Service (WINS) - Provides a means of resolving NetBIOS names to IP addresses </li></ul><ul><ul><li>A computer’s NetBIOS name and its TCP/IP host name are different entities, though you can have the same name for both </li></ul></ul>NetBIOS and NetBEUI (continued)
  62. 62. <ul><ul><li>WINS has the same relationship to NetBIOS as DNS has to TCP/IP </li></ul></ul><ul><ul><li>WINS does not assign names or IP addresses, but merely keeps track of which NetBIOS names are linked to which IP addresses </li></ul></ul>NetBIOS and NetBEUI (continued)
  63. 63. <ul><ul><li>The protocol suite originally designed to interconnect Macintosh computers </li></ul></ul><ul><ul><li>An AppleTalk network is separated into logical groups of computers called AppleTalk zones </li></ul></ul>Appletalk
  64. 64. <ul><ul><li>An AppleTalk node ID is a unique 8-bit or 16-bit number that identifies a computer on an AppleTalk network </li></ul></ul><ul><ul><li>An AppleTalk network number is a unique 16-bit number that identifies the network to which a node is connected </li></ul></ul>Appletalk (continued)
  65. 65. <ul><ul><li>Binding is the process of assigning one network component to work with another </li></ul></ul><ul><ul><li>You can manually bind protocols that are not already associated with a network interface </li></ul></ul>Binding Protocols on a Windows XP Workstation
  66. 66. Summary <ul><li>Characteristics of TCP/IP, IPX/SPX, NetBIOS, and AppleTalk </li></ul><ul><li>Network protocols correlate to layers of the OSI Model </li></ul><ul><li>Core protocols of the TCP/IP suite and their functions </li></ul>
  67. 67. Summary (continued) <ul><li>The most popular protocol addressing schemes </li></ul><ul><li>Purpose and implementation of the domain name system </li></ul><ul><li>Install protocols on Windows XP clients </li></ul>