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Wxes2106 4

  1. 1. WXES2106 Network Technology Semester 1 2004/2005 Chapter 4 TCP/IP CCNA1: Module 9, 10.3 and 11
  2. 2. Contents <ul><li>Introduction </li></ul><ul><li>Internet Address </li></ul><ul><li>Obtaining an IP Address </li></ul><ul><li>Introduction to Subnetting </li></ul><ul><li>TCP/IP Transport Layer </li></ul><ul><li>Application Layer </li></ul>
  3. 3. Introduction <ul><li>The design of TCP/IP is ideal for the decentralized and robust network that is the Internet. </li></ul><ul><li>The TCP/IP model has four layers: the application layer, transport layer, Internet layer, and the network access layer. </li></ul><ul><li>The application layer of the TCP/IP model handles high-level protocols, issues of representation, encoding, and dialog control </li></ul>
  4. 4. Introduction <ul><li>TCP Applications </li></ul><ul><ul><li>File Transfer Protocol (FTP) </li></ul></ul><ul><ul><li>Trivial File Transfer Protocol (TFTP) </li></ul></ul><ul><ul><li>Network File System (NFS) </li></ul></ul><ul><ul><li>Simple Mail Transfer Protocol (SMTP) </li></ul></ul><ul><ul><li>Terminal emulation (Telnet) </li></ul></ul><ul><ul><li>Simple Network Management Protocol (SNMP) </li></ul></ul><ul><ul><li>Domain Name System (DNS) </li></ul></ul>
  5. 5. Introduction <ul><li>The transport layer provides transport services from the source host to the destination host. </li></ul><ul><li>TCP and UDP </li></ul><ul><ul><li>Segmenting upper-layer application data </li></ul></ul><ul><ul><li>Sending segments from one end device to another end device </li></ul></ul><ul><li>TCP only </li></ul><ul><ul><li>Establishing end-to-end operations </li></ul></ul><ul><ul><li>Flow control provided by sliding windows </li></ul></ul><ul><ul><li>Reliability provided by sequence numbers and acknowledgments </li></ul></ul>
  6. 6. Introduction <ul><li>The purpose of the Internet layer is to select the best path through the network for packets to travel. </li></ul><ul><li>Internet Protocol (IP) </li></ul><ul><ul><li>provides connectionless, best-effort delivery routing of packets </li></ul></ul><ul><li>Internet Control Message Protocol (ICMP) </li></ul><ul><ul><li>provides control and messaging capabilities </li></ul></ul><ul><li>Address Resolution Protocol (ARP) </li></ul><ul><ul><li>Determines the data link layer address, MAC address, for known IP addresses </li></ul></ul><ul><li>Reverse Address Resolution Protocol (RARP) </li></ul><ul><ul><li>Determines IP addresses when the MAC address is known </li></ul></ul>
  7. 7. Introduction <ul><li>The network access layer is also called the host-to-network layer. </li></ul><ul><li>It is the layer that make a physical link to the network media. </li></ul><ul><li>Modem protocol standards such as Serial Line Internet Protocol (SLIP) and Point-to-Point Protocol (PPP) provide network access through a modem connection </li></ul><ul><li>Network access layer functions include mapping IP addresses to physical hardware addresses and encapsulation of IP packets into frames. </li></ul>
  8. 8. Introduction <ul><li>The Internet uses the principle of network layer interconnection. </li></ul><ul><li>Internetworking must be scalable with regard to the number of networks and computers attached. </li></ul>
  9. 9. Internet Address <ul><li>Each computer in a TCP/IP network must be given a unique identifier, or IP address. </li></ul><ul><li>An IP address is a 32-bit sequence of 1s and 0s. </li></ul><ul><li>IP address is usually written as four decimal numbers separated by periods. </li></ul><ul><li>Using the IP address of destination network, a router can deliver a packet to the correct network. </li></ul><ul><li>When the packet arrives at a router connected to the destination network, the router uses the IP address to locate the particular computer </li></ul><ul><li>Every IP address has two parts, the first part identifies the system's network address . The second part, called the host part </li></ul>
  10. 10. Internet Address <ul><li>IP addresses are divided into classes to define the large, medium, and small networks. </li></ul>
  11. 11. Internet Address
  12. 12. Internet Address <ul><li>The network is reserved for loopback testing </li></ul><ul><li>The Class D address class was created to enable multicasting in an IP address. </li></ul><ul><li>The first four bits of a Class D address must be 1110 . </li></ul><ul><li>Reserved IP addresses </li></ul><ul><ul><li>Network address </li></ul></ul><ul><ul><ul><li>Used to identify the network itself </li></ul></ul></ul><ul><ul><li>Broadcast address </li></ul></ul><ul><ul><ul><li>Used for broadcasting packets to all the devices on a network </li></ul></ul></ul><ul><ul><ul><li>Data that is sent to the broadcast address will be read by all hosts on that network </li></ul></ul></ul>
  13. 13. Internet Address
  14. 14. Internet Address <ul><li>IANA manages the supply of IP addresses to ensure that duplication of publicly used addresses does not occur. </li></ul><ul><li>No two machines that connect to a public network can have the same IP address because public IP addresses are global and standardized. </li></ul><ul><li>Private networks that are not connected to the Internet may use any host addresses </li></ul><ul><li>Connecting a network using private addresses to the Internet requires translation of the private addresses to public addresses. </li></ul><ul><li>This translation process is referred to as Network Address Translation (NAT) which done by router </li></ul>
  15. 15. Internet Address Private IP Address
  16. 16. Obtaining IP Address <ul><li>Static Assignment </li></ul><ul><ul><li>Assigns and tracks IP addresses for each computer, printer, or server on the intranet. </li></ul></ul><ul><ul><li>Works best on small, infrequently changing networks </li></ul></ul><ul><li>RARP IP Assignment </li></ul><ul><ul><li>Associates a known MAC addresses with an IP addresses. </li></ul></ul><ul><ul><li>A RARP server must be present on the network to answer RARP requests </li></ul></ul><ul><ul><li>RARP requests are broadcast onto the LAN </li></ul></ul>
  17. 17. Obtaining IP Address <ul><li>BOOTP IP assignment </li></ul><ul><ul><li>The bootstrap protocol (BOOTP) operates in a client-server environment </li></ul></ul><ul><ul><li>The administrator creates a configuration file that specifies the parameters for each device. </li></ul></ul><ul><ul><li>The administrator must add hosts and maintain the BOOTP database </li></ul></ul><ul><ul><li>Every host on the network must have a BOOTP profile with an IP address assignment in it </li></ul></ul>
  18. 18. Obtaining IP Address <ul><ul><li>A device uses BOOTP to obtain an IP address when starting up. The device will send a broadcast IP packet </li></ul></ul><ul><ul><li>A BOOTP server receives the broadcast and then sends back a broadcast reply </li></ul></ul><ul><ul><li>If the client finds its own MAC address in the destination address field and a broadcast in the IP destination field, it takes and stores the IP address and other information supplied in the BOOTP reply message. </li></ul></ul>
  19. 19. Obtaining IP Address <ul><li>DHCP IP Management </li></ul><ul><ul><li>Dynamic host configuration protocol (DHCP) allows a host to obtain an IP address dynamically without having to set up an individual profile for each device. </li></ul></ul><ul><ul><li>A range of IP addresses must be define on a DHCP server. </li></ul></ul><ul><ul><li>The hosts contact the DHCP server and request an address. The DHCP server chooses an address and leases it to that host. </li></ul></ul><ul><ul><li>It allows users to be mobile </li></ul></ul><ul><ul><li>Offers a one to many ratio of IP addresses </li></ul></ul>
  20. 20. Obtaining IP Address <ul><li>Address Resolution Protocol (ARP) </li></ul><ul><ul><li>Automatically obtain MAC addresses for local transmission. </li></ul></ul><ul><ul><li>When a source determines the IP address for a destination, it then consults the ARP table in order to locate the MAC address for the destination. </li></ul></ul><ul><ul><li>If the source locates an entry in its table, it will associate the IP address to the MAC address </li></ul></ul><ul><ul><li>If not found, the host broadcasts an ARP request </li></ul></ul><ul><ul><li>If one of the local devices matches the IP address of the request, it sends back an ARP reply that contains its IP-MAC pair. </li></ul></ul>
  21. 21. Obtaining IP Address
  22. 22. Introduction to Subnetting <ul><li>Subnetting a network means to use the subnet mask to divide the network and break a large network up into smaller, more efficient and manageable segments , or subnets. </li></ul><ul><li>Subnet addresses include the network portion, plus a subnet field and a host field </li></ul>
  23. 23. Introduction to Subnetting <ul><li>Subnet mask is created by using binary ones in the host </li></ul><ul><li>If three bits were borrowed, the mask for a Class C address would be or /27. </li></ul><ul><li>The last two bits in the last octet, regardless of the IP address class, may never be assigned to the subnetwork </li></ul><ul><li>(2 power of borrowed bits ) – 2 = usable subnets </li></ul><ul><li>(2 power of remaining host bits ) – 2 = usable hosts </li></ul><ul><li>(2 power of borrowed bits ) = total subnets </li></ul><ul><li>(2 power of remaining host bits ) = total hosts </li></ul><ul><li>The available bits for assignment to the subnet field in Class A address is 22 bits while a Class B address has 14 bits. </li></ul>
  24. 24. Introduction to Subnetting
  25. 25. TCP/IP Transport Layer <ul><li>The transport layer provides transport services from the source host to the destination host. </li></ul><ul><li>It establishes a logical connection between the endpoints of the network. </li></ul><ul><li>Primary duties </li></ul><ul><ul><li>Segmentation of upper-layer application data </li></ul></ul><ul><ul><li>Establishment of end-to-end operations </li></ul></ul><ul><ul><li>Transport of segments from one end host to another end host </li></ul></ul><ul><ul><li>Flow control provided by sliding windows </li></ul></ul><ul><ul><li>Reliability with sequence numbers and acknowledgments </li></ul></ul>
  26. 26. TCP/IP Transport Layer <ul><li>Transmission Control Protocol (TCP) is a connection-oriented Layer 4 protocol that provides reliable full-duplex data transmission . </li></ul><ul><li>TCP is responsible for breaking messages into segments, reassembling them at the destination station, resending anything that is not received, and reassembling messages from the segments. </li></ul><ul><li>Protocols that use TCP include: FTP (File Transfer Protocol), HTTP (Hypertext Transfer Protocol), SMTP (Simple Mail Transfer Protocol), Telnet </li></ul>
  27. 27. TCP/IP Transport Layer <ul><li>User Datagram Protocol (UDP) is the connectionless transport protocol </li></ul><ul><li>It exchanges datagrams, without acknowledgments or guaranteed delivery. </li></ul><ul><li>UDP is designed for applications that do not need to put sequences of segments together </li></ul><ul><li>The protocols that use UDP include: TFTP (Trivial File Transfer Protocol), SNMP (Simple Network Management Protocol), DHCP (Dynamic Host Control Protocol), DNS (Domain Name System) </li></ul>
  28. 28. TCP/IP Transport Layer <ul><li>Both TCP and UDP use port (socket) numbers to pass information to the upper layers. </li></ul><ul><li>Port numbers are used to keep track of different conversations crossing the network at the same time. </li></ul><ul><li>Range of Port number </li></ul><ul><ul><li>Numbers below 1024 - Well-known ports numbers. </li></ul></ul><ul><ul><li>Numbers above 1024 - Dynamically assigned ports numbers. </li></ul></ul><ul><ul><li>Registered port numbers are those registered for vendor-specific applications. Most of these are above 1024. </li></ul></ul>
  29. 29. TCP/IP Transport Layer
  30. 30. Application Layer <ul><li>DNS (Domain Name System) </li></ul><ul><ul><li>To associate the contents of the site with the address of that site. </li></ul></ul><ul><ul><li>It is a system used on the Internet for translating names of domains and their publicly advertised network nodes into IP addresses . </li></ul></ul><ul><ul><li>A domain is a group of computers that are associated by their geographical location or their business type. </li></ul></ul><ul><ul><li>A domain name is a string of characters, number, or both. </li></ul></ul>
  31. 31. Application Layer <ul><li>FTP (File Transfer Protocol) </li></ul><ul><ul><li>To transfer files from one computer to another by copying and moving files from servers to clients, and from clients to servers. </li></ul></ul><ul><ul><li>Data transfer can occur in ASCII mode or in binary mode. </li></ul></ul><ul><li>TFTP (Trivial File Transfer Protocol) </li></ul><ul><ul><li>Uses User Datagram Protocol (UDP) </li></ul></ul><ul><ul><li>Used on the router to transfer configuration files and Cisco IOS images and to transfer files between systems that support TFTP. </li></ul></ul>
  32. 32. Application Layer <ul><li>HTTP (Hypertext Transfer Protocol) </li></ul><ul><ul><li>Works with the World Wide Web </li></ul></ul><ul><ul><li>http:// tells the browser which protocol to use. </li></ul></ul><ul><ul><li>www is the hostname of a server with a specific IP address. </li></ul></ul><ul><li>SNMP (Simple Network Management Protocol) </li></ul><ul><ul><li>enables network administrators to manage network performance, find and solve network problems, and plan for network growth. </li></ul></ul><ul><ul><li>Uses UDP as its transport layer protocol </li></ul></ul>
  33. 33. Application Layer <ul><ul><li>Three key components </li></ul></ul><ul><ul><ul><li>Network management system (NMS) </li></ul></ul></ul><ul><ul><ul><ul><li>Monitor and control managed devices. </li></ul></ul></ul></ul><ul><ul><ul><li>Managed devices </li></ul></ul></ul><ul><ul><ul><ul><li>Network nodes that contain an SNMP agent </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Collect and store management information and make this information available to NMSs </li></ul></ul></ul></ul><ul><ul><ul><li>Agents </li></ul></ul></ul><ul><ul><ul><ul><li>Network-management software modules that reside in managed devices. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Has local knowledge of management information </li></ul></ul></ul></ul>
  34. 34. Application Layer
  35. 35. Application Layer <ul><li>SMTP (Simple Mail Transfer Protocol) </li></ul><ul><ul><li>Transports email messages in ASCII format using TCP. </li></ul></ul><ul><ul><li>The most popular mail client protocols are POP3 and IMAP4, which both use TCP to transport data. </li></ul></ul><ul><ul><li>SMTP port (25) or to the POP3 port (110) </li></ul></ul><ul><li>Telnet </li></ul><ul><ul><li>Provides the ability to login to a remote Internet host that is running a Telnet server application and then to execute commands from the command line. </li></ul></ul><ul><ul><li>Telnet works at the application layer of the TCP/IP model. </li></ul></ul>