Hands-On Microsoft Windows Server 2003 Networking Chapter Three TCP/IP Architecture

2 Objectives Describe the overall architecture of TCP/IP Describe application layer protocols Discuss transport layer protocols Understand the role of various network layer protocols including IP, ICMP, and ARP Understand network interface layer protocols Describe different physical layer protocols Discuss changes to IP introduced with IPv6

3 TCP/IP Model Application layer –Provides access to network resources –Defines rules, commands, and procedures Transport layer –Breaks large messages into smaller packets of information –Tracks whether packets arrived at final destination Internet layer –Responsible for logical addressing Networking interface layer –Consists of network card driver and circuitry on network card itself

4 TCP/IP Architecture

5 Hypertext Transfer Protocol (HTTP) The most common protocol used on the Internet today Defines the commands that Web browsers can send and how Web servers are capable of responding Common mechanisms for passing data from a Web server to an application –Common Gateway Interface (CGI) –Internet Server Application Programmer Interface (ISAPI) –Netscape Server Application Programmer Interface (NSAPI)

6 File Transfer Protocol (FTP) A simple file-sharing protocol Includes commands for uploading and downloading files Implemented in stand-alone FTP clients as well as in Web browsers

7 Telnet A terminal emulation protocol used to remotely connect to Unix and Linux Systems Does not support a graphical user interface (GUI), only text Telnet client only responsible for displaying information on the screen and passing input to the server Can have many telnet clients connected to a single server at one time

8 Simple Mail Transfer Protocol (SMTP) Used to send and receive messages between servers Used by client software, such as Outlook Express, to send messages to the server Is never used to retrieve that is being read

9 Post Office Protocol version 3 (POP3) The most common protocol used for reading e- mail messages Does not support sending messages Only supports a single inbox and does not support multiple folders for storage on the server

10 Internet Message Access Protocol version 4 (IMAP4) Another common protocol used to read messages Allows for multiple folders on the server side to store messages

11 Transport Layer Protocols Responsible for getting data ready to move across the network Port –Used by transport layer protocols to direct network information to the proper service Transport layer protocols in the TCP/IP protocol suite –Transmission Control Protocol (TCP) –User Datagram Protocol (UDP)

12 Common Services and Ports

13 Transmission Control Protocol (TCP) The most commonly used transport layer protocol Connection-oriented and reliable Establishment of a connection is a three-packet process between the source and destination host Syn bit –Indicates that the packet is a request to negotiate a connection

14 Transmission Control Protocol (TCP) (Continued) Ack bit –An option in a packet that indicates this packet is a response to the first packet Sliding Window –Process used to track which packets have been received by the destination host

15 TCP Three-way Handshake

16 User Datagram Protocol (UDP) Connectionless and unreliable Has no sliding window The appropriate transport layer protocol to use when you are unconcerned about missing packets Use also when the amount of data being exchanged is very small

17 Internet Layer Protocols Responsible for all tasks related to logical addressing Internet Protocol (IP) –Responsible for the logical addressing of each packet created by the transport layer Routing Information Protocol (RIP) and Open Shortest Path First (OSPF) –Responsible for defining how paths are chosen through the internetwork from one computer to another

18 Internet Layer Protocols (Continued) Internet Control Messaging Protocol (ICMP) –Used to send IP error and control messages between routers and hosts –Ping utility uses ICMP packets to test connectivity between hosts

19 Common ICMP Packet Types

20 Internet Layer Protocols (Continued) Internet Group Management Protocol (IGMP) –Used for the management of multicast groups Address Resolution Protocol (ARP) –Used to convert logical IP addresses to physical MAC addresses –Data packets have four addresses: Source IP address Destination IP address Source MAC address Destination MAC address –Uses a two-packet process to find the MAC address of the destination computer

21 Computer A communicates with Computer B

22 ARP Request Packet

23 ARP Reply Packet

24 Communication Across a Router

25 Network Interface Layer Protocols Institute of Electrical and Electronics Engineers (IEEE) –Has system of numbered committees that each defines a different network interface layer protocol Ethernet –The most common network interface layer protocol used in corporate networks today Token Ring –Was commonly implemented with mainframe computers –Uses twisted pair cabling and operates at 4 Mbps or 16 Mbps

26 Network Interface Layer Protocols (Continued) Wireless LAN –One of the fastest growing network types –802.11b standard defines the most common wireless standard Bluetooth –Short-range wireless communication system –Has maximum distance of approximately 30 feet and maximum speed of 720 Kbps

27 Institute of Electrical and Electronics Engineers (IEEE) Protocols

28 Ethernet Cabling Types and Speeds

29 IPv6 Changes Newer versions of TCP and UDP CHECKv4.EXE –Utility provided by Microsoft to help developers find code that must be modified to work with IPv6 Neighbor Solicitation multicast packet –Used to find the MAC address of an IPv6 host –Replaces ARP Multicast Listener Discovery (MLD) –Replaces the functionality of IGMP

30 Summary TCP/IP model –Application layer –Transport layer –Internet layer –Network interface layer

31 Summary (Continued) Application layer protocols –HTTP: the most common protocol in use –FTP: used for transferring files across the Internet –Telnet: used to remotely connect to UNIX and Linux systems –SMTP: used to send and receive messages –POP3: most common protocol used for reading e- mail messages –IMAP4: used for reading messages Transport layer protocols –TCP: connection-oriented and reliable –UDP: connectionless and unreliable

32 Summary (Continued) Internet layer protocols –Responsible tasks related to logical addressing –Includes IP, RIP, OSPF, ICMP, IGMP, and ARP Ethernet –The most common network interface layer protocol in use Wireless LANs –One of the fastest growing network types IPv6 changes –New versions of TCP and UDP –Discontinued use of ARP –Replacement of IGMP with Multicast Listener Discovery