Chapter04  -- network protocols
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Chapter04 -- network protocols

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Basic Networking Guide

Basic Networking Guide

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Chapter04  -- network protocols Chapter04 -- network protocols Presentation Transcript

  • Chapter 4: Network Protocols Network+ Guide to Networks
  • Objectives
    • Identify the characteristics of TCP/IP, IPX/SPX, NetBIOS, and AppleTalk
    • Understand how key network protocols correlate to layers of the OSI Model
    • Identify the core protocols of the TCP/IP suite and describe their functions
  • Objectives (continued)
    • Understand the most popular protocol addressing schemes
    • Describe the purpose and implementation of the domain name system
    • Install protocols on Windows XP clients
  • Introduction To Protocols
    • Protocol is a rule that governs how networks communicate
      • Define the standards for communication between network devices
      • Vary according to their speed, transmission efficiency, utilization of resources, ease of setup, compatibility, and ability to travel between different LANs
  • Introduction To Protocols
      • Networks running more than one protocol are called multiprotocol networks
  • Transmission Control Protocol /Internet Protocol (TCP/IP)
      • 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
      • Extremely popular because of low cost
  • TCP/IP (continued)
      • Has ability to communicate between a multitude of dissimilar platforms
      • The core protocols are free and their code is available for anyone to read or modify
      • Its routable, because they carry Network layer addressing information that can be interpreted by a router
      • Has flexibility because it can run on virtually any combination of network operating systems or network media
    • TCP/IP Compared to the OSI Model
      • The TCP/IP suite of protocols can be divided into four layers that roughly correspond to the seven layers of the OSI Model
    TCP/IP (continued)
    • TCP/IP Compared to the OSI Model (continued)
      • Application layer
        • Applications gain access to the network through this layer, via protocols
      • Transport layer
        • Holds the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP), which provide flow control, error checking, and sequencing
    TCP/IP (continued)
    • TCP/IP Compared to the OSI Model (continued)
      • Internet layer
        • 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
      • Network Interface Layer
        • This layer handles the formatting of data and transmission to the network wire
    TCP/IP (continued)
    • The TCP/IP Core Protocols
      • Certain sub protocols of the TCP/IP suite
      • Operate in the Transport or Network layers of the OSI Model
    TCP/IP (continued)
    • Transmission Control Protocol (TCP)
      • Operates in the Transport layer of both the OSI and the TCP/IP Models and provides reliable data delivery services
      • TCP is a connection-oriented sub protocol
    TCP/IP (continued)
    • Fields belonging to a TCP segment are described in the following list:
      • Source port
      • Destination port
      • Sequence number
    TCP/IP (continued)
      • Acknowledgment number (ACK)
      • TCP header length
      • Reserved
      • Flags
      • Sliding-window size (or window)
    TCP/IP (continued)
      • Checksum - Allows the receiving node to determine whether the TCP segment became corrupted during transmission
      • Urgent pointer - Indicate a location in the data field
      • Options - Used to specify special options
    TCP/IP (continued)
      • Padding - Contains filler information to ensure that the size of the TCP header is a multiple of 32 bits
      • 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
    TCP/IP (continued)
    • User Datagram Protocol (UDP)
      • A connectionless transport service
      • UDP offers no assurance that packets will be received in the correct sequence
    TCP/IP (continued)
    • User Datagram Protocol (UDP)
      • Provides no error checking or sequencing
      • More efficient for carrying messages that fit within one data packet
    TCP/IP (continued)
    • Internet Protocol (IP)
      • Provides information about how and where data should be delivered, including the data’s source and destination addresses
      • IP is the sub protocol that enables TCP/IP to internetwork
    TCP/IP (continued)
    • Internet Protocol (IP)
      • IP datagram acts as an envelope for data and contains information necessary for routers to transfer data between different LAN segments
      • IP is an unreliable, connectionless protocol, which means that it does not guarantee delivery of data
    TCP/IP (continued)
    • Internet Control Message Protocol (ICMP)
      • An Internet layer protocol that reports on the success or failure of data delivery
      • ICMP announcements provide critical information for troubleshooting network problems
    TCP/IP (continued)
    • Address Resolution Protocol (ARP)
      • 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
    TCP/IP (continued)
    • Address Resolution Protocol (ARP) table
      • Dynamic ARP table entries are created when a client makes an ARP request that cannot be satisfied by data already in the ARP table
      • Static ARP table entries are those that someone has entered manually using the ARP utility
      • ARP can be a valuable troubleshooting tool
    TCP/IP (continued)
    • Reverse Address Resolution Protocol (RARP)
      • Allow the client to send a broadcast message with its MAC address and receive an IP address in reply
      • RARP was originally developed as a means for diskless workstations
    TCP/IP (continued)
    • Addressing in TCP/IP
      • Two kinds of addresses: Logical or physical
    TCP/IP (continued)
      • Logical (or Network layer) can be manually or automatically assigned and must follow rules set by the protocol standards
      • Physical (or MAC, or hardware) addresses are assigned to a device’s network interface card at the factory by its manufacturer
      • Addresses on TCP/IP-based networks are often called IP addresses
    TCP/IP (continued)
      • IP addresses are assigned and used according to very specific parameters
        • Each IP address is a unique 32-bit number, divided into four octets, or sets of 8-bits, that are separated by periods
        • An IP address contains two types of information: network and host
        • From the first octet you can determine the network class
        • Three types of network classes are used on modern LANs: Class A, Class B, and Class C
    TCP/IP (continued)
      • IP Addresses specific parameters continued
        • Class D and Class E addresses do exist, but are rarely used
        • Class D addresses are reserved for a special type of transmission called multicasting
          • Multicasting allows one device to send data to a specific group of devices
    TCP/IP (continued)
      • IP Addresses specific parameters continued
        • Some IP addresses are reserved for special functions, like broadcasts, and cannot be assigned to machines or devices
        • 127 is not a valid first octet for any IP address
        • The range of addresses beginning with 127 is reserved for a device communicating with itself, or performing loopback communication
    TCP/IP (continued)
    • The command used to view IP information on a Windows XP workstation is ipconfig
    TCP/IP (continued)
    • Binary and Dotted Decimal Notation
      • A decimal number between 0 and 255 represents each binary octet (for a total of 256 possibilities)
      • The binary system is the way that computers interpret IP addresses
      • In this system every piece of information is represented by 1s and 0s and each 1 or 0 constitutes a bit
    TCP/IP (continued)
    • Subnet Mask
      • 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
      • A more common term for subnet mask is net mask, and sometimes simply mask
      • Subnetting is a process of subdividing a single class of network into multiple, smaller logical networks, or segments
    TCP/IP (continued)
    • Assigning IP Addresses
      • Every node on a network must have a unique IP address
      • 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
    TCP/IP (continued)
      • A manually assigned IP address is called a static IP address
      • Most network administrators rely on a network service to automatically assign them
    TCP/IP (continued)
    • Two methods of automatic IP addressing: BOOTP and DHCP
      • 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
    TCP/IP (continued)
        • An IP address that is assigned to a device upon request and is changeable is known as a dynamic IP address
        • 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
    TCP/IP (continued)
      • Dynamic Host Configuration Protocol (DHCP)
        • An automated means of assigning a unique IP address to every device on a network
        • DHCP does not require a table of IP and MAC addresses on the server
        • DHCP does require configuration of DHCP service on a DHCP server
    TCP/IP (continued)
    • Terminating a DHCP Lease
      • A DHCP lease may expire based on the period established for it in the server configuration or it may be manually terminated
    • Sockets and Ports
      • 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
      • The use of port numbers simplifies TCP/IP communications and ensures that data are transmitted to the correct application
    TCP/IP (continued)
      • 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
      • 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
    TCP/IP (continued)
      • 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
      • Dynamic and/or Private Ports are those from 49152 through 65535 and are open for use without restriction
    TCP/IP (continued)
    • Addressing in IPv6
      • Known as IP next generation, or Ipng is slated to replace the current IP protocol, IPv4
      • IPv6 offers several advantages over IPv4, including a more efficient header, better security, better prioritization allowances, and automatic IP address configuration
      • The most valuable advantage IPv6 offers is its promise of billions and billions of additional IP addresses through its new addressing scheme
    TCP/IP (continued)
    • Addressing in IPv6 (continued)
      • The most notable difference between IP addresses in IPv4 and IPv6 is their size
        • IPv4 addresses are composed of 32 bits, IPv6 are eight 16-bit fields and total 128 bits
        • IPv4 address contains binary numbers separated by a period, each field in an IPv6 address contains hexadecimal numbers separated by a colon
    TCP/IP (continued)
    • 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
    TCP/IP (continued)
    • 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
      • A domain name is associated with a company or other type of organization
      • Local host name plus its domain name is a fully qualified host name
    TCP/IP (continued)
      • A domain name is represented by a series of character strings, called labels, separated by dots
        • Each label represents a level in the domain naming hierarchy
          • In the domain name, www.novell.com, “com” is the top-level domain (TLD), “novell” is the second-level domain, and “www” is the third-level domain
        • Domain names must be registered with an Internet naming authority that works on behalf of ICANN
    TCP/IP (continued)
    • Domain Name System (DNS)
      • A hierarchical way of associating domain names with IP addresses
      • “ DNS” refers to both the Application-layer service and the organized system of computers and databases
    TCP/IP (continued)
      • The DNS service does not rely on one file or even one server, but rather on many computers across the globe
        • These computers are related in a hierarchical manner, with thirteen computers, known as root servers, acting as the ultimate authorities
    TCP/IP (continued)
      • DNS service is divided into three components: resolvers, name servers, and name space
      • Resolvers are any hosts on the Internet that need to look up domain name information
    TCP/IP (continued)
      • Name servers (or DNS servers) are servers that contain databases of associated names and IP addresses and provide this information to resolvers on request
      • The term name space refers to the database of Internet IP addresses and their associated names
    TCP/IP (continued)
      • Resource record is a single record that describes one piece of information in the DNS database
        • An address resource record is a type of resource record that maps the IP address of an Internet-connected device to its domain name
        • Approximately 20 types of resource records are currently used
    TCP/IP (continued)
    • Some TCP/IP Application Layer Protocols
      • Telnet
        • A terminal emulation protocol used to log on to remote hosts using the TCP/IP protocol suite
        • Using Telnet, a TCP connection is established and keystrokes on the user’s machine act like keystrokes on the remotely connected machine
        • Telnet is notoriously insecure
    TCP/IP (continued)
    • Some TCP/IP Application Layer Protocols (continued)
      • File Transfer Protocol (FTP)
        • Used to send and receive files via TCP/IP
        • FTP commands will work from your operating system’s command prompt
        • Many FTP hosts accept anonymous logins
    TCP/IP (continued)
      • Trivial File Transfer Protocol (TFTP)
        • Enables file transfers between computers, but it is simpler (or more trivial) than FTP
        • TFTP relies on UDP at the Transport layer
        • TFTP is useful when you need to load data or programs on a diskless workstation
        • TFTP does not require a user to log on to a host
    TCP/IP (continued)
      • Network Time Protocol (NTP)
        • Used to synchronize the clocks of computers on a network
        • NTP depends on UDP for Transport layer services
        • NTP is a protocol that benefits from UDP’s quick, connectionless nature at the Transport layer
        • NTP is time-sensitive and cannot wait for the error checking that TCP would require
    TCP/IP (continued)
      • Packet Internet Groper (PING)
        • A utility that can verify that TCP/IP is installed, bound to the NIC, configured correctly, and communicating with the network
        • PING uses ICMP services to send echo request and echo reply messages that determine the validity of an IP address
        • By pinging the loopback address, 127.0.0.1, you can determine whether your workstation’s TCP/IP services are running
    TCP/IP (continued)
      • Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX) is a protocol originally developed by Xerox
      • Modified and adopted by Novell in the1980s for its NetWare network operating system
      • Microsoft’s implementation of IPX/SPX is called NWLink
    IPX/SPX
    • The IPX and SPX Protocols
      • 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
        • 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
    IPX/SPX (continued)
      • Sequenced Packet Exchange (SPX) belongs to the Transport layer of the OSI Model
        • A connection-oriented protocol and therefore must verify that a session has been established with the destination node before it will transmit data
    IPX/SPX (continued)
    • Addressing in IPX/SPX
      • IPX/SPX-based networks require that each node on a network be assigned a unique address to avoid communication conflicts
      • IPX is the component of the protocol that handles addressing, addresses on an IPX/SPX network are called IPX addresses
      • IPX addresses contain two parts: the network address and the node address
    IPX/SPX (continued)
  • NetBIOS and NetBEUI
      • 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
      • NetBEUI can support only 254 connections, however, and does not allow for good security
        • Because NetBEUI frames include only Data Link layer (or MAC) addresses and not Network layer addresses, it is not routable
    • Windows Internet Naming Service (WINS) - Provides a means of resolving NetBIOS names to IP addresses
      • A computer’s NetBIOS name and its TCP/IP host name are different entities, though you can have the same name for both
    NetBIOS and NetBEUI (continued)
      • WINS has the same relationship to NetBIOS as DNS has to TCP/IP
      • WINS does not assign names or IP addresses, but merely keeps track of which NetBIOS names are linked to which IP addresses
    NetBIOS and NetBEUI (continued)
      • The protocol suite originally designed to interconnect Macintosh computers
      • An AppleTalk network is separated into logical groups of computers called AppleTalk zones
    Appletalk
      • An AppleTalk node ID is a unique 8-bit or 16-bit number that identifies a computer on an AppleTalk network
      • An AppleTalk network number is a unique 16-bit number that identifies the network to which a node is connected
    Appletalk (continued)
      • Binding is the process of assigning one network component to work with another
      • You can manually bind protocols that are not already associated with a network interface
    Binding Protocols on a Windows XP Workstation
  • Summary
    • Characteristics of TCP/IP, IPX/SPX, NetBIOS, and AppleTalk
    • Network protocols correlate to layers of the OSI Model
    • Core protocols of the TCP/IP suite and their functions
  • Summary (continued)
    • The most popular protocol addressing schemes
    • Purpose and implementation of the domain name system
    • Install protocols on Windows XP clients