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Addressing Through the Layers. Data Link Layer Address Network Layer Address. Data Link Layer Address. Also called MAC address , after Media Access Control (MAC) sublayer Number uniquely defining a network node Manufacturer-hard codes the address Block ID Device ID. Network Layer Address.
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Addressing Through the Layers • Data Link Layer Address • Network Layer Address
Data Link Layer Address • Also calledMAC address, after Media Access Control (MAC) sublayer • Number uniquely defining a network node • Manufacturer-hard codes the address • Block ID • Device ID
Network Layer Address • Resides at Network level of OSI Model • Follows hierarchical addressing scheme • Can be assigned through operating system software • Why would we use BOTH a Network address AND a MAC address?
Data Link Layer Sublayers • LLC • Upper sublayer • Provides common interface • Supplies reliability and flow control services • MAC • Lower sublayer • Appends the physical address of the destination computer onto the frame • IEEE Ethernet and Token Ring differ here
Chapter Three Network Protocols
Chapter Objectives • Identify the characteristics of TCP/IP, IPX/SPX, NetBIOS, and AppleTalk • Understand the position of network protocols in the OSI Model • Identify the core protocols of each protocol suite and its functions • Understand each protocol’s addressing scheme • Install protocols on Windows 95 and Windows NT clients
Introduction to Protocols • Protocols • Rules a network uses to transfer data • Protocols that can span more than one LAN segment are routable • Multiprotocol Network • Network using more than one protocol
TCP/IP • Transmission Control Protocol/Internet Protocol (TCP/IP) • Suite of small, specialized protocols called subprotocols OSI Model TCP/IP FIGURE 3-1 TCP/IP compared to the OSI Model
TCP/IP Compared to theOSI Model • Application layer roughly corresponds to Application and Presentation layers • Transport layer roughly corresponds to Session and Transport layers • Internet layer is equivalent to the Network layer • Network Interface layer roughly corresponds to Data Link and Physical layers
Internet Protocol (IP) • Provides information about how and where data should be delivered • Subprotocol enabling TCP/IP to internetwork • Traverse more than one LAN segment and more than one type of network through a router • Subnets • The individual networks joined together by routers in an internetwork
Internet Protocol (IP) • IP Datagram • IP portion of a TCP/IP frame that acts as an envelope for data • Contains information necessary for routers to transfer data between subnets TCP FIGURE 3-2 Components of an IP datagram
Internet Protocol (IP) • What is a Datagram? • Packaged data sent without establishment of a communication channel or connection • IP does not guarantee delivery of data • Connectionless • Allows the protocol to service a request without requesting a verified session and without guaranteeing delivery of data
Transport Control Protocol (TCP) • Provides reliable data delivery services • Connection oriented • Requires the establishment of a connection between communicating nodes before the protocol will transmit data • TCP segment • Holds the TCP data fields • Becomes encapsulated by the IP datagram
Transport Control Protocol (TCP) • Port • Address on host where an application makes itself available to incoming data FIGURE 3-3 A TCP segment header
TCP/IP Protocols Telnet, FTP, SMTP, SNMP Application UDP,, TCP Transport Internet IP , ICMP ARP Network Interface
Additional Core Protocols of the TCP/IP Suite • User Datagram Protocol (UDP) • A connectionless transport service • Less overhead than TCP • Internet Control Message Protocol (ICMP) • Notifies the sender that something has gone wrong in the transmission process and that packets were not delivered • No error control • PING uses this
Additional Core Protocols of the TCP/IP Suite • Address Resolution Protocol (ARP) • Obtains the MAC address of a host or node • Creates a local database mapping the MAC address to the host’s IP address • Used in conjunction with IP
TCP/IP Application Layer Protocols • Telnet is used to log on to remote hosts using TCP/IP Protocol • File Transfer Protocol (FTP) is used to send and receive files via TCP/IP • Simple Mail Transfer Protocol (SMTP)is responsible for moving messages from one e-mail server to another, using the Internet and other TCP/IP-based networks • Simple Network Management Protocol (SNMP) manages devices on a TCP/IP network
Addressing in TCP/IP • IP Address • Logical address used in TCP/IP networking • Unique 32-bit number • Divided into four groups of octets (8-bit bytes) • Separated by periods
Addressing in TCP/IP • How did we get the # of hosts? - 28 , 216 , 224 • Though 8 bits have 256 possible combinations, only the numbers 1 through 254 are used to identify networks and hosts • Numbers 0 and 255 are reserved for broadcasts • Transmissions to all stations on a network TABLE 3-1 Commonly used TCP/IP classes (4 exist)
Addressing in TCP/IP • Loopback address • IP address reserved for communicating from a node to itself • Value of the loopback address is always 127.0.0.1 • InterNIC • Authority for Internet IP addressing and domain name registration • Also known as Network Solutions
Addressing in TCP/IP • Firewall • Specialized device • Selectively filters or blocks traffic between networks • May be strictly hardware-based or may involve a combination of hardware and software • Host • Computer connected to a network using the TCP/IP protocol
Addressing in TCP/IP • In IP address 131.127.3.22, to convert the first octet (131) to a binary number: • On Windows 95, click Start, point to Programs, point to Accessories, then click Calculator • Click View, then click Scientific (make sure Dec option button is selected) • Type 131, then click Bin option button • The binary number 131, 10000011, appears in the display window
Addressing in TCP/IP • Static IP address • IP address manually assigned to a device • Dynamic Host Configuration Protocol protocol • Application layer protocol • Manages the distribution of IP addresses on a network
Viewing IP Information • On a Windows 95 workstation connected to a network • Click Start, then click Run • Type winipcfg • (ipconfig /all (NT at DOS prompt) • Click OK • Click More Info • Click OK to close window FIGURE 3-4 Example of an IP configuration window
Addresses and Names • In addition to using IP addresses, TCP/IP networks use names for networks and hosts • Each host requires a host name • Each network requires a network name, also called a domain name • Symbolic name that identifies and Internet domain
IPX/SPX • Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX) • Protocol originally developed by Xerox • Modified and adopted by Novell in the 1980s for the NetWare network operating system • NWLink - Microsoft IPX/SPX emulation FIGURE 3-6 IPX/SPX compared to the OSI Model
IPX/SPX Core Protocols • IPX • Network layer • Connectionless routing • Sequence Packet Exchange (SPX) • Works in tandem with IPX to ensure data are received (and acknowledged): • Whole • In sequence • Error free
IPX/SPX Core Protocols • Service Advertising Protocol (SAP) • Runs directly over IPX • Used by NetWare servers and routers to advertise to entire network which services they can provide • NetWare Core Protocol (NCP) • Handles requests for services between clients and servers • Read for yourself
NetBIOS and NetBEUI • Network Basic Input Output System (NetBIOS) • Originally designed by IBM to provide Transport and Session layer services • Adopted by Microsoft as its foundation protocol • Microsoft added Application layer component called NetBIOS Enhanced User Interface (NetBEUI)
NetBEUI • Fast and efficient protocol • Consumes few network resources • Provides excellent error correction • Requires little configuration • 254 connection limit removed for later versions • Non routable
AppleTalk • Protocol suite used to interconnect Macintosh computers • Originally designed to support peer-to-peer networking among Macintoshes • Can now be routed between network segments and integrated with NetWare- and Microsoft-based networks
Installing Protocols • After installing protocols, they must be binded • Binding • Process of assigning one network component to work with another