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  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 ModelTCP/IP FIGURE 3-1 TCP/IP compared to the OSI Model

TCP/IP Compared to the OSI 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 i nternetwork –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 FIGURE 3-2 Components of an IP datagram TCP

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 TransportUDP,, TCP Application Internet IP, ICMP Network Interface ARP

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 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? - 2 8, 2 16, 2 24  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  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 , 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, , 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