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Transcript
Chapter Three Network Protocols Objectives Identify characteristics of TCP/IP, IPX/SPX, NetBIOS, and AppleTalk Understand position of network protocols in OSI Model Identify core protocols of each protocol suite and its functions Understand each protocol’s addressing scheme Install protocols on Windows 98 and Windows 2000 clients Introduction to Protocols Protocol Rules 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 OSI Model TCP/IP Transmission Control Protocol/Internet Protocol (TCP/IP) Suite of small, specialized protocols called subprotocols Figure 3-1: TCP/IP compared to the OSI Model TCP/IP Compared to the OSI Model Application layer roughly corresponds to Session, Application, and Presentation layers of OSI Model Transport layer roughly corresponds to Transport layers of OSI Model Internet layer is equivalent to Network layer of OSI Model Network Interface layer roughly corresponds to Data Link and Physical layers of OSI Model The TCP/IP Core Protocols Certain subprotocols of TCP/IP suite Operate in Transport or Network layers of OSI Model Provide basic services to protocols in other layers of TCP/IP TCP and IP are most significant core protocols in TCP/IP suite Internet Protocol (IP) Provides information about how and where data should be delivered Subprotocol that enables TCP/IP to internetwork To internetwork is to traverse more than one LAN segment and more than one type of network through a router In an internetwork, the individual networks that are joined together are called subnetworks Internet Protocol (IP) IP datagram IP portion of 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 Internet Protocol (IP) IP is an unreliable, connectionless protocol, which means it does not guarantee delivery of data Connectionless Allows protocol to service a request without requesting verified session and without guaranteeing delivery of data Transport Control Protocol (TCP) TCP Provides reliable data delivery services Connection-oriented subprotocol Requires establishment of connection between communicating nodes before protocol will transmit data TCP segment Holds TCP data fields Becomes encapsulated by IP datagram Transport Control Protocol (TCP) Port Address on host where application makes itself available to incoming data Figure 3-3: A TCP segment Additional Core Protocols of the TCP/IP Suite User Datagram Protocol (UDP) Connectionless transport service Internet Control Message Protocol (ICMP) Notifies sender of an error in transmission process and that packets were not delivered Address Resolution Protocol (ARP) Obtains MAC address of host or node Creates local database mapping MAC address to host’s IP address TCP/IP Application Layer Protocols Telnet Used to log on to remote hosts using TCP/IP protocol suite File Transfer Protocol (FTP) Used to send and receive files via TCP/IP Simple Mail Transfer Protocol (SMTP) 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) that are separated by periods IP addresses are assigned and used according to very specific parameters Addressing in TCP/IP Table 3-1: Commonly used TCP/IP classes 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 Broadcast are transmissions to all stations on a network 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 Internet Corporation for Assigned Names and Numbers (ICANN) Non-profit organization currently designated by U.S. government to maintain and assign IP addresses Addressing in TCP/IP Firewall Specialized device (typically a router) 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 2000, 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 equivalent of 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 (DHCP) Application layer protocol Manages dynamic distribution of IP addresses on a network Viewing Current IP Information Figure 3-4: Example of an IP configuration window Viewing Current IP Information Figure 3-5: IP address information on a Windows 2000 workstation 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 Together, host name and domain name constitute the fully qualified domain name (FQDN) IPX/SPX Internetwork Packet Exchange/Sequence d Packet Exchange (IPX/SPX) Protocol originally developed by Xerox Modified and adopted by Novell in the 1980s for the NetWare network operating system Figure 3-6: IPX/SPX compared to the OSI Model IPX/SPX Core Protocols Internetwork Packet Exchange (IPX) Operates at Network layer of OSI Model Provides routing and internetworking services Similar to IP in TCP/IP suite Figure 3-7: Components of an IPX datagram IPX/SPX Core Protocols Sequenced Packet Exchange (SPX) Belongs to Transport layer of OSI Model Works in tandem with IPX to ensure data are received: Whole In sequence Error free IPX/SPX Core Protocols Figure 3-8: SPX packet encapsulated by an IPX datagram IPX/SPX Core Protocols Service Advertising Protocol (SAP) Works in Application, Presentation, Session, and Transport layers of OSI Model Runs directly over IPX Used by NetWare servers and routers to advertise to entire network which services they can provide IPX/SPX Core Protocols NetWare Core Protocol (NCP) Works within Presentation and Sessions layers of OSI Model Works over IPX Handles requests for services between clients and servers Addressing in SPX/IPX IPX address Address assigned to a device on an IPX/SPX network Contains two parts: Network address (external network number) Node address 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 NetBEUI NetBIOS and NetBEUI NetBIOS Enhanced User Interface Fast and efficient protocol Consumes few network resources Provides excellent error correction Requires little configuration Can handle only 254 connections Does not allow for good security NetBIOS and NetBEUI Compared to the OSI Model Figure 3-9: NetBIOS/NetBEUI compared to the OSI Model NetBIOS Addressing Figure 3-10: Identification tab in Network properties 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 Microsoftbased networks AppleTalk networks are separated into logical groups of computers called AppleTalk zones AppleTalk and OSI Model Figure 3-11: AppleTalk protocol compared to OSI Model AppleTalk Subprotocols AppleShare AppleTalk Filing Protocol (AFP) AppleTalk Session Protocol (ASP) AppleTalk Transaction Protocol (ATP) AppleTalk Subprotocols Name Binding Protocol (NBP) Routing Table Maintenance Protocol (RTMP) Zone Information Protocol (ZIP) Datagram Delivery Protocol (DDP) Addressing in AppleTalk AppleTalk node ID Unique 8-bit or 16-bit number identifying a computer on an AppleTalk network AppleTalk network number Unique 16-bit number identifying the network to which a node is connected Installing Protocols After installing protocols, they must be binded to NICs and services they run on or with Binding Process of assigning one network component to work with another Chapter Summary Protocols define standards for communication between nodes on a network Protocols vary in speed, transmission efficiency, utilization of resources, ease of setup, compatibility, and ability to travel between one LAN segments TCP/IP is becoming most popular network protocol Chapter Summary TCP/IP suite of protocols can be divided into four layers roughly corresponding to seven layers of OSI Model Operating in Transport or Network layers of OSI Model, TCP/IP core protocols provide communications between hosts on a network Each IP address is a unique 32-bit number, divided into four groups of octets separated by periods Chapter Summary Every host on a network must have a unique number Internetworking Packet Exchange/Sequenced Packet Exchange (IPX/SPX) is a protocol originally developed by Xerox then modified and adopted by Novell in the 1980s for its NetWare network operating system Core protocols of IPX/SPX provide services at Transport and Network layers of OSI Model Chapter Summary Addresses on an IPX/SPX network are called IPX addresses Network Basic Input Output System (NetBIOS) was originally developed by IBM to provide Transport and Session layer services Microsoft adopted NetBIOS as its foundation protocol, then added an Application layer component called NetBIOS Enhanced User Interface (NetBEUI) Chapter Summary To transmit data between network nodes, NetBIOS needs to know how to reach each workstation Each workstation must have a NetBIOS name AppleTalk is the the protocol suite used to interconnect Macintosh computers An AppleTalk network is separated into logical groups of computers called AppleTalk zones Chapter Summary Though Apple has improved AppleTalk’s ability to use different network models and span network segments, it remains unsuited to large LANs or WANs In addition to zone names, AppleTalk uses node IDs and network numbers to identify computers on a network Though some protocols (such as NetBIOS) require no configuration after installation, others (such as TCP/IP) do require configuration