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Section 5.1• Explain why standards are necessary for networking• Explain how an Ethernet network functions• List Ethernet classifications
Section 5.2• Explain how a token-passing network functions• List wireless network classifications• Explain how wireless transmissions are sent
Section 5.3• Map TCP/IP protocols to the OSI model• Define TCP and IP• Explain IP addressing
Section 5.4• Describe the AppleTalk protocols• Explain the protocols NetBIOS and NetBEUI• Demonstrate knowledge of the NetWare protocols
pp. 136-1415.1
Main Ideas
Manufacturers need standards so their devices can communicate with each other. The IEEE 802.x standards define what happens at the Physical and Data Link Layers. 802.3 standards are for Ethernet networks. Ethernet networks use a contentious means of accessing the network called CSMA/CD.
Key Terms
Logical Link Control (LLC)
Ethernet
contention
frame
device driver
Guide to Reading
Common LAN Models
pp. 136-1415.1
IEEE 802.x
In the 1970s, the Institute of Electrical and Electronics Engineers (IEEE) established Project 802. It defined network standards for the physical components of a network.
Common LAN Models
pp. 136-1415.1
Project 802 standards fit into the OSI reference model with two differences:
• 802 is limited to the Physical and Data Link Layers of the OSI model.
• 802 divides the Data Link Layer into two sublayers
– Logical Link Control Logical Link Control (LLC)(LLC)– Media Access Control (MAC)
Logical Link Control (LLC)Logical Link Control (LLC) A sublayer of the Data Link Layer that is responsible for establishing and terminating links to other computers and sequencing and acknowledging frames and controlling frame traffic. (p. 136)
IEEE 802.x
Common LAN Models
pp. 136-1415.1
IEEE 802.x
The IEEE 802 committee defines the specifications for LAN architectures, including:
• Ethernet
• Token bus
• Wireless personal area networks
Common LAN Models
pp. 136-1415.1
EthernetEthernet could be considered the parent of LAN technology.
An earlier network, named ALOHA, was the first to use CSMA/CD as its means of controlling network access and contentioncontention.
EthernetEthernet A LAN architecture that uses a bus topology and relies on CSMA/CD to regulate traffic on the main communication line. It uses a bus topology and is based on the IEEE 802.3 standard. (p. 137)
contentioncontention The competition among stations on a network for the opportunity to use a communication line or network resource. (p. 137)
IEEE 802.3: Ethernet Standard
Common LAN Models
pp. 136-1415.1
IEEE 802.3
Many LANs rely on CSMA/CD to:
• Gain access to the network when they have packets to transmit.• Ensure that two nodes do not try to transmit at the sametime.
A collision occurs if two computers put data on the cable at the same time.
Common LAN Models
pp. 136-1415.1
IEEE 802.3
One drawback of Ethernet networks is the limited number of nodes a network can support. The 5-4-3 rule was created to help maintain network efficiency. It specifies that there can be no more than 5 cable segments, 4 repeaters, and 3 populated segments that can exist in any collision domain.
Common LAN Models
pp. 136-1415.1
IEEE 802.3
Ethernet networks vary in topology, speed, and cabling but have the following elements in common:
• Use CSMA/CD as the means of gaining access to the network.
• Are all defined in the IEEE 802.3 specifications.
• Rely on broadcast transmissions that deliver signals to all nodes at the same time.
• Are primarily baseband networks.
Common LAN Models
pp. 136-1415.1
Ethernet networks use a frame to transmit information.
The frame ranges from 64 bytes to 1,518 bytes but are made of the same pieces.
frame A format that Ethernet networks use for transmitting data packets. The frame contains the preamble, source and destination addresses, data, type of protocol used to send the frame, and the CRC. (p. 139)
IEEE 802.3
Common LAN Models
pp. 136-1415.1
Network devices use device drivers to allow hardware components to communicate to each other.
NIC drivers provide a virtual communication channel between the computer and the NIC.
device driverdevice driver Software that helps a computer work with a particular device. (p. 140)
Drivers and the NIC
Common LAN Models
pp. 136-1415.1
You Try It
• Activity 5A – Locating NIC Drivers (p. 140)
Common LAN Models
pp. 142-1475.2
Main Ideas
Token-passing networks take turns to gain access to the network. Token-passing networks can reliably determine when each computer will be able to transmit. Wireless networks rely on a type of contentious access known as CSMA/CA.
Key Terms
Attached Resource Computer Network (ARCnet)Token RingMultistation Access Unit (MAU)Integrated Services LAN (ISLAN)Integrated Services Digital Network (ISDN)carrier sense multiple access with collision avoidance (CSMA/CA)Wi Fi
Guide to Reading
Other LAN Models
pp. 142-1475.2
Tokens and Token Passing
Token-passing networks work like a relay race, passing the token in a predetermined order through the network.
Only the node that currently holds the token is allowed to transmit and it can only transmit a single packet.
Other LAN Models
pp. 142-1475.2
ARCNetARCNet was established before the IEEE developed the specifications for networks. It is popular for smaller networks because it is flexible and easy to set up.
Attached Resource Attached Resource Computer Network Computer Network (ARCnet)(ARCnet) A PC-based LAN architecture that corresponds to the IEEE 802.4 specification. An ARCnet is built using either a bus or a star topology. (p. 143)
IEEE 802.4 and ARCNet
Other LAN Models
pp. 142-1475.2
Token RingToken Ring is an IBM architecture separate from the IEEE token ring.
Token Ring relies on nodes that are connected to one of more hubs called multistation multistation access units (MAU)access units (MAU)..
Token RingToken Ring An IBM-designed architecture created to connect PC’s with IBM’s larger midrange and mainframe computers. (p. 144)
Multistation Access Unit Multistation Access Unit (MAU)(MAU) The connection or hub that forms a logical ring. A Token Ring has a logical ring topology. (p. 144)
IEEE 802.5 and Token Ring
Other LAN Models
pp. 142-1475.2
IEEE 802.5 and Token Ring
A Token Ring network:
• Typically transfers information at 1 Mbps or 4 Mbps per second (IEEE version) or at 4 Mbps or 16 Mbps (IBM version)• Uses baseband transmission• Is based on twisted-pair or fiber optic cable
Other LAN Models
pp. 142-1475.2
Other wired IEEE 802 specifications include:
• Isochronous LAN• Integrated Services LAN Integrated Services LAN (ISLAN)(ISLAN)• Integrated Services Integrated Services Digital Network (ISDN)Digital Network (ISDN)
Integrated Services LAN Integrated Services LAN (ISLAN)(ISLAN) Isochronous LANs aimed at enabling multimedia capabilities on a network. (p. 145)
Integrated Services Digital Integrated Services Digital Network (ISDN)Network (ISDN) A technology that delivers different types of information—voice, data, video—in digital form over standard telephone cabling. (p. 145)
Other IEEE LAN Specifications
Other LAN Models
pp. 142-1475.2
Other IEEE LAN Specifications
IEEE 802.11 set standards for wireless LAN communications. These networks are used where:
• Nodes must move around freely.
• Network connections are needed in a busy area.
• Connections are unreliable or dependent on external factors.
• It is difficult or impossible to wire the building.
Other LAN Models
pp. 142-1475.2
Wireless networks use CSMA/CACSMA/CA to transmit data through the network.
The three major variations of wireless networking, 802.11a, 802.11b, and 802.11g are commonly referred to as Wi FiWi Fi.
carrier sense multiple carrier sense multiple access with collision access with collision avoidance (CSMA/CA)avoidance (CSMA/CA) These nodes “listen” to the transmission medium for a chance to transmit. (p. 145)
Wi FiWi Fi In wireless network technology, the three standards 802.11a, 802.11b, and 802.11g are commonly referred to as this. (p. 145)
Other IEEE LAN Specifications
Other LAN Models
pp. 142-1475.2
Other IEEE LAN Specifications
At the Physical Layer, wireless LANs rely on two different methods of transmission:
• Diffused infrared light signal
• Radio signals
Other LAN Models
pp. 149-1535.3
Main Ideas
TCP establishes a connection between hosts in order to reliably transmit data. IP relies on a system of addresses to locate individual hosts on the network. IP packets can be routed from one network to another.
Key Terms
Transmission Control Protocol (TCP)
Internet Protocol (IP)
Domain Name System (DNS)
User Datagram Protocol (UDP)
Guide to Reading
Other LAN Models
pp. 149-1535.3
As more and more companies found it essential to “internetwork” with other networks, Transmission Control Transmission Control Protocol/Internet Protocol/Internet Protocol (TCP/IP)Protocol (TCP/IP) emerged as a standard.
Transmission Control Transmission Control Protocol (TCP)Protocol (TCP) A protocol that creates a connection between the sending and receiving computers, and then makes sure that all the data arrive safely. (p. 149)
Internet Protocol (IP)Internet Protocol (IP) A protocol responsible for routing packets, sometimes through many different networks. (p. 149)
Introduction to TCP/IP
Other LAN Models
pp. 149-1535.3
Every time you use the Internet, you are working with numeric IP addresses. Your Web browser uses a Domain Domain Name System (DNS)Name System (DNS) to connect the domain name to the 32-bit number of the IP address.
Domain Name Server Domain Name Server (DNS)(DNS) Web browsers use this to locate the IP address of the domain name that the user entered in the address bar of the browser (p. 150)
Introduction to TCP/IP
Other LAN Models
pp. 149-1535.3
Introduction to TCP/IP
Building on the TCP/IP stack are other protocols, including:
• File Transfer Protocol (FTP)
• Telnet
• Simple Mail Transfer Protocol (SMTP)
• Simple Network Management Protocol (SNMP)
• Hypertext Transfer Protocol (HTTP)
Other LAN Models
pp. 149-1535.3
TCP/IP and OSI
TCP/IP and the OSI do not exactly match up. But each of the TCP/IP layers correspond to one or more of the OSI layers.
Other LAN Models
pp. 149-1535.3
The Transport Layer of the TCP/IP can use either TCP or User Datagram User Datagram Protocol (UDP)Protocol (UDP) depending on the requirements of the transmission.
User Datagram Protocol User Datagram Protocol (UDP)(UDP) A connectionless transport protocol that is responsible for end-to-end transmission of data. It sends the data, but provides little in the way of error correction. (p. 151)
TCP/IP and OSI
Other LAN Models
pp. 149-1535.3
Physical Address
Every computer in the world is assigned a unique IP address. The address consists of two parts, a network address and an address that identifies the node or host.
Depending on your network configuration, your IP address may be fixed, or assigned to your computer when you boot up.
Other LAN Models
pp. 149-1535.3
You Try It
• Activity 5B – Finding Your IP Address and MAC Address
Using Windows (p. 152)• Activity 5C – Finding Your IP Address and MAC Address
Using UNIX (p. 153)
Other LAN Models
pp. 155-1585.4
Main Ideas
Many protocol stacks provide services and communication on different types of networks. AppleTalk is used for Macintosh networks. Microsoft Windows-based computers use the NetBIOS interface. NetWare is hardware-independent network software that allows networks running on different architectures to be joined together.
Key Terms
AppleTalkNetwork Basic Input/ Output System (NetBIOS)NetBIOS Extended User Interface (NetBEUI)NetWareInternetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX)
Guide to Reading
Other Models and Protocols
pp. 155-1585.4
Apple Computer’s LAN hardware and software use a protocol stack called AppleTalk.
AppleTalkAppleTalk corresponds to five of the seven layers of the OSI reference model.
AppleTalk Transaction AppleTalk Transaction Protocol (ATP)Protocol (ATP) A protocol in an AppleTalk network that transports packets. (p. 156)
AppleTalk
Other Models and Protocols
pp. 155-1585.4
Most applications that run within Windows use NetBIOSNetBIOS. It has four primary functions.
• Name Recognition
• Datagram Service
• Session service
• NIC/session status
Network Basic Network Basic Input/Output System Input/Output System (NetBIOS)(NetBIOS) An interface that evolved into a standard method for applications to access protocols in the Transport Layer. (p. 156)
NetBIOS
Other Models and Protocols
pp. 155-1585.4
Although NetBEUINetBEUI is small and fast, it does not support routing. This restricts its usefulness to only a single segment of a LAN.
NetBIOS Extended User NetBIOS Extended User Interface (NetBEUI)Interface (NetBEUI) A protocol developed by IBM in the mid-1980s and was designed for LANs of up to 200 computers. (p. 157)
NETBEUI
Other Models and Protocols
pp. 155-1585.4
NETBEUI
NetBEUI was designed for small networks. On Microsoft Windows OS, it acts as a go-between for the lower and higher levels.
Other Models and Protocols
pp. 155-1585.4
Novell Corporation introduced NetWareNetWare early in the development of networking.
Internetwork Packet Internetwork Packet Exchange/Sequenced Exchange/Sequenced Packet Exchange Packet Exchange (IPX/SPX)(IPX/SPX) is a routable protocol developed by Novell that can be used for larger networks.
NetWareNetWare A software networking product that runs on top of existing hardware, such as that used in the Ethernet and Token Ring networks. See also Novell Netware. (p. 158)
Internetwork Packet Internetwork Packet Exchange/Sequenced Exchange/Sequenced Packet Exchange Packet Exchange (IPX/SPX)(IPX/SPX) A protocol stack that was designed by Novell for its NetWare networks. (p. 158)
Netware Protocols and IPX/SPX
Other Models and Protocols
pp. 155-1585.4
Netware Protocols and IPX/SPX
Notice how some of the NetWare protocols operate at several OSI levels simultaneously.
Other Models and Protocols
Resources
For more resources on this chapter, go to the Introduction to Networks and Networking Web site at http://networking.glencoe.com.
Chapter 5
