Introducing Network Standards Open Systems Interconnection (OSI) Model IEEE 802.x Standard Device Drivers and OSI 1

Open Systems Interconnection (OSI) Model 2 Network Communications OSI Model Windows NT and the OSI Model

Network Communications 3 Sending Computer Must: Recognize data Divide it into manageable chunks Add information to determine its location and identify the receiver Add timing and error-checking information Put data on the network and send it

Seven-Layer OSI Model 4

OSI Layer Relationships 5

Application Layer (7) Topmost layer Represents services that directly support user applications Window to network services Handles network access, flow control, and error recovery 6

Presentation Layer (6) Network translator On sending end, determines formatting used to exchange data among computers and adds formatting so data can be understood by network On receiving end, translates data from application format to a common intermediate format Manages data compression, translation, encryption I/O redirectors work to redirect resources to a server 7

Session Layer (5) Allows two applications on different computers to open, use, and close connections Performs name recognition and provides security Provides synchronization by placing checkpoints in the data stream Implements dialog control between communication processes 8

Transport Layer (4) Sending end: repackages message, divides long messages to ship properly over determined route and arrive error-free Receiving end: unpacks message, reassembles it, and acknowledges receipt Provides flow control, error handling, and solves transmission problems 9

Network Layer (3) Addresses the package using network address scheme Determines the best route on the network based on network conditions, priority of service Performs packet switching, routing, traffic management, and controls congestion of data 10

Data-Link Layer (2) Sending end: sends data frames from network layer to physical layer Receiving end: packages raw bits from physical layer into data frames Parts of data frame: Destination ID, Sender ID, Control Data Acknowledges data frames, error checking, and verification 11

Simple Data Frame 12

Physical Layer (1) Bottommost Layer Hardware-oriented, establishes and maintains physical link between communication computers Defines how the cable is attached to the NIC Packet sent as an unstructured raw bit stream over physical medium Referred to as the “hardware layer” 13

OSI Model Layer Mnemonics 14 OSI Layer Down Up

Packet Assembly and Disassembly Process 15

Windows NT and OSI 16

Software and Protocols 17

Windows NT Architecture with Boundary Interfaces 18

The IEEE 802.x Standard 19 The 802 Project Model

802 Specifications Set Standards for: Network Interface Cards (NICs) Wide area network (WAN) components Components used to create twisted-pair and coaxial cable networks 20

802 Specification Categories 802.1Internetworking 802.2Logical Link Control (LLC) 802.3MAC layer, Carrier Sense Multiple Access with Collision Detection (CSMA/CD) LAN (Ethernet) 802.4MAC layer, Token Bus LAN 802.5MAC layer, Token Ring LAN 802.6Metropolitan area Network (MAN) 802.7Broadband Technical Advisory Group 802.8Fiber-Optic Technical Advisory Group 802.9Integrated Voice/Data Networks Network Security Wireless Network Demand Priority Access LAN, 100BaseVG-AnyLAN Unused Cable modem standards Wireless personal area networks (WPAN) Broadband wireless standards 21

Project 802 LLC and MAC Sublayers 22

Project 802 LLC and MAC Standards 23

Device Drivers and OSI 24 Role of Drivers Network Environment Network Driver Interface Specifications (NDIS) Open Data-Link Interface (ODI) Bridging NDIS and ODI

Role of Drivers Drivers for nearly every type of device including: Input devices, such as mouse and keyboard devices SCSI and IDE disk controllers Hard and floppy-disk drives Multimedia devices such as microphones, cameras, and recorders Network Interface Cards (NICs) Printers, plotters, tape drives, and so forth 25

Communication Between the NIC and Network Software 26

Network Driver Interface Specification (NDIS) Three types of network software: Protocol Stack: Provides network communications; generates and disassembles frames that are sent to and received from network Adapter Driver: Controls network interface hardware; works in MAC sublayer and moves frames between protocol stack and interface hardware Protocol Manager: Controls activity between protocol stack and MAC 27