Transcript Communications Protocols (continued)

Network Connectivity
Guide to Operating Systems
Third Edition
Objectives
After reading this chapter and completing
the exercises you will be able to:
• Explain networking basics
• Describe network transport and communications
protocols
• Explain how to integrate different operating
systems on the same network
• Describe how operating systems are used for
remote networking
Guide to Operating Systems, Third Edition
2
Networking Basics
• Network
– system of computing devices, computer resources,
information resources, and communication devices
– linked with cables or wirelessly
• The basic principle of networking is similar to
connecting telephones for communications
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Networking Basics
(continued)
• Hardware
– computers, printers, communications cable
– internetworking devices such as bridges, switches,
routers, and hubs
• Software
– client and server network operating systems
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Networking Basics
(continued)
• Client operating system
– run applications, process information, and
communicate over the network
– Windows 98, Windows NT 4.0 Workstation,
Windows 2000 Professional, and Windows XP
Professional
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Networking Basics
(continued)
• Workstation
– CPU and can run applications locally, or obtain
applications and files from another computer on
the network
• Terminal
– no CPU or local storage for running programs
independently
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Networking Basics
(continued)
• Server Operating System
– network operating system (NOS) that coordinates
network activities and the sharing of resources
• Remote Installation Services (RIS)
– install pre-configured client operating systems,
such as Windows XP, on a mass scale
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Networking Basics
(continued)
• Publishing an application
– installing custom configured software from a central
server
• Assigning applications
– Enables a client to automatically start a particular
version of software through a desktop shortcut or
menu selection, or by clicking a file type
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The Development of
Network Operating Systems
• UNIX
– first operating system designed for networks
• Novell NetWare
– one of first commercial operating system to
emphasize network capabilities
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The Development of
Network Operating Systems
(continued)
• Windows 3.11
– Windows for Workgroups (WFW)
– connects to NetWare, Microsoft, and other servers
• Workgroups
– pre-defined groups of member computers
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The Development of
Network Operating Systems
(continued)
• Windows 95
– expanded peer-to-peer networking capabilities
• Windows Me
– better networking capabilities for home use
• Windows NT 3.1
– intended for industrial strength networking from the
beginning
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The Development of
Network Operating Systems
(continued)
• Windows 2000
– Server and Professional (Workstation)
• Windows 2000/XP/Server 2003
– contain the core elements of Windows 2000 kernel
– home and small office networking
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Local and Wide Area
Networks
• Local area network (LAN)
– one in which the service area is relatively small or
one spread throughout a floor in a building
• Wide area network (WAN)
– one that offers networking services over a long
distance, such as between cities, states, or
countries
Guide to Operating Systems, Third Edition
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Network Topologies
• Topology
– physical design of the network
• Bus topology
– designed like a climbing rope with knots tied along
the way for a foothold
– beginning and end to the rope, and junctures along
the way for your feet
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Network Topologies
(continued)
• Ring topology
– one in which the data-carrying signal goes from
station to station around the ring
– no beginning or end point
• Star topology
– one in which there is a hub in the middle, with cable
segments coming out of the hub in all directions
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Networking Hardware
• Network interface card (NIC)
– used to computers and other devices connected to a
network
– unique hexadecimal address, called a device or
physical address
– also called Media Access Control (MAC) address
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Networking Hardware
(continued)
• Firmware
– software logic on the NIC
– communication between the operating system and its NIC is
controlled by driver software
• “Guided” media
– twisted-pair cable
– fiber-optic cable
• “Unguided” media
– air
– space
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Networking Hardware
(continued)
• Twisted-pair cable
– one or more pair of twisted copper
– UTP-unshielded twisted pair
• Coaxial cable
– more expensive than UTP
– original standard but not often used now
• Fiber-optic cable
– glass or plastic transmitting signals with light
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Networking Hardware
(continued)
• Hub
– common device to connect devices to a LAN
– transmits to all segments
• Switches
– intelligent hub
– transmits only to the destination segment
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Networking Hardware
(continued)
• Wireless access point
– connects wireless devices to a wired network
• Bridge
– used to link segments that are close together
– extend segments
– promiscuous mode
• Routers
– used to join networks, either locally or remotely
– look at routing information in packets before forwarding those
packets to another network
Guide to Operating Systems, Third Edition
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Packets, Frames, and Cells
• Each data unit is called a packet or frame
– terms are sometimes used interchangeably, but they
are not the same
– both consist of data and transmission control
information contained in a header
– packet contains routing information
• Data is placed after the header information, and
followed by a footer or trailer that enables detection of
a transmission error
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Packets, Frames, and Cells
(continued)
• Transmission
– older networks transmit at 4 Mbps (megabits per
second), 10 Mbps, and 16 Mbps
– newer networks transmit at 100 Mbps to 10 Gbps
and faster
• Cell
– data unit designed for high-speed communications
• Payload
– portion of a frame, packet, or cell that contains the
actual data
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Packets, Frames, and Cells
(continued)
• One element of the cell header is path information that
enables the cell to take the route through the network
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Networking Protocols
• Protocol
– set of formatting guidelines for network
communications
– coordinate network communications
– network may use several different protocols
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Networking Protocols
(continued)
• Protocols are used for many types of network
communications:
– Coordinating transport of packets and frames
– Encapsulating data and communication control
information
– Providing communications to accomplish a specific
function
– Enabling communications over a long-distance
network
– Enabling remote users to dial into networks
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Transport Protocols
• Common transport protocols
– Ethernet
– token ring
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Transport Protocols
(continued)
• Ethernet
– one station on the network transmits at a given time
– If two or more stations transmit at the same time,
frames collide
– transmission control method used by Ethernet is
called Carrier Sense Multiple Access with Collision
Detection (CSMA/CD)
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Transport Protocols
(continued)
• Ethernet networks are designed in a bus or star
topology
• Fast Ethernet
– commonplace
– handle either 10 or 100 Mbps communications
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Transport Protocols
(continued)
• Ethernet versions are compatible with popular
network operating systems such as:
– UNIX
– NetWare
– Windows NT, Windows 2000, and Windows Server
2003
– Windows 98/Me
– Windows XP
– Mac OS
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Transport Protocols
(continued)
• Token ring
– one network station transmits at a time
– transmissions are controlled by the use of a
specialized frame, called a token
– transmitted around the network until it is captured
by a station that wants to transmit
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Transport Protocols
(continued)
• Wireless network
– described by it MAC (medium access control)
protocol
– carrier sense multiple access with collision
avoidance (CSWMA/CA)
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Transport Protocols
(continued)
• Network Device Interface Specification (NDIS)
– Microsoft designed
• Open Datalink Interface (ODI)
– Novell designed
• NIC cable interface
– match the type of cable used on the network
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Communications Protocols
• Communications protocols
– protocols that carry data between two stations
• Internet Packet Exchange (IPX) protocol
– developed to enable a NetWare file server to
communicate with its client workstations
– encapsulates data and transports it within a host
transport protocol
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Communications Protocols
(continued)
• ARPANET, the long-distance network that set
the foundation for the Internet
– Transmission Control Protocol (TCP)
– Internet Protocol (IP)
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Communications Protocols
(continued)
• Sequence Packet Exchange (SPX)
– protocol that provides connection-oriented
communications
– IPX relies upon SPX to provide reliable, error-free
communication
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Communications Protocols
(continued)
• IPX works with other specialized service and
NetWare protocols as follows:
– Link Support Layer (LSL)
– NetWare Core Protocol (NCP)
– NetWare Link Services Protocol (NLSP)
– Routing Information Protocol (RIP)
– Service Advertising Protocol (SAP)
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Communications Protocols
(continued)
• NetBEUI (NetBIOS Extended User Interface)
– introduced in the early nineties as the main
protocol for LAN Manager
– Microsoft does not support in Windows XP and
Windows Server 2003
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Communications Protocols
(continued)
• TCP/IP
– one of the oldest protocols
– UNIX always used TCP/IP
• TCP
– developed for extremely reliable point-to-point
communications
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Communications Protocols
(continued)
• TCP communication functions :
– Establishes the communication session between
two computers
– Ensures that data transmissions are accurate
– Encapsulates, transmits, and receives the payload
data
– Closes the communication session between two
computers
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Communications Protocols
(continued)
• The IP makes sure that a frame or packet
reaches the intended destination
• IP functions with TCP:
– Handles packet addressing
– Handles packet routing
– Fragments packets
– Provides simple packet error detection
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Communications Protocols
(continued)
• IP addressing
– dotted decimal notation
– Class A through Class E
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Communications Protocols
(continued)
• Unicast
– one copy of each packet is sent
• Multicast
– recipients are placed in a group
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Communications Protocols
(continued)
• Class A networks
– are identified by a value between 1 and 126 in the
first position of the dotted decimal address
• Class B
– unicast addressing format for medium-sized
networks composed of up to 65,536 nodes
– identified by the first octet of bits ranging from
decimal 128 to 191
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Communications Protocols
(continued)
• Class C
– addresses are used for unicast network
communications on small networks of 256 nodes or
less
– range of 192 to 223
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Communications Protocols
(continued)
• Class D
– do not reflect the network size, only that the
communication is a multicast
– the four octets are used to specify a group of nodes
to receive the multicast
– range from 224.0.0.0 to 239.255.255.255
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Communications Protocols
(continued)
• Class E
– is used for experimentation, and addresses range
from 240 to 255 in the first octet
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Communications Protocols
(continued)
• Classless Interdomain Routing (CIDR)
– new way of addressing that puts a slash (/) after the
dotted decimal notation
– provides more IP address options for medium-sized
networks
– there is shortage of Class B and Class C addresses
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Communications Protocols
(continued)
• Subnet mask
– enables identification of smaller networks within the
larger setup
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Communications Protocols
(continued)
• Some protocols include the following:
– Routing Information Protocol (RIP)
– Simple Mail Transfer Protocol (SMTP)
– File Transfer Protocol (FTP)
– Telnet
– Hypertext Transfer Protocol (HTTP)
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Communications Protocols
(continued)
• Some protocols include the following:
– Point-to-Point Protocol (PPP)
– Simple Network Management Protocol (SNMP)
– Internet Control Message Protocol (ICMP)
– Domain Name Service (DNS)
– Dynamic Host Configuration Protocol (DHCP)
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Communications Protocols
(continued)
• AppleTalk
– protocol used between Macintosh computers
– peer-to-peer protocol
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Communications Protocols
(continued)
• Essential services
– remote access to files over a network
– network print services
– access to computers running MS-DOS or Windows
operating systems
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Communications Protocols
(continued)
• AppleTalk protocols:
– AppleTalk Address Resolution Protocol (AARP)
– AppleTalk Data Stream Protocol (ADSP)
– AppleTalk Session Protocol (ASP)
– Datagram Delivery Protocol (DDP)
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Communications Protocols
(continued)
• AppleTalk protocols (continued):
– Name-Binding Protocol (NBP)
– Printer Access Protocol (PAP)
– Routing Table Maintenance Protocol (RTMP)
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Implementing Communications
Protocols in an Operating System
• Computer operating systems are designed to
support one or more communications
protocols
• Steps involved in setting up communications
protocol
– install the protocol software that is written for that
operating system
– bind the protocol with the NIC
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Implementing Communications
Protocols in an Operating System
(continued)
• Mac OS X Network panel:
– Configuration of IP address and subnet mask
– Automatic configuration of IP address using DHCP
– Identification of the nearest router by IP address
– Identification of Domain Name Service (DNS) servers
by IP address
– Identification of search domains by IP address
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Implementing Communications
Protocols in an Operating System
(continued)
• Most UNIX systems have TCP/IP networking
support built in
• UNIX/Linux
– configure a loopback device
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Implementing Communications
Protocols in an Operating System
(continued)
• Red Hat Linux GNOME interface
– configure a network connection by clicking the Start
icon on the panel, pointing to Programs, pointing to
System, and clicking Network Configuration
• NetWare
– IPX and TCP/IP can be set up in a window that
appears when NetWare is installed
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Implementing Communications
Protocols in an Operating System
(continued)
• Communications
protocols are set
up in Windows
95/98/Me and
Windows NT 4.0
through the
Network icon in
the Control Panel
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Integrating Different
Operating Systems on the
Same Network
• Key to implementing multiple operating systems
on one network
– select a transport protocol and communications
protocols that are supported in all of the operating
systems
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Using Operating
Systems for Dial-Up Access
• Remote Access Services (RAS) server
– dialing into a LAN
– network services that can be installed
– Point-to-Point Protocol (PPP)
– Point-to-Point Tunneling Protocol PPTP)
– Serial Line Interface Protocol (SLIP)
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Using Operating
Systems for Dial-Up Access
• Security
– very important topic because of potential
threats from viruses or hackers
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Using Operating
Systems for Dial-Up Access
• Authentication
– way you identify and validate who you are to the
server
• Encryption
– encoding of the data between you and the server
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Summary
• Network is a system of information resources
and productivity tools
• Invented because they enable users to share
information and information resources over
short and long distances
• Networks are designed in standardized
topologies (bus, star, and ring)
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Summary (continued)
• Standardized communication means
– frames, packets, and protocols
• Protocols act as a common language for
communications
• Modern operating systems use TCP/IP and
IPX/SPX
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Summary (continued)
• Bridges, switches, and routers can be
employed for network security
• LANs are smaller networks
• WANs are long-distance networks
• Dial-up access with communications
protocols, such as SLIP and PPP
• PPP is most commonly used because it
can transport a combination of protocols
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