Upload
dorthy-berry
View
213
Download
0
Embed Size (px)
Citation preview
1© 2001 John Urrutia. All rights reserved.
Chapter 7
Networking Networking and theand theInterNetInterNet
2© 2001 John Urrutia. All rights reserved.
TopicsBackground
Common Types of Networks
Communications Over the Network
Networking Utilities
Distributed Computing
3© 2001 John Urrutia. All rights reserved.
Topics (cont.)Nertwork Services / DAEMONS
InterNet Services
The World Wide Web
Creating your own Web Page
4© 2001 John Urrutia. All rights reserved.
BackgroundSneaker-Net (pre-tty)
Slow
Unreliable transmission
Serial transmissionFaster than slow (100’s BPS)
More reliable
5© 2001 John Urrutia. All rights reserved.
BackgroundMost companies run several
networks in their environmentLAN, MAN, WAN
Intranet – Link company infrastructure
Internet – Link the company to the outside world
Fast – (10’s MBS – 1 GBS)
6© 2001 John Urrutia. All rights reserved.
BackgroundNetwork services
Linux runs special processes called daemons
These are continually running processes that handle the sharing of system resources such as file systems
They make remote file systems appear as attached to local computers
7© 2001 John Urrutia. All rights reserved.
BackgroundNetwork services
New utilities developed to handle the networked environment
rwho – rlogin – telnet – rcp – ftp
8© 2001 John Urrutia. All rights reserved.
BackgroundIntranets
Access is restricted to internal users.
Similar to LANs but uses internet protocol and technology.
Provides Inter-operability (Macs, PC, Linux, etc.)Local e-mail Web-page development and access
9© 2001 John Urrutia. All rights reserved.
TopicsBackground
Common Types of Networks
Communications Over the Network
Networking Utilities
Distributed Computing
10© 2001 John Urrutia. All rights reserved.
Common Types of NetworksNetwork topologies – Broadcast
Ethernet
Single wire – Party line
All systems have access to all traffic
Messages sent at will
Collisions require re-sends which can cause network instability
11© 2001 John Urrutia. All rights reserved.
Common Types of NetworksNetwork topologies – Token ring
FDDI –Fiber Distributed Data Interface
Single wire – Party line
All systems have access to all traffic
Messages sent only when token captured
Token passing can fail which cause delays in network traffic
12© 2001 John Urrutia. All rights reserved.
Common Types of NetworksNetwork topologies – Point to point
Two endpoints only
Dedicated line between points
Well governed – limited traffic
Topologically limited to small number of connections (2 log N )
13© 2001 John Urrutia. All rights reserved.
Point to Point
14© 2001 John Urrutia. All rights reserved.
Common Types of NetworksLocal Area Networks ( LANs)
Run over:Thicknet (Coaxial cable) or Thinnet
(10BASE2) Unshielded Twist Pair
UTP, Category 5, 10BASET Fiber Optic Cable Infrared Radio
15© 2001 John Urrutia. All rights reserved.
Common Types of NetworksLocal Area Networks ( LANs)
Designed to support a small network within a small geographical areaOfficeStoreHome
16© 2001 John Urrutia. All rights reserved.
Common Types of NetworksEthernet
Ethernet technology runs at 10MBS but throughput is less do to collisions
Messaging is processed by packets. Each of which contain a destination address
Ethernet ImprovementsAllow up to 1GBS over UTP
17© 2001 John Urrutia. All rights reserved.
Common Types of NetworksFDDI
Peak data rate is 100MBS
DrawbacksCost of CableCost of interface cardsDifficult to install and maintain
Technology Available over copper
18© 2001 John Urrutia. All rights reserved.
Common Types of NetworksWide Area Networks ( WANs)
Designed to cover a large geographic area. Across states or countries or around the
world
Generally Point-to-PointLeased linesSatellite
19© 2001 John Urrutia. All rights reserved.
Common Types of NetworksMetropolitan Area Networks ( MANs)
Designed to cover a medium geographic area. Across buildings or within a city
Generally Point-to-PointLeased linesRadio
20© 2001 John Urrutia. All rights reserved.
Common Types of NetworksGateways
Allow interoperability across disparate hardware devices or networks.
Translates protocols from LAN to WAN
Re-packets messages
21© 2001 John Urrutia. All rights reserved.
Common Types of NetworksRouters
Hi speed switching station connecting 2 or more networks
Constantly monitor traffic across the networks
Route datagrams (messages) to the least used pathway
22© 2001 John Urrutia. All rights reserved.
23© 2001 John Urrutia. All rights reserved.
Common Types of NetworksNetwork Protocols
Protocol is the set of rules defining how systems or networks communicate with each otherEthernet, Telnet, FTP, TCP– Transport Control Protocol HTTP – Hyper-Text Transfer Protocol PPP – Point to Point Protocol SLIP – Serial Line Internet Protocol
24© 2001 John Urrutia. All rights reserved.
Common Types of NetworksHost Addresses
Every message sent over the network has a 32 bit destination address (IPv4). Using the Internet Protocol the address is made up of 4 bytes of data
Addresses may be static or dynamic
Addresses are contolled by the NICNetwork Information Center
25© 2001 John Urrutia. All rights reserved.
Common Types of NetworksHost Addresses
Addresses belong to 1 of 4 classes A,B,C,DIdentified by the number of 1 bits in the
highorder byte
The max number of networks allowed on the Internet is 2,113,664
The max number of host computers is 3,758,096,400
26© 2001 John Urrutia. All rights reserved.
Host Addresses31 24 23 16 15 8 7 0
0 Netid Host ID
Bit
Class A:
10 Netid Host IDClass B:
110 Netid Host IDClass C:
1110 Multicast addressClass D:
111110 ReservedClass E:
27© 2001 John Urrutia. All rights reserved.
Common Types of NetworksHost Addresses
127.37.16.231 is a valid IP Address but it is hard to remember
The /etc/hosts file provides the fully qualified host name along with a symbolic nickname
Updating symbolics is a daunting taskNIS – Network Information ServiceDNS – Domain Name Services
28© 2001 John Urrutia. All rights reserved.
TopicsBackground
Common Types of Networks
Communications Over the Network
Networking Utilities
Distributed Computing
29© 2001 John Urrutia. All rights reserved.
Communicating Over the Network
Many of the standard communications utilities have been extended to handle remote computing.pine, finger, talk
Some systems do not identify themselves in their prompt.hostname
30© 2001 John Urrutia. All rights reserved.
Communicating Over the Network
Using finger to learn about Remote Usersfinger @Linux2
Provides information about remote system logins.
Querys the network services
finger daemon runs remotely.
31© 2001 John Urrutia. All rights reserved.
Communicating Over the Network
finger the NEIS at USGS to find almost real-time earthquake info
World Wide mail using pine
Talking around the world talk
32© 2001 John Urrutia. All rights reserved.
TopicsBackground
Common Types of Networks
Communications Over the Network
Networking Utilities
Distributed Computing
33© 2001 John Urrutia. All rights reserved.
Networking UtilitiesMany of the utilities have been
extended to provide network access
New utilities created to monitor and control the network environment
34© 2001 John Urrutia. All rights reserved.
Networking UtilitiesUsing rlogin and telnet to
Access Remote Computersrlogin is used to connect UNIX and
UNIX-like systems
telnet is used to connect non-UNIX systems
Both utilities make your host session appear to be on the remote system
35© 2001 John Urrutia. All rights reserved.
Networking UtilitiesYou must be trusted to use rcp rsh
Trusted systems are identified by the /etc/hosts.equiv file.
Trusted Hosts and the ~/.rhost FileIdentifies the host name and user id
36© 2001 John Urrutia. All rights reserved.
Networking UtilitiesUsing ftp to Transfer Files
…]$ ftp linux2ascii / binarygetputbye?
37© 2001 John Urrutia. All rights reserved.
Networking UtilitiesUsing rsh to run commands
remotely
38© 2001 John Urrutia. All rights reserved.
Networking UtilitiesUsing ping to Test a Network
ConnectionUses ICMP – internet control message
protocol
39© 2001 John Urrutia. All rights reserved.
Networking UtilitiesUsing rwho to list Users on Remote
Systems
40© 2001 John Urrutia. All rights reserved.
TopicsBackground
Common Types of Networks
Communications Over the Network
Networking Utilities
Distributed Computing
41© 2001 John Urrutia. All rights reserved.
Distributed ComputingThe Client/Server Model
Servers store and provide information to clients
Clients access information through servers
42© 2001 John Urrutia. All rights reserved.
Distributed ComputingDomain Name Services (DNS)
Hierarchy.com.edu.gov.mil.net.org
43© 2001 John Urrutia. All rights reserved.
Distributed ComputingNetwork Information Service (NIS)
Developed by Sun Microsystems
Keeps system independent configuration files current
Access information throughypcatypmatch
44© 2001 John Urrutia. All rights reserved.
Distributed ComputingNetwork File System (NFS)
Makes available remote file systems as local filesystems
45© 2001 John Urrutia. All rights reserved.
Topics (cont.)Nertwork Services / DAEMONS
InterNet Services
The World Wide Web
Creating your own Web Page
46© 2001 John Urrutia. All rights reserved.
Network Services / DAEMONSInetd
Listens for service requestsAutomatically starts other daemons to
provide services
47© 2001 John Urrutia. All rights reserved.
Network Services / DAEMONSnamed
Supports the DNSThis replaces the old /etc/hosts table
48© 2001 John Urrutia. All rights reserved.
Network Services / DAEMONSin.nntpd
Network News Transfer Protocol
Provide exchange service of USENET articles
Intelligently downloads files
49© 2001 John Urrutia. All rights reserved.
Network Services / DAEMONSrouted
Manages routing tables
gatedManages gateway configurations
50© 2001 John Urrutia. All rights reserved.
Network Services / DAEMONSsmtpd
Simple Mail Transfer Protocol
51© 2001 John Urrutia. All rights reserved.
Topics (cont.)Nertwork Services / DAEMONS
InterNet Services
The World Wide Web
Creating your own Web Page
52© 2001 John Urrutia. All rights reserved.
Internet ServicesUSENET
Formed in the 1980’s
Similar to an electronic bulletin board
53© 2001 John Urrutia. All rights reserved.
Internet ServicesArchie
Public domain database of over 1000 FTP sites
Tell you where to find stuff
54© 2001 John Urrutia. All rights reserved.
Internet ServicesGopher
Retrieves selected documents based on your criteria
55© 2001 John Urrutia. All rights reserved.
Topics (cont.)Nertwork Services / DAEMONS
InterNet Services
The World Wide Web
Creating your own Web Page
56© 2001 John Urrutia. All rights reserved.
Overview of the WWWBrowser terminology
Screen Elements
Navigating the WEB
Reading News
Downloading files
Bookmarks
57© 2001 John Urrutia. All rights reserved.
Overview of the WWWSearch Engines
Alta Vista
LYCOS
Excite
HotBot
58© 2001 John Urrutia. All rights reserved.
Creating Your Own Web PageNetscape
MS Word