3. IT News
Apple – Foxconn – Daisey – TAL
Windows 8
4. Why do we network?
http://www.youtube.com/watch?v=7_LPdtt
KXPc&feature=related
Reduce hardware and software costs
Provide access to a wide range of services
and specialized peripheral devices
Enable people to work together,
regardless of time and place
7. Networks 101
Refresher
– Client/server – contains servers and clients
– Peer-to-peer (P2P) – every computer is
considered an equal
8. Ring Topology
Tree Topology
Star Topology
Bus Topology Mesh Topology
9. Networks 101
A network is a collection of computer
systems configured to share digital data
and resources
Computer to Computer
Local Area Network (LAN)
LANs extend across limited
– geographical area
servers, terminals, etc.
10. How LANs work
Connectivity supporting two-way communication
Resource sharing
Limited geographical area
Transparency of use
Support from hardware and software
Positives
– communications
– management control
– cost-effectiveness
Negatives
– need for additional equipment
– maintenance
– support staff
11. Lots of Networks
LAN (Local Area Network)
WAN (Wide Area Network)
MAN (Metropolitan Area
Network)
PAN (Personal Area Network)
And more – NFC, BAN, NAN,
CAN…
12. Networks
Internetwork:
collection of autonomous networks
Ex: the Internet, intranets
The Internet:
ARPAnet - late 1960s
decentralized
loosely-coupled
redundant
Apps
e-mail
telnet
FTP (file transfer protocol)
www
13. Networks
ARPANET
The ARPANET, created in 1969,
connected computers at four
universities
WWW
Hypertext system
This was an open system, evolved to
I2
14. Networks - Shannon
an information source generates a message
a transmitter encodes the message as a signal
the signal is transmitted over a communications channel
the receiver extracts a signal from the communications
channel and converts it back into the form of a message
the destination receives the message
a source of noise is usually present in the
communication channel—this is a random element that
modifies the signal in unpredictable ways
15. Networks
Messages are encoded as a stream of
binary numbers (0s and 1s)
Signals are transmitted as electro-magnetic
energy (electrical, optical, or radio waves)
Rate of reliable transmissions depends on
the properties of the channel and the
complexity of the message
Two types of signals:
Analog
Digital
16. iSpace Model
CLIENT--(local)
system requesting
services
SERVER--(remote)
system that receives
and handles
requests from many
clients concurrently
17. Peer-To-Peer (P2P)
Another Model: Peer to Peer
Each entity can act as a client or a server
File sharers use this P2P terminology for file
exchanges (ex.: Gnutella, Napster, Grokster,
bittorrent)
P2P (workgroups) - typically <10 people
No central communication control device
Inexpensive
Each computer’s resources are used
19. Bandwidth
Broadband
– multiple signals transmitted on the same channel
simultaneously
– channel is divided into separate frequency bands,
each capable of carrying a signal
Narrowband/baseband
– employs [the entirety of its available] bandwidth
for one signal
20. Bandwidth Terms
The bandwidth of a communications channel
determines its capacity to transmit data—it’s
analogous to the size of plumbing pipes (10MB,
100MB, 1GB, 10GB)
Analog signals may contain independent
waveforms of various frequencies
The number of frequencies supported by a
channel determines its bandwidth
The bandwidth of a digital channel is usually
measured in bits per second (bps)
21. Bandwidth Terms
What affects bandwidth?
media used for transmission of signals
22.
23. Networks 101
Physical layer supports
basic carrier signals
Data link layer manages
point-to-point
connectivity
Network layer routes
data from sender to
destination
Transport layer
provides messaging
services
Application layer
provides user functions
26. Sending Information
When you transmit data, it is broken up into small
pieces called packets
A packet is a parcel of data that is sent across a
network
– Has the address of its sender
– Has the address of the destination
– Has some data
When packets reach their ultimate destination,
they are put back together into the data that was
originally transmitted
27. Sending Information
Data can be sent in two ways:
– Synchronous protocols
– Asynchronous protocols
Handshaking
28. Networking
Packet Switching
– The message is made of separate data packets,
each addressed to the destination
– Packets are transmitted over any available
connection to the destination
– The receiving node reassembles the message
32. Connecting
Modem / Dial-up
– “modem” = modulate-demodulate
Modulation – changing the characteristics of a
signal (digital to analog)
Demodulation – changing the signal back to its
original state (analog to digital)
33. Cables
Most networks use twisted-pair cables
– UTP (unshielded twisted pair)
– STP (shielded twisted pair)
– Looks similar to telephone cable
– Has a square plastic RJ-45 connector
Twisted Pair Wire Cable
– Insulated pairs of wires historically used in
telephone service
• Category 1 – Telephones
• Category 3 – Up to 10Mbps
• Category 5 – Up to 100Mbps
34. Cables
Another option is coaxial cable
– Resembles cable-TV cable
– Round, silver BNC or F-type connector
Coaxial Cable (BNC)
– Consists of an inner conductor wire surrounded by
insulation, called the dielectric. The dielectric is
surrounded by a conductive shield, which is surrounded
by a non-conductive jacket. Coaxial cable has a better
data transmission rate than twisted pair.
35. Cables
Fiber-optic cable is a bundle of extremely
thin tubes of glass
– Many extremely thin fibers of glass or plastic,
coated with a cladding and bound together in a
sheathing which transmits signals with light beams
•Fast transfer rates
•Immune to electrical interference (emi occurs
over long distances)
•Hard to tap into
•Takes less space
– Each optical fiber (tube) is thinner than a human hair
38. Networks
Repeaters
– boost the signal strength over transmission
medium
Bridges
– isolate LANs from unnecessary traffic, but connect
LANs to neighboring networks
Switches?, Routers?, Hubs?
39. Networks
Datagrams:
TCP/IP:
IP address:
Domain names are pseudonyms for IP
addresses
40. Networks
Protocols:
– A communications protocol is a set of rules for efficiently
transmitting data from one network node to another
– The best-known protocol is probably TCP/IP
– Sending Computer:
• Breaks the data into packets; adds addressing
information; prepares the data for transmission
– Receiving Computer:
• Takes packets off the cable; strips the packets of
addressing information; reassembles the data from the
packets
41. Networks
TCP/IP provides a standard that is public,
free, extensible, and fairly easy to
implement. TCP/IP is the glue that holds
the Internet together.
42. Networks
The IP part of TCP/IP defines the format for
the addresses that identify computers on
the Internet
These addresses are called IP addresses
An IP address is a series of numbers, such
as 204.127.129.001
IP addresses
43. Networks
ISPs need static IP addresses
– Clients typically use dynamic IP addresses, as the IP
addressing scheme provides approximately only 4.3
billion unique addresses
Numbers are hard to remember, so host
computers also have names called domain
names; a domain names corresponds to an
IP address; domain name system – huge
database that houses the names and IP
addresses of key computers
Domain name servers – computers that
house this database
44. Networks
Internet 2
– consortium of government, industry, and
education
The consortium
– establishes network capabilities to support
national research
– develops the next generation of Internet
applications
– transfers these to worldwide Internet
45. Networks
Internet 2
– remote instrumentation and virtual laboratories
– distance learning
– digital libraries
– Tele-immersion
– multicasting
46. Networks
National LambdaRail
– High-speed national network running on fiber
– LambdaRail will merge with I2
– Testing service network
– University-based and -owned initiative
47. Networks
Wireless
– infrared broadcasting
– radio frequency
broadcasting
• spread spectrum (cell
telephony)
• direct sequence spread
spectrum (DSSS)
• frequency hopping
spread spectrum (FHSS)
50. Networks
Support for the creation of
802.11a - 54 Mbps standard, 5 GHz signaling (ratified 1999)
802.11b - 11 Mbps standard, 2.4 GHz signaling (1999)
technologies for wireless local
802.11c - operation of bridge connections (moved to 802.1D)
802.11d - worldwide compliance with regulations for use of wireless signal
spectrum (2001)
area networking:
802.11e - Quality of Service (QoS) support (not yet ratified)
802.11F - Inter-Access Point Protocol recommendation for communication
between access points to
support roaming clients (2003)
802.11g - 54 Mbps standard, 2.4 GHz signaling (2003)
802.11h - enhanced version of 802.11a to support European regulatory
requirements (2003)
802.11i - security improvements for the 802.11 family (2004)
802.11j - enhancements to 5 GHz signaling to support Japan regulatory
requirements (2004)
802.11k - WLAN system management (in progress)
802.11l - skipped to avoid confusion with 802.11i
802.11m - maintenance of 802.11 family documentation
802.11n - 100+ Mbps standard improvements over 802.11g (in progress)
802.11o - skipped
802.11p - Wireless Access for the Vehicular Environment
802.11q - skipped
802.11r - fast roaming support via Basic Service Set transitions
802.11s - ESS mesh networking for access points
802.11T - Wireless Performance Prediction - recommendation for testing
standards and metrics
802.11u - internetworking with 3G / cellular and other forms of external
networks
802.11v - wireless network management / device configuration
802.11w - Protected Management Frames security enhancement
802.11x - skipped (generic name for the 802.11 family)
802.11y - Contention Based Protocol for interference avoidance
51. Networks
Using “ping” or “traceroute,” you can
discover the length of time that data is in
transit
On average, data within the US usually
arrives at its destination 110-120
milliseconds (ms) after it is sent
Overseas transmissions require a little
more time
NetTraffic
53. Networks
Network Monitors
– Keep track of network traffic, number of
packets, packet size, collisions, re-
transmissions, etc.
– Enable planning for growth and quality
Network Analyzers
– Randomly dissect packets, analyze problems,
and determine the source of errors
54. Portals
Web entry stations that offer quick and
easy access to a variety of services
– Consumer portals include search engines, e-mail
services, chat rooms, references, news headlines,
shopping malls, and other services
– Corporate portals on intranets serve the
employees of particular corporations
– Vertical portals are targeted at members of a
particular industry or economic sector
Other Web Stuff
– Push (auto-updates) versus Pull (browser in client-
server model) technology
Network topology is the layout pattern of interconnections of the various elements (links, nodes, etc.) of a computer[1][2] or biological network.[3] Network topologies may be physical or logical. Physical topology refers to the physical design of a network including the devices, location and cable installation. Logical topology refers to how data is actually transferred in a network as opposed to its physical design. In general physical topology relates to a core network whereas logical topology relates to basic network
LAN - a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building.[1] The defining characteristics of LANs, in contrast to wide area networks (WANs), include their usually higher data-transfer rates, smaller geographic area, and lack of a need for leased telecommunication lines.WAN - a telecommunication network that covers a broad area (i.e., any network that links across metropolitan, regional, or national boundaries). Business and government entities utilize WANs to relay data among employees, clients, buyers, and suppliers from various geographical locations. In essence this mode of telecommunication allows a business to effectively carry out its daily function regardless of location OFTEN OWNED BY SINGLE CORPMAN - a computer network that usually spans a city or a large campus. A MAN usually interconnects a number of local area networks (LANs) using a high-capacity backbone technology, such as fiber-optical links, and provides up-link services to wide area networks (or WAN) and the Internet.PAN - a computer network used for communication among computerized devices, including telephones and personal digital assistants. PANs can be used for communication among the personal devices themselves (intrapersonal communication), or for connecting to a higher level network and the Internet (an uplink)
Internetwork - the practice of connecting a computer network with other networks through the use of gateways that provide a common method of routing information packets between the networks. The resulting system of interconnected networks is called an internetwork, or simply an internet
In response to the Soviet Union’s launch of Sputnik in 1957, the first artificial satellite, the United States created ARPA (Advanced Research Projects Agency) to help scientists communicate and share valuable computer resourcesWWW was created as a medium for disseminating scientific research; organized by Tim Berners-Lee in 1989Hypertext: Documents with built-in cross-referencing called “hyperlinks”
the Shannon–Hartley theorem tells the maximum rate at which information can be transmitted over a communications channel of a specified bandwidth in the presence of noise.
the Shannon–Hartley theorem tells the maximum rate at which information can be transmitted over a communications channel of a specified bandwidth in the presence of noise.
the Shannon–Hartley theorem tells the maximum rate at which information can be transmitted over a communications channel of a specified bandwidth in the presence of noise.
Bandwidth is the transmission capacity of a communications channelBroadband High-bandwidth communications systems, such as cable TV, are sometimes referred to as Systems with less capacity, such as the telephone system, are referred to as narrowband or baseband
What affects bandwidth?distance or expanse covered by the network,LAN, WAN, InternetworkMedia used for trxn of signalsbounded media (copper wire, co-axial, optical fiber cable)unbounded media (“wireless,” radio frequency waves, cellular networks)
Data can be sent in two ways:Synchronous protocols, which coordinate sending and receiving by using a clock signalAsynchronous protocols, which require the transmitting computer to send a start bit that indicates the beginning of a packetHandshakingHandshaking is a networking process when two computers establish a connection. An example of a handshake is when your modem dialup's to a computer network and agrees on baud rate, error correction and compression protocols. Handshaking usually occurs when packets of data are exchanged between two computers.
Datagrams:packets of data that also contain addressing informationTCP/IP:A suite of protocolsdefine protocols (standards) for how datagrams are packaged and deliveredIP address:a number that is the address of an Internet hostDomain names are pseudonyms for IP addressesDomain name system (DNS) servers provide users with IP numbers for URLs, e-mail addresses, etc.
Datagrams:packets of data that also contain addressing informationTCP/IP:A suite of protocolsdefine protocols (standards) for how datagrams are packaged and deliveredIP address:a number that is the address of an Internet hostDomain names are pseudonyms for IP addressesDomain name system (DNS) servers provide users with IP numbers for URLs, e-mail addresses, etc.
Datagrams:packets of data that also contain addressing informationTCP/IP:A suite of protocolsdefine protocols (standards) for how datagrams are packaged and deliveredIP address:a number that is the address of an Internet hostDomain names are pseudonyms for IP addressesDomain name system (DNS) servers provide users with IP numbers for URLs, e-mail addresses, etc.
An IP address is a series of numbers, such as 204.127.129.001It is separated into four sections by periodsEach section’s number cannot exceed 255Each address requires a total of 32 bits (8 bits per section)128.186.6.14IP addressesDynamic IP address – temporarily assignedStatic IP address – permanently assigned
Internet2 is an advanced not-for-profit United States networking consortium led by members from the research and education communities, industry, and government.[1]In 2009, Internet2 member rolls included over 200 higher education institutions,[2] over 40 members from industry,[3] over 30 research and education network and connector organizations,[4] and over 50 affiliate members.[5]Internet2 operates the Internet2 Network,[6] a next-generation Internet Protocol and optical network that delivers production network services to meet the high-performance demands of research and education, and provides a secure network testing and research environment. In late 2007, Internet2 began operating its newest dynamic circuit network, the Internet2 DCN, an advanced technology that allows user-based allocation of high-capacity data circuits over the fiber-optic network.The Internet2 Network, through its regional network and connector members, connects over 60,000 U.S. educational, research, government and "community anchor" institutions, from primary and secondary schools to community colleges and universities, public libraries and museums to health care organizations.[7]The Internet2 community is actively engaged in developing and deploying emerging network technologies beyond the scope of single institutions and critical to the future of the Internet. These technologies include large-scale network performance measurement and management tools,[8] simple and secure identity and access management tools[9] and advanced capabilities such as the on-demand creation and scheduling of high-bandwidth, high-performance circuits.[10]Internet2 is member led and member focused, with an open governance structure and process.[11] Members serve on several advisory councils,[12] collaborate in a variety of working groups and special interest groups[13] gather at spring and fall member meetings,[14] and are encouraged to participate in the strategic planning process.[15]
National LambdaRail is a 12,000-mile (19,000 km), high-speed national network infrastructure owned and operated by the U.S. research and education community that runs over fiber-optic lines, and is the first transcontinental 10-Gigabit Ethernet network. Its very high capacity (up to 1.6 Tbit/s aggregate), high bandwidth (40 Gbit/s implemented; planning for 100 Gbit/s underway) and high availability (99.99% or more), enable National LambdaRail to support some of the world's most demanding research projects. Users include NASA, the National Oceanic and Atmospheric Administration, Oak Ridge National Laboratory, and over 280 research universities and other laboratories. In 2009 National LambdaRail was selected to provide wide-area networking for U.S. laboratories participating in research related to the Large Hadron Collider project, based near Geneva, Switzerland.
Network MonitorsKeep track of network traffic, number of packets, packet size, collisions, re-transmissions, etc.Enable planning for growth and quality Network AnalyzersRandomly dissect packets, analyze problems, and determine the source of errors
Intranets: self-contained intra-organizational networks that offer e-mail, newsgroups, file transfer, Web publishing, and other Internet-like servicesExtranets: private TCP/IP networks designed for outside use by customers, clients, and business partners of the organization that owns the extranetElectronic data interchange (EDI): a decade-old set of specifications for ordering, billing, and paying for parts and services over private networks