Local Area Network

144 Pages·2012·7.55 MB·English

by  Farid Faramand Local

Local Area Network
Dr. Farid Farahmand
Revised on: 10/6/12
Data Network Areas
WAN (Wide Area Networks)
o 
MAN (Metropolitan Area Networks)
o 
LAN (Local Area Networks)
o 
Sharing resources in small but geographically dispersed network
n
LAN Applications
backend networks
o 
personal computer LANs
o 
interconnecting large systems
n 
low cost
n  (mainframes and large storage devices)
n  limited data rate o  high data rate
n  share resources o  high speed interface
o  printers, hard drives, etc. o  distributed access
n  Potential issues for a single LAN o  limited distance
o  reliability o  limited number of devices
o  capacity o  backbone LANs
o  cost n  interconnect low-speed LANs
o  High-speed office networks n  Resolve typical drawbacks to LANs
used particularly for desktop image
n 
processing
a single page with 200 pictures
o 
elements (black and white) is about
LAN Backbone LAN
3 Mbits!
high capacity local storage
n
LAN Applications
storage area networks (SANs)
o 
separate network to handle storage needs
n 
à shared storage
o 
detaches storage tasks from specific servers
n 
shared storage facility
n 
eg. hard disks, tape libraries, CD arrays
o 
accessed using a high-speed network
n 
eg. Fibre Channel
o 
improved client-server storage access
n 
direct storage-to-storage communication for backup
n 
Project: Build a SAN!
Storage Area Networks
LAN Topologies
Mesh Topology
o  Mesh
n  Devices are connected with many redundant
interconnections between network nodes.
n  In a full mesh topology every node has a connection to
every other node in the network.
Star Topology
o 
n  All devices are connected to a central switch/hub/repeater.
Nodes communicate across the network by passing data
through the switch/hub
n  Typically has unidirectional links
Bus Topology
o 
n  All devices are connected to a central cable, called the bus
or backbone.
n  The bus is often terminated on both ends if not connected
to any devices.
n  The bus is typically duplex.
Ring Topology
o 
n  All devices are connected to one another in the shape of a
closed loop, so that each device is connected directly to
two other devices, one on either side of it.
n  Closed loop with unidirectional links (links are point-to-
point)
o  Tree Topology Tree
n  A hybrid topology. Groups of star-configured networks
are connected to a linear bus backbone.
http://www.webopedia.com/quick_ref/topologies.asp
Frame Transmission
Frame is absorbed
Frame is removed when it returns to
Its source
Ethernet – General
Most common LAN technology allowing multiple
o 
devices to connect to each other and share resources
Developed by Xerox in 1970
o 
Also known as IEEE 802.3
o 
IEEE 802.3 Energy Efficient Ethernet Study Group
n 
Each standards organization focuses on particular layers
o 
of the protocol stack

Institute for Electrical and Electronic Engineers (IEEE)
n 
World Wide Web Consortium (W3C)
n 
Internet Engineering Task Force (IETF)
n
Various Standard Emphasis
- Institute for Electrical and Electronic Engineers (IEEE)
- World Wide Web Consortium (W3C)
- Internet Engineering Task Force (IETF)
Other Standardization Bodies
Institute of Electrical and Electronics
o 
Engineers (IEEE)
The European Computer Manufacturers
o 
Association (ECMA)
The International Electrotechnical
o 
Commission (IEC)
The International Organization for
o 
Standardization (ISO).