Types of WAN

TYPES OF WAN :: (TECHNOLOGIES OF WAN) IMP

using components such as bridges & routers etc , lan can be expanded to wan

  1. CIRCUIT SWITCHING ::

''Dedicated communications path established for the duration of a connection.''

i.e to select one way from many ways & switch over to that part .

LOGICAL PATH :: all the routs available from source to destination

DEDICATED PATH :: the way which we select outof all logical paths s known as dedicated path

source————–nodes/stations——-destinations..

data is transferred from source to 1st node where it is checked for errors, if that data is fine then it's transferred to next node & a copy of it is kept here on 1st node (for if data become corrupted on 2nd node )…but if the data is corrupted on 1st node then it s moved back to the source for correcting that…e,g telephone network

  1. PACKET SWITCHING ::

data s trasferred on dedicated path in form of packets/chunks of variable (different)size.

every packet is data by it self..data packet is transferred to node then it decided where it will go

then all packets r receieved

at destination & r oredered

wth every data packet 12 bits r attached on each side of packet ..1st 12 bits r known as header

last 12 bits r known as trailer

these 12 bits contain :: source info , dest info , error checking

theses two 12 bits makes data tranfer slow the max speed is 64 kb

e,g terminal to computer & computer to computer communications.

  1. FRAME RELAY ::

only ist packet will have header & the last packet of trailer ..attaching a 8-12 bit overhead to every packet maked data trasferr rate very slow so in frame relay was made .it's also a packet-switiching network service but the advancement was that it used fiber-optic networks.12mb(bits)ps..

  1. ATM (ASYNCHRONOUS TRANSFERR MODE)

same rule as frame relay & packet switching

but the size of packets would be of equal size & they would be called cells not chunks  ,,,max speed 10 -100 mb/s

synchronous means : when 2 things have same speed & time period

  1. ISDN ::integrated services digital network

data & telephone r integrated on same line one connection speed no busy signal

two types r ::::

narrow band  : 64 kbps

broad band : 100 kbps

FDDI : FIBER DISTRIBUTED DATA INTERFACE

SONET : SYNCHRONOUS OPTICAL NETWORK..uses fiber optic technology , more than 1Gbps.

SMDS : SWITCHED MULTIMEGABIT DATA SERVICE…uses the fixed length cell relay technology as ATM..