Hardware Software Systems and Networks CE0300-1

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Oct 24, 2013 (3 years and 7 months ago)

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WAN Protocols

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Copyright 2004 Asia Pacific Institute of Information Technology

Hardware Software Systems and Networks


CE0300
-
1

Degree


Level 1

WAN Protocols

HSSN

Slide
2

of 20


Topic & Structure of the lesson


Circuit Switching


Packet Switching


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HSSN

Slide
3

of 20


Learning Outcomes


At the end of this session you should be able
to:
-


Explain packet switching networks


Explain circuit switching networks



WAN Protocols

HSSN

Slide
4

of 20




Key terms you must be able to use


If you have mastered this topic,
you should be
able to use the following terms correctly in your
assignments and exams
:
-



Route



Buffered



Node





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HSSN

Slide
5

of 20


WAN Protocols


Geographic Classification


LAN are within a building or a campus


WAN can be global


Ownership


LAN mostly owned by the same organisation


WAN include third party equipment & services


Level of Technology


MAN are the most sophisticated

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HSSN

Slide
6

of 20


WAN Protocols


Long distance transmission is typically done over a network of
switched nodes


Nodes not concerned with content of data


End devices are stations (phone, computer, etc.)


A collection of nodes and connections is a communications
network


Data routed by being switched from node to node

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7

of 20


WAN Protocols


Nodes may connect to other nodes only, or to stations and
other nodes


Node to node links usually multiplexed


Network is usually partially connected


Some redundant connections for reliability


Two different switching technologies


Circuit switching


Packet switching


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HSSN

Slide
8

of 20


WAN Protocols

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9

of 20


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Dedicated communication path between two stations


Three phases


Establish Connection


Transfer Data


Disconnect


Must have switching capacity and channel capacity to establish
connection


Must have intelligence to work out routing

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HSSN

Slide
10

of 20


WAN Protocols


Inefficient


Channel capacity dedicated for duration of
connection


If no data, capacity wasted


Set up (connection) takes time


Once connected, transfer is transparent


Developed for voice traffic (phone)

WAN Protocols

HSSN

Slide
11

of 20


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12

of 20


WAN Protocols


Circuit switching designed for voice


Resources dedicated to a particular call


Much of the time a data connection is idle


Data rate is fixed (
both ends must operate at the
same rate
)

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13

of 20


WAN Protocols


Data transmitted in small packets


Longer messages split into series of packets


Each packet contains a portion of user data plus
some control information.


Control information


Routing (addressing) information


Packets are received, stored briefly (buffered) and
past on to the next node (
store and forward
)

WAN Protocols

HSSN

Slide
14

of 20


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15

of 20


WAN Protocols


Line efficiency


Single node to node link can be shared by
many packets over time


Packets queued and transmitted as fast as
possible


Packets are accepted even when network is
busy


Delivery may slow down

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Slide
16

of 20


WAN Protocols


Data rate conversion


Each station connects to the local node at its
own speed


Nodes buffer data if required to equalize rates


Priorities can be used.

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HSSN

Slide
17

of 20



Quick Review


Explain Circuit Switching technology.



List two (2) disadvantage of Circuit Switching.



List four (4) advantage of Packet Switching.



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18

of 20



Summary of Main Teaching Points


Two different technologies that exist is packet
switching and circuit switching.



Long distance communication is usually done
switched nodes.


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of 20


Q & A

Question and Answer Session

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HSSN

Slide
20

of 20


What we will cover next


Networking


WAN Protocols 2