6. ATM
WWW page:
http:/www.dcs.napier.ac.uk/~andrea
4
4
6
6
7
User 1
User 3
User 2
VCI=12
VCI=06
VCI=22
VCI=10
VCI=15
IN
OUT
12
06
Routing table
IN
OUT
06
22
Routing table
6.1 ATM (Asynchronous Transfer Mode) Overview
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Example traffic profile
for speech signal
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
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0.9
1
Example traffic profile
for computer-type data
ATM copes with real-time traffic with:
Analysing the type of connection to be made. The type of data
dictates the type of connection; for example, computer data
requires a reliable connection, whereas real-time sampled data
requires a connection with a low propagation time.
Analysing the type of data to be transmitted and knowing its
traffic profile. Computer data tends to create bursts of traffic
whereas real-time data will be constant traffic.
Reserving a virtual path for the data to allow the data profile to be
transmitted within the required quality of service.
Splitting the data into small packets which have the minimum
overhead in the number of extra bits. These ‘fast-packets' traverse
the network using channels which have been reserved for them.
ATM copes with real-time traffic with:
Analysing the type of connection to be made. The type of data
dictates the type of connection; for example, computer data
requires a reliable connection, whereas real-time sampled data
requires a connection with a low propagation time.
Analysing the type of data to be transmitted and knowing its
traffic profile. Computer data tends to create bursts of traffic
whereas real-time data will be constant traffic.
Reserving a virtual path for the data to allow the data profile to be
transmitted within the required quality of service.
Splitting the data into small packets which have the minimum
overhead in the number of extra bits. These ‘fast-packets' traverse
the network using channels which have been reserved for them.
Ethernet/FDDI/Token Ring are not suited to
real-time traffic as:
There is no guarantee that the connection can
support a given Qua