INTERNATIONAL  TELECOMMUNICATION  UNION

		     ITU-T RECOMMENDATION SUMMARY


Rec. No. : E.491

Title :	Traffic measurement by destination

Study Group : II - Network operation

Version : New

Date of adoption : 1992

Notes :	


Traditionally, traffic measurements for network planning and other 
purposes have been taken on a circuit group basis. These measurements 
could be used directly for circuit group administration, and, for 
hierarchical networks, could be combined with pre-defined routing 
information to approximate point-to-point traffic matrices.

However, these measurements do not allow accurate evaluation of 
end-to-end blocking, and thus, do not reflect the Quality of Service 
perceived by customers.

In addition, with widespread use of network management controls and 
dynamic routing where the concept of final trunk groups vanishes, 
destination-based measurements are required to allow evaluation of 
network performance and Quality of Service.

The use of destination-based traffic measurements can be beneficial in 
all three cycles of network operations which are described in 
Recommendation E.490. Because service problems are identified 
directly, trunk group additions and adjustments become 
straightforward and so do network traffic management actions.

It should be noted that the advent of multi-service integrated 
networks will require that data measured on a destination basis be 
further split into classes of service. This will be necessary in order 
to ensure service specific performance objectives in an environment 
where each service has its own traffic characteristics.

Recommendation E.491 outlines two approaches to destination-based 
measurements and defines the operational layers to which they each 
apply.



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