ITG Engineering Guidelines Page 75 of 378
ITG Trunk 2.0 ISDN Signaling Link (ISL) Description, Installation and Operation
A good design of the ITG network must begin with an understanding of
traffic, and the underlying network that will transmit the traffic. There are
three preliminary steps that you must undertake.
1Calculate ITG traffic. The tech nici an must es timate the amoun t of traf fic
that the Meridian 1 system will route through the ITG network. This in
turn will place a traffic load on the corporate intranet. This is described
in “ITG traffic engineering” on page76
2Assess WAN link resources. If resour ces in the corporate intranet are not
enough to adequately support voice serv ices, it i s normally caus ed by not
enough WAN resources. “Assess WAN link resources” on page 101
outlines how this check can be made.
3Measure existing int ran e t's Quality of Service (Qo S ) . Th e te ch n i ci an
must estimate th e quality of voic e service the corp orate intranet can
deliver. “Measure intranet QoS” on page114 describes how to measure
prevailing delay and error characteristics of an intranet.
After the assessment phase, you can design and implement the ITG network.
This design not only involves the ITG elements, but can also require making
design changes to the existing customer intranet. “Fine-tune Network QoS”
on page 119 and “Implement QoS in IP networks” on page126 provides
guidelines for making modifications to the intranet.