ITG Engineering Guidelines Page 109 of 378
ITG Trunk 2.0 ISDN Signaling Link (ISL) Description, Installation and Operation
• The Meridi an 1 (includi ng the ITG nodes) interfa ces wit h the end users;
voice services offered by the Meridi an 1 ne ed to meet us er-orient ed QoS
objectives.
• The I TG nodes interface with the intranet; the se r v ice provided by the
intranet is “best- effort delivery of IP packets”, not “ guarantee QoS for
real-time voice t ransport.” The ITG translates the QoS objectives set by
the end-users int o IP-oriented Qo S objectives. The guidelines call t hese
objectives intranet QoS objectives.
Figure 14
Relationship between users and services
Corporate intranet
Meridian 1
ITG
Deliver IP service
Deliver voice/fax
service
- Fall back threshold
- Codec
- Payload size
ITG parameters
User oriented QOS
- Roundtrip conversation delay
- Clipping and dropout
- Audio level
- Echo
Network QOS metrics
- One way delay
- Packet loss
- Silence suppression threshold
- Echo cancellor tail delay size
- Audio gain
Delay variation
- Jitter
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