ITG Engineering Guidelines Page 79 of 378
ITG Trunk 2.0 ISDN Signaling Link (ISL) Description, Installation and Operation
where loss level cannot compensate, silence su ppression should be disabled
using the MAT ITG ISDN Trunk Node Properties DSP profile tab codec
options sub-tab. See Step 8 on page203.
Disabling silence suppression approximately double s LAN/WAN bandwi dth
use. Disabling silence suppression consumes more real-tim e on the ITG card.
Table 6 shows the bandwidth requirement when silence suppression is
disabled.
Note that this does not impact the data rate for fax, since it does not have
silence suppression enabled to begin with.
Simultaneous voice traffic with silence suppression
When voice services with multi-channel r equirements are exte nsively used in
an ITG network, such as Conference, Music-on-hold, and
Message-Broadcasting, additional voice traffic peaks to the IP network will
be generated due to the simultaneous vo ice tr affic burst s on mult iple cha nnels
on the same links.
In those cases, even when sile nce s uppr ession is e na bled on th e I TG car d, the
more conservative bandwidth calculations of Table6 with silence
suppression disabled is recommended to calculate the port ion of the
bandwidth requirement that is caused by simultaneous voice traffic.