Codec Complexity
Codec complication refers to the bulk of processing appropriate to accomplish articulation compression.
Codec complication affects alarm body (that is, the cardinal of calls reconciled
on the DSPs). With college codec complexity, beneath calls can be handled. Select a higher
codec complication back that is appropriate to abutment a accurate codec or aggregate of
codecs. Select a lower codec complication to abutment the greatest cardinal of articulation channels,
provided the lower complication is accordant with the accurate codecs in use.
Cisco DSP assets use one of two types of chipsets, the earlier C549 DSPs and the
newer C5510 DSPs. Table 2-8 illustrates the complication modes the C549 chipset needs
to run to abutment a array of codecs.
Table 2-8 C549 Codec Complexity
Medium Complication (4 calls/DSP) Aerial Complication (2 calls/DSP)
G.711 (a-law and mu-law) G.728
G.726 (all versions) G.723 (all versions)
G.729a, G.729ab (G.729a Annex B) G.729, G.729b (G.729-Annex B)
Fax broadcast Fax relay
Some codec compression techniques crave added processing ability than others. For example,
■ Average complication allows the C549 DSPs to action up to four voice/fax broadcast calls
per DSP and the C5510 DSPs to action up to eight voice/fax broadcast calls per DSP.
■ Aerial complication allows the C549 DSPs to action up to two voice/fax broadcast calls per
DSP and the C5510 DSPs to action up to six voice/fax broadcast calls per DSP.
The aberration amid average and aerial complication codecs is the bulk of CPU utilization
necessary to action the codec algorithm, and therefore, the cardinal of articulation channels
that can be accurate by a distinct DSP. For this reason, all the average complication codecs
can additionally be run in aerial complication mode, but beneath (usually about half) of the channels
are accessible per DSP.