Technical data

Architecture and System Requirements

EN4442EN00EN_0002

Siemens

On the HG 3500 these parameters are set by using standard switch administration.

2.5 Bandwidth Requirements

The actual bandwidth per active payload connection depends on the selected encoding

algorithm and the specified sampling time.

2.5.1 Encoding

G.711, G.723 or G.729 encoding can be selected.

● G.711 encoding generates a net data rate of 64 Kbps,

● G.723 compresses to 6.4/5.3Kpbs and

● G.729 compresses to 8Kpbs (see Table 2-1 IP Overhead and BW per Connection for actual

data rates).

Wideband codecs according to G.722 are supported between optiPoint 410 IP phones. The

required bandwidth is the same as for G.711. Note that the gateway itself does not terminate

G.722 voice payload.

2.5.2 Sampling Time

Voice needs to be digitized before it can be assembled into IP packets.

Note

The TOS byte can be read in a number of different ways:

● Two 3-bit values for precedence and priority

● One 6-bit value as a combination of both 3-bit values (DiffServ CP)

● The entire TOS byte including two fill bits

For IPDA, the entire TOS byte is specified. The two least significant bits are always

set to zero.

See Section 8.1, “Key Words”.

Note that there is virtually no delay introduced in generating G.711 encoding from

TDM voice packets (Algorithmic Delay = 0 ms).