Configuring Call Capacity For A Line Interface - Linksys SPA9000 Administration Manual

Configuring Phone Lines and Calling Routing Behavior

Configuring Call Capacity for a Line Interface

Each line interface has a limited number of simultaneous calls that are allowed, based on the
Call Capacity parameter. When the maximum call capacity is reached, the SPA9000 does not
allocate any more calls to that line interface.
This section includes the following topics:
• "Bandwidth Requirements and Call Capacity, " on page 51
• "Setting the Call Capacity Parameter, " on page 52
Bandwidth Requirements and Call Capacity
The available connection bandwidth determines the maximum number of simultaneous calls
that the system can support with the appropriate audio quality. Before installing and
configuring the LVS components, use this information to determine the maximum number of
simultaneous VoIP connections that the system can support. For asymmetric connections, such
as ADSL, the maximum number of calls is determined by the upstream bandwidth. In general it
is a good practice to use no more than 75% of the total available bandwidth for calls. This
provides space for data traffic and helps ensure good voice quality.
Table 4-1 provides the approximate bandwidth budget for different codecs.
Each side of
Codec
conversation
G.711 110
G.726-40 87
G.726-32 79
G.726-24 71
G.726-16 63
G.729 55
Linksys Voice System Administration Guide
Configuring Line Interfaces on the SPA9000
Table 4-1 Bandwidth Budget
Approximate bandwidth budget (kbps)
2 calls 4 calls
220 440
174 348
158 316
142 284
126 252
110 220
6 calls 8 calls
660 880
522 696
474 632
426 568
378 504
330 440
51