Specifications

Engineering Guidelines
224
Figure 37: IP trunk limit example
Table 66: IP networking limit calculations
Calculation Formula Result
Traffic from IP sets Number of sets (250) x 6 CCS 1500 CCS
Percentage networked Total traffic x 15% 225 CCS
Percentage traffic intercom Networked traffic x 35% 79 CCS
Percentage traffic trunk to PSTN Networked traffic – intercom traffic 146 CCS
Total Number of IP trunk channels
needed
ErlangB on total IP trunk traffic (225
CCS)
13 channels (P.01)
Number of channels needed for PSTN
trunks (G.711)
ErlangB on PSTN trunk traffic (146
CCS)
10 channels (see note)
(P.01)
Number of channels needed for
intercom/internal traffic (G.729a)
ErlangB on Intercom traffic (79 CCS) 7 channels (see note) (P.01)
Bandwidth needed
(use worst case)
Number of G.711 channels (10) x 100k
+ [Total number of channels (13) –
PSTN trunk channels(10)] x 40k
1120 kbps
WAN bandwidth required Assume with QoS so / 70% 1600 kbps
Number of channels (IP trunk) for IP
networking
Total number of channels 13 Channels