
Networking 97
IP Telephony Configuration Guide
Each site supports four VoIP ports. Assume the codex is G.729 Annex B, 20 ms payload.
Assuming full-duplex links, peak bandwidths per call are from Table 12 on page 95 which is
between 24.8 kbit/s and 27.6 kbit/s peak transmission or approximately 28 kbit/s.
Route R1-R2 needs to support 4 VoIP Calls. R4-R5 needs to support eight VoIP calls. The
incremental peak bandwidth for VoIP traffic is therefore:
With BCM VoIP gateway bandwidth requirements and
Traceroute
measurements, the R4-R5
link is expected to support the Santa Clara/Richardson, Santa Clara/Tokyo and the Ottawa/Tokyo
traffic flows. The other IP telephony traffic flows do not route over R4-R5. A peak of eight calls
can be made over R4-R5 for the four IP telephony ports per site. R4-R5 needs to support the
incremental bandwidth of 8 x 12 = 96 kbit/s.
To complete this exercise, the traffic flow from every site pair needs to be summed to calculate the
load on each route and loaded to the link.
Figure 47 Calculating network load with IP telephony traffic
R1-R2 peak VoIP Load 4 28 kbit/s()112kbit/s==
R4-R5 peak VoIP Load 8 28 kbit/s()112kbit/s==
Business Communications
Manager IP telephony
Router
Santa Clara/Richardson traffic
Ottawa/Tokyo traffic
Richardson
Santa Clara
Tokyo
Ottawa
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