Mitel MIVOICE OFFICE 250, Installation And Administration Manual

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MiVoice Office 250 Installation and Administration Guide
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assuming all jitter buffers are set to accommodate 40 ms maximum jitter level. For business
communication quality service, one-way delay (UDP traffic) should not exceed 120 ms, assuming
all jitter buffers are set to accommodate 80 ms maximum jitter level.
•
Network Jitter
: Variance in delay. For near toll quality service, average jitter should not exceed
20 ms and maximum jitter should not exceed 40 ms. For business communication quality service,
average jitter should not exceed 40 ms and maximum jitter should not exceed 80 ms.
•
Hops
: The number of router points a data packet must pass through during transmission. Hops
should not exceed 15 in order to minimize the number of potential problem points.
•
Committed Information Rate (CIR) and Burst Rate (BR)
: 512 Kbps/each. This criterion means that
512 Kbps will always be available, and the link may achieve a BR of up to 1024 Kbps for short
periods if the bandwidth is available from the WAN provider. Typically, there is no guarantee of
BR availability. Voice traffic should stay below the CIR value. When voice traffic exceeds the
CIR value, packets may begin to queue within the Frame Relay network and become subject to
delay. These packets could eventually be tagged as Discard Eligible (DE). Packets marked as
DE could be discarded before reaching their destination. The potential queuing delay and packet
loss can adversely affect voice quality.
Mitel also recommends the following PSTN performance characteristics:
•
Loop Current
: 18–20 mA
•
Line Voltage
: 42.5–56.5 V
•
Ring Voltage
: 55–130 Vrms (Class A)
•
db Level
: Must pass at least +3dBm without distortion into a 600-ohm load
All of the preceding PSTN requirements are consistent with the EIA/TIA-464B specifications. Use
Ethernet switching mechanisms rather than Ethernet hubs. Switches offer inherent Ethernet
advantages over hub (shared) technology. Switches provide advantages such as segmentation,
full-duplex operations, Layer 2 prioritization, etc.
For any router that will have VoIP traffic passing through it, program the router to prioritize the packets
sent by the IP devices. In addition, program the external router to fragment large data packets into
smaller packets. This reduces the possibility that voice packets will have to wait for a large data
packet at the router.
Automatic NAT Detection
Network Address Translation (NAT) is a method for translating internal IP addresses or network
addresses into public Internet addresses.
The Automatic Network Address Translation (NAT) Detection feature allows 52xx/53xx phones to
operate inside or outside a private network NAT or firewall without having to change the IP Settings\
NAT Address Type field every time the phone is relocated. The feature enables Mitel hard IP phones
and the Mitel 8602 IP softphone to place and receive calls either from inside or outside a Mitel private
network.
IMPORTANT
Using background music and paging on a hard IP phone, such as the IP PhonePlus,
consumes as much bandwidth as a telephone call to the device. If the site has limited
bandwidth, make sure IP phone users do not enable background music and that they
limit using the paging feature.