Mitel MiVOICE BUSINESS, Инструкция по инженерии

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Network Configuration Specifics
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• Transmission of data and voice over an RF link presents potential security issues that
system administrators and users should be aware of. For example, it is recommended that
encryption be enabled.
• Electro-Magnetic Interference generated by wireless phones and PCs might need to be
considered in sensitive environments such as health care facilities, research laboratories
and some industrial sites since this interference could affect the operation of critical equip-
ment in the facility.
• Likewise, Electro-Magnetic Susceptibility needs to be considered since reception on the
wireless phones may be affected by other RF devices, such as microwave ovens and certain
portable phones. A site survey is strongly recommended.
• In a DECT WLAN, the only time that the RTP voice stream is carried by RF is when both
DECT handsets are registered with the same primary FRP. If the DECT handsets are
registered with different FRPs then the RTP voice stream will be routed out of the VLAN
onto the LAN and then back onto the WLAN.
When calculating bandwidth requirements, the voice traffic carried on the LAN between
DECT phones that are registered with different FRPs should be considered.
FAX AND MODEM CONNECTIONS OVER IP USING G.711 PASS
THROUGH
The 3300 ICP supports the transmission of Fax over IP (FoIP) via G.711 pass through, and
also Fax over IP and SIP via the ITU T.38 recommendation.
G.711 FAX PASS THROUGH OVERVIEW
The ICP controllers can transmit Fax information over an IP trunk from one controller to another
as G.711 packets. In effect, the data modulated signals are passed as voice across the IP
network. For this reason, compression cannot be used on these signals. Fax machines are
sensitive to time delays and error rates. Typically, these devices are designed to run over TDM
links. A lost IP packet can contain a significant quantity of data. Although the Fax application
can recover from some losses, it may not be able to handle large losses such as a burst loss
of IP packets.
Within the PSTN, echo cancellers will be disabled if tone detectors within the PSTN detect a
FAX or MODEM calling tone (2100 Hz).
The controllers, however, do not currently support this functionality. As a result, if a FAX machine
is connected directly to an ONS or LS port on the ICP so that the data can be transported to
another ICP via IP trunk forwarding, the ICP will not disable the internal echo canceller. The
presence of an echo canceller will impede the ability of the FAX to establish a full duplex
connection, resulting in a slower half duplex connection being established.
G.711 FAX PASS THROUGH PERFORMANCE GUIDELINES
Due to the many variables involved in sending Fax data over G.711 pass-through on IP trunks,
there is no guarantee of reliable transport. However, practical experience has shown that, with
some careful network considerations, such a link can be made to work. These considerations
include: