7.4 Configuring the FoIP Service (Based on the H.248
Protocol)
This topic describes how to configure the FoIP service when the H.248 protocol is used to
transmit the fax data service over the IP network.
Prerequisites
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The communication between the MG and the MGC must be in the normal state, and the
fax mode on the MGC side must be consistent with the fax mode on the MG side.
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The voice service port used by the FoIP service and the voice service on that port must be
in the normal state.
Context
The FoIP service can be classified according to the following modes:
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According to the coding/decoding mode: In this mode, the FoIP service is classified into
T.30 transparent transmission fax (using the G.711 coding) and T.38 fax (using the T.38
coding).
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According to the role of the MGC: In this mode, the FoIP service is classified into the
SoftSwitch-controlled fax and the self-switch fax (the fax flow is controlled by the MGC
itself).
The MA5616 supports the self-switch mode and the auto-negotiation mode:
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Self-switch: If the self-switch mode is configured, the fax working mode of the MA5616
is not controlled by the MGC. Therefore, manual configuration is required.
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Auto-negotiation: If the auto-negotiation mode is configured, the fax working mode of the
MA5616 is automatically configured during the negotiation with the MGC. Therefore,
manual configuration is not required.
The MA5616 supports the V2 and V3 fax flows.
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In the V2 negotiation flow, the MG determines the transmission mode to be used
(transparent transmission mode or T.38-based transmission mode), and determines whether
the fax port ID is increased by 2. No signaling negotiation is performed when the port ID
is increased by 2. Therefore, when the V2 T.38 is configured, the IDs of the local and peer
ports must be configured consistently. That is, the port IDs are both increased by 2 or neither
of the port IDs is increased by 2.
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In the V3 negotiation flow, the softswitch determines the transmission mode to be used
(transparent transmission mode or T.38-based transmission mode). To be specific, if the
softswitch requires the T.38-based transmission mode, this transmission mode is used;
otherwise, the transparent transmission mode is used. In addition, the softswitch determines
whether the fax port ID is increased by 2 through signaling negotiation.
The MA5616 supports the 10 ms packing function and the RFC 2198 function.
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10 ms packing function: In addition to the 20 ms G.711 transparent transmission, the fax
transparent transmission function is added with the 10 ms G.711 transparent transmission.
This reduces delay, improves the performance of transparent transmission, and decreases
the impact of packet loss on the transmission of the fax service data.
SmartAX MA5616 Multi-service Access Module
Configuration Guide
7 Configuring the Voice Service
Issue 04 (2011-10-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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