Specifications

VoiceFinder VoIP Gateway Configuration Guide (APOS 2.0) Release Version 3.1
AddPac Technology Co., LTD
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Another disadvantage to be considered is delay. There are 2 kinds of delay essentially in
telephone or VoIP network. They are Propagation Delay and Handling Delay. Propagation delay
is a kind of delay due a medium such as copper or fiber optic used in a network. The delay in
delivery is so small, so human’s ears can not feel, but when this delay is accumulated, it drops
the voice quality as a result. A type of delay which can be managed by an administrator is
Handling Delay. This delay can be divided by the delay, which take a place, in encoding and
decoding process of the codec and the delay, which takes a place in the packet processing of the
gateway. VoIP Gateway determines a path for the entered voice packet and it is configured to do
the task of moving to the output part. You should consider the status of the network and QoS
support of the equipment for Encoding/ Decoding process delay when you select a type of
codec. The following Table 3.2 presents the delays in processing time for each codec.
Compression Format Bit Speed(Kbps) Compression
Delays (ms)
MOS Scores
G.711PCM 64 0.75 4.1
G.729 CS-ACELP 8 10 3.92
G.729a CS-ACELP 8 10 3.7
G.723.1 MP-MLQ 6.3 30 3.9
G.723.1 ACELP 5.3 30 3.65
Table 3.2 Delays in Code for each Compression Formats
3.1.3. Dial Peer
One of the things that you must understand for VoIP installation and configuration is Dial Peer.
A dial peer, also know as an addressable call endpoint, is a device that can originate or receive a
call in a telephone network. The dial peer is used to set the characteristics contributed to a call
leg in all the voice technologies, in which a telephone call can be executed. As it is shown in
Figure 3.1 and Figure 3.2, the call leg a section in where the voice call connected between the
2 points. There are 4 call legs presented between the call originating telephone and ending
telephone. The 2 call legs in Figure 3.1 are shown in a view point of source gateway and
Figure 3.2 shows the call legs in a view point of destination gateway. An operator or
administrator of voice network divides the call originating point and destination, then apply a
specific optional function to the call leg. These optional functions to be applied to the call leg