Download RAD Data comm Vmux-210 Specifications

Chapter 6 Troubleshooting and Diagnostics
Installation and Operation Manual
In order to overcome this situation, the Vmux-210 uses the fragmentation
feature. The fragmentation function enables the Vmux-210 to halt the
transmission of a long, lower priority packet, and begin the transmission of a
higher priority packet without waiting to finish the transmission of the lowerpriority packet. The transmission of the lower priority packet is then resumed
automatically after the transmission of the higher priority packet is
completed. In essence, fragmentation allows the Vmux-210 to "chop" long
packets in order to give higher priority to voice packets.
The size of the fragment packets is user-selectable.
Q: What is the end-to-end processing delay contributed by the Vmux-210 when
working with different compression algorithms (Coders)?
A: The end-to-end processing delay contributed by the Vmux-210 is as follows:
G723.1A (5.3/6.4 kbps) - 120-150 msec (depending on packet interval)
G729.A/8 kbps - 70 msec
G711.A/64 kbps - 45 msec
Please note that when used in an IP network, the Vmux-210 uses jitter
buffers in order to compensate for packet delay variation. The jitter buffers
are implemented in the Vmux-210 DSPs (Digital Signal Processors), and they
are adaptive to the packet delay variation. Each timeslot has its own jitter
buffer.
The size of the Vmux-210 jitter buffers is not user-configurable (with the
exception of jitter buffers for transparent timeslots). The jitter buffer size is
changed according to the packet delay variation, which is detected by the
DSP. Each voice packet that is sent out of the DSP includes a time stamp. The
DSP analyzes the time stamps on the received packets and controls the size
of the jitter buffer according to the delay between the received packets. The
delay variation tolerance is from 10 msec up to 300 msec.
Example: When using G.723.1 compression, the DSP expects to receive a
packet every 30 msec. If the delay between the received packets is higher
than 30 msec, the DSP will increase the size of the jitter buffer so that data
will not be lost.
Q: What files can be transferred to/from Vmux-210?
A: See the following table.
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Frequently Asked Questions
Vmux-210 Ver. 1.1