IPmux-1/1E Installation and Operation Manual Chapter 4 Troubleshooting and Diagnostics
Frequently Asked Questions 4-29
of 2142, hence all the packets leaving the IPmux are tagged accordingly. This
unique value was assigned to RAD by the IANA organization for TDMoIP
applications.
The network elements may be used to give priority to the TDMoIP traffic
according to the UDP destination field.
Question: Does allocating a sufficient bandwidth ensure the proper functionality
of an IPmux-based application?
Answer
A sufficient bandwidth is not enough to ensure a steady environment for the
IPmux, since networks loaded with additional non-IPmux LAN traffic (e.g. PCs
traffic) or incompetent Ethernet/IP network may cause several problems:
• Jitter - The IPmux packets may suffer a delay variation (although all the traffic
will eventually pass through due to that fact that there is sufficient bandwidth).
Packets will be delayed for different periods of time due to overloaded
networks, queuing mechanisms, etc. IPmux can compensate for some jitter
(IPmux-1 up to 300 msec, IPmux-4/8/16 up to 32 msec for E1 and 24 msec for
T1) but bigger jitter will cause problems.
• Misordering - Packets might be sent in different order than the order in which
they were originally sent from the IPmux.
Note that a certain IPmux version which fixes misordering is available - please
contact Tech support.
• Packet Loss - Packets might be dropped/ignored by some elements in the
network (Routers/Switches) due to insufficient processing power to handle the
load, queuing mechanisms, buffer overflows, etc.
Normally these problems are solved by giving priority to the IPmux traffic over all
other traffic.
As can be shown, even though there is sufficient bandwidth, there might still be
cases in which the traffic will be transmitted from all the sources at the same time
and thus create a momentary load on the network element (Router/Switch), even
when this load that does not exceed the available bandwidth. Since the IPmux is
constantly transmitting, the TDMoIP traffic will always be a part of such a load.
When no priority is given to the TDMoIP traffic, the network elements will handle
the TDMoIP traffic as any other type of traffic.
All the above degrade the performance of the IPmux unit, although an adequate
amount of bandwidth is provided for the IPmux.
Please refer to FAQ 3338 to understand how to check the IPmux and network
performance and how to solve problems.