RAD Data comm IPmux-11 - Manual (Page 122)

Chapter 6 Troubleshooting and Diagnostics Installation and Operation Manual
6-24 Frequently Asked Questions IPmux-11 Ver. 2.00
A configuration example:
Setting IP precedence of 101 and IP ToS of 1000 will give us the byte
10110000, which means that the IPmux IP ToS parameter should be
configured to 176 decimals.
UDP Destination Port
The IPmux uses the UDP protocol (Layer 4) in order to transfer the TDMoIP
traffic.
In the UDP protocol, the ¿Destination port¿ field is always set to the decimal
value 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.
Q : Does allocating a sufficient bandwidth ensure the proper functionality of an
IPmux-based application?
A : 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. PC
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, IPmux-11 up to 300 msec, IPmux-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.
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.
Refer to FAQ 3338 to understand how to check the IPmux and network
performance and how to solve problems.