Media5 Mediatrix 4104, Reference Manual, Page: 88 / 466

Chapter 4 - Web Interface – SIP Parameters SIP Interop
66 Mediatrix 4104
Now, let’s assume endpoint “B” comes back to life and the Mediatrix 4104 tries again to contact it before UDP
and TCP are released from the penalty box. First, the unit tries UDP, but it is currently in the penalty box and
there is another transport left to try. The Mediatrix 4104 skips over UDP and tries the next target, which is TCP.
Again, TCP is still in the penalty box, but this time, it is the last target the Mediatrix 4104 can try, so penalty
box or not, TCP is used all the same to try to contact endpoint “B”.
There is a problem if endpoint “B” only supports UDP (RFC 2543-based implementation). Endpoint “B” is up,
but the Mediatrix 4104 still cannot contact it: with UDP and TCP in the penalty box, the unit only tries to contact
endpoint “B” via its last choice, which is TCP.
The same scenario would not have any problem if the penalty box feature was disabled. Another option is to
disable TCP in the Mediatrix 4104, which makes UDP the only possible choice for the unit and forces to use
UDP even if it is in the penalty box.
You must fully understand the above problem before configuring this feature. Mixing endpoints that do not
support the same set of transports with this feature enabled can lead to the above problems, so it is suggested
to either properly configure SRV records for the hosts that can be reached or be sure that all hosts on the
network support the same transport set before enabling this feature.
Penalty Box Configuration
The following steps describe how to configure the penalty box feature.

To set the SIP penalty box parameters:
1. In the web interface, click the SIP link, then the Interop sub-link.
Figure 31: SIP – Interop Web Page
2. In the Penalty Box section, enable the SIP penalty box feature by selecting Enable in the Penalty
Box Activation choices.
The penalty box is always “active”. This means that even if the feature is disabled, IP addresses are
marked as invalid, but they are still tried. This has the advantage that when the feature is enabled,
IP addresses that were already marked as invalid are instantly put into the penalty box.
3. Set the amount of time, in seconds, that a host spends in the penalty box in the Penalty Box Time
field.
Changing the value does not affect IP addresses that are already in the penalty box. It only affects
new entries in the penalty box.
4. Click Submit if you do not need to set other parameters.
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