Vidicode V-Tap VoIP Manual page 18

Tunnel Min Packet Size
Tunnel Packets are network packets sniffed by the V-Tap VoIP. These
are the wanted VoIP packets coming from your phone and local
network. After they passed the internal filters and match the
minimum size, they are sent with the Tunnel protocol to the server
or stored onto SD card.
The default minimum size of 60 bytes is also the minimum standard
Ethernet packet size. This means that packets of all sizes are taken.
There may be situations where it is handy to increase the size, to
minimize the overhead of stored packets. For example, when the size
is set to 61 all ACK-packets from the TCP protocol are discarded.
Tunnel TCP Port Filter
The TCP packets that are recorded (sniffed) from the local network
must pass this filter, else they are discarded.
The TCP Port Filter set to 0 (zero) disables the filter function. Then all
TCP packets are recorded, including all internet traffic, downloads
and streaming media. The receiving Tunnel server can still pick out
the VoIP calls, but on a busy local network this is not advised to do,
because the V-Tap VoIP probably gets overloaded.
Disabling the filter is therefore only useful when the V-Tap is
connected to one or more VoIP phones, not a trunk or network with
other data traffic.
To store the SIP protocol only, the port filter must be set to 5060.
The Unify HFA protocol uses port 4060. Cisco SCCP uses port 2000.
It is also possible to enter two ports; for example, "5060+2000".
Note: This port number is also used as a filter for UDP packets.
Tunnel UDP Port Filter
UDP packets, coming from the local network, can be filtered in the
same way as TCP packets. The SIP protocol uses most of the time UDP
with a random higher port number to transport the voice data, the
so called RTP stream.
With standard SIP on the local network, this filter can be set to 0
(zero) to allow the V-Tap unit to take all UDP packets.
When the RTP stream is known, it is possible to enter a range of
ports; for example, "40000-44000".
Note: All UDP packets that have a port number the same as the
entered "Tunnel TCP Port Filter" are also stored.
V-Tap VoIP Manual EN v2.7 Oct 2018 © 2017-2018 Vidicode 18