V-Tap ISDN BRI Manual EN v2.6 Dec 2018 © 2017-2018 Vidicode 15
Once a connection has been established between the V-Tap and the
receiving Tunnel server, the chosen port number is kept active for
the duration of the communication session. When connection is lost
for some reason, a new source port is chosen for the next
connection. This ensures fast reconnection, because the TCP protocol
does not allow the same source port to be used again within a short
time. After an OS specific timeout of normally a few minutes, the
port numbers become available again for reuse.
Tunnel Connect Timeout
This timeout is used when the V-Tap tries to connect to the Tunnel
server. The default 22 seconds is enough to send 4 requests. If no
reply comes from the remote side within this time, the V-Tap starts
trying again after a few seconds with a new source port number.
Storage onto SD card just continues and is not interrupted by any
connection or disconnection of the Tunnel.
Tunnel Idle Timeout
This timeout is used to disconnect the active tunnel to the server,
only when no data must be sent anymore. Default, the idle-timeout
is disabled and the tunnel stays connected forever.
The timeout is added for (yet) unknown situations where it is not
allowed to have an open TCP connection for a long time.
Tunnel Data Encryption
The data inside the Tunnel protocol is sent encrypted over the
network. The used method is AES with a 256-bit Cryptographic Key.
For privacy reasons it is advised to leave the encryption enabled.
Encryption Password
This parameter is used for the encryption of the Tunnel data and the
file on SD card (see below). The receiving side of the Tunnel data, the
Apresa or CR-VoIP software, must use the same password. Leaving
the password empty is still doing the encryption but is less secure.
The single and double quotation marks (‘ and “)
cannot be used !
