V-Tap VoIP Manual EN v2.7 Oct 2018 © 2017-2018 Vidicode 28
3.3.11
Special network settings
EtherType Filter IP + ARP only
This hardware filter is very fast and looks at two bytes in all Ethernet
packets, called the EtherType. When active, only two protocols are
let through, namely Internet Protocol version 4 (IPv4) and the
Address Resolution Protocol (ARP). Both are always needed for
normal operation. All other protocols from the Internet Layer are not
needed when recording VoIP calls only.
More filtering can be done with the Tunnel filters, described above.
Max Data Length in Packets
This sets the maximum length of the data portion inside all
communicated packets on the network for Tunnel, FTP and Web.
The length excludes the Ethernet, IP and TCP headers, which are 54
bytes together. The maximum length of any packet on the network
can be 1514 bytes, so that leaves max 1460 bytes for the data part.
The default length is based on optimal performance when sending
data from an SD card.
There is probably no need to ever change this parameter when the
Tunnel is sending on a normal LAN. When sending directly on a WAN
or very busy LAN, the length might be decreased for better
performance (like 512).
LAN Service Timer
The default value is for normal network speed. When a lot of V-Tap
units are sending to the same Tunnel server, it might be better to
lower the speed to prevent an overload of streams.
The values 65 and 1 can be used for slow and slower sending.
The values 18 and 50 can be used for fast and faster sending.
MAC Configuration bits
This parameter holds important configuration bits for the network
interface and is further not explained in this manual. Do not alter
any of these bits without consulting the manufacturer.
The default value 0 is the same as C354, in which case the Ethernet
multicast packets are being filtered for the Tunnel function. To
enable the reception of multicast packets, set the value to C344.