Filtering
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IP Router Pattern Filtering
Pattern filtering may be used on any portion of the IP frame. IP pattern filtering behaves the sa me as bridge pattern filtering,
except the start of the IP frame is offset 0, because the IP router function of the brid ge/router handles only the IP frame
itself.
IP pattern filtering may use any combin ation of filtering operators as described in the bridge pattern filters.

Protocol Discrimination

Protocol discrimination may be required to prevent or li mit the protocols within an IP frame that may travers e a routed Local
Area Network.
In Local Area Networks, there may be many different Transport layer protocols that coexist within the IP Network layer.
TCP, UDP, and ICMP are just a few of the common protocols in use today. Each of these protocols is encapsul ated within
an IP frame, and therefore is s ubject to the IP routing function. If you would like to discriminate against a particular protocol
to prevent its usage of the routed LAN facilities the P840 router provides programmable filter masks that may be defined to
act on any part of the IP frame.
The IP Router Filter Patterns menu is l ocated under the Filter Set-Up Menu. Within the IP Router Filter Patterns Men u there
exists a Help function that can be used as a reference during IP Router Filter Pattern creation. This Help function includes all
of the logical operators that may be a pplied to the mask expression.