Cabletron Systems CSX400 - Manual (Page 35)

The Special Database Window 3-15
CSX Bridge View
The Special Database Window
Many Cabletron bridges incorporate a special database, which lets you create a
customized set of Þlters that the bridge uses in Þlter/forward decisions. You can
create, conÞgure, and enable Þlters in the special database. On receipt of a packet,
the CSX will Þrst read the packet and check it against special Þlters.
When it receives a packet, the bridge Þrst checks the special database. Looking at
each enabled Þlter, starting with the lowest numbered Þlter, the bridge compares
the following Þelds to the corresponding Þelds in the received packet:
¥ Destination address
¥ Source address
¥ Ethernet or Token Ring data type
¥ Up to 16 hex integers (64 bytes) of the data Þeld
In addition, a Þlter can also specify at which port or ports the packet must be
received for the Þlter to be applicable. If a received packet matches all the contents
of an enabled Þlter, the bridge forwards the packet to the deÞned set of ports: all,
some, or none.
Filters provide broad conÞguration ßexibility. For example, you can deÞne
multiple scenarios for a single Þlter by specifying different combinations of
receive port/destination port. You can use wildcard characters in Þlter Þelds to
force a match with particular bits of the received packetÕs destination address,
source address, or data. You can specify an offset for the data Þeld, to specify the
starting point in the data where the bridge looks for the match. For entries that
donÕt match any of the enabled Þlters, you can conÞgure the bridge to Þlter or
forward the entry or pass the Þlter/forward decision to the Filtering Database; see
The Filtering Database Window , page 3-20 .
To open the Special Database window:
1. Display the Device menu by clicking on the Front Panel button.
2. In the Device menu, drag down to Special Database and then right to
Ethernet and release (Token Ring will be grayed out).