Cabletron Systems CSX400 - Manual (Page 37)

The Special Database Window 3-17
CSX Bridge View
Receive Port List Box
The receive ports available on the bridge are listed here. This box allows you to
select the port at which a packet must be received in order for the Þlter in question
to be applied. Selecting ÒAllÓ will allow the Þlter to be applied to packets at any
receive port.
Destination Ports List Box
Use this box to select one or more ports to which any packets matching Þlter
parameters will be forwarded.
Filter Number
Each Þlter has a unique identifying number. The rest of the information in the
window describes the Þlter identiÞed by the displayed number. When the bridge
uses the Special Database to make a forwarding decision, it starts with the lowest
numbered enabled Þlter.
Filter State
Each Þlter in the Special Database can be enabled or disabled individually.
Offset
The Offset deÞnes the starting point of a 64 byte window in a received frameÕs
data Þeld that is examined for a match to a Þlter entry. Offset Т0У means that the
comparison begins at the Þrst bit after the packetÕs header Þeld.
Destination Address
The bridge compares the Destination Address entered in this Þeld to the
Destination Address of a received frame. An ÒXÓ in any position serves as a
wildcard, forcing a match for that position.
Source Address
The bridge compares the Source Address entered in this Þeld to the Source
Address of a received frame. An ÒXÓ in any position serves as a wildcard, forcing
a match for that position.
Type
The Type Þeld (also known as the Length Þeld) identiÞes the packet type (Novell,
AppleTalk, and so forth). The bridge compares this Type to the Type Þeld of a
received frame. An ÒXÓ in any position serves as a wildcard, forcing a match for
that position.
Data
The four lines of Data in the Special Database window show the values that the
Þlter compares to a 64 bit window of the data Þeld of a received frame, beginning
at the Offset. An ÒXÓ in any position serves as a wildcard, forcing a match for that
position.