Cabletron Systems CSX400 - Manual (Page 40)

CSX Bridge View
3-20 The Filtering Database Window
In Figure 3-8 , Filter Number 3 shows the Destination Ports as B54180E0, which
represents ports 1, 3, 4, 6, 8, 10, 16, 17, 25, 26, 27. HereÕs how to translate the hex
string to port numbers:
1. Translate each hex integer into a four-digit binary value:
B 5 4 1 8 0 E 0
1011 0101 0100 0001 1000 0000 1110 0000
Each “1” in the binary bitmask represents a Destination Port number:
B 5 4 1 8 0 E 0
1011 0101 0100 0001 1000 0000 1110 0000
1,X,3,4 X,6,X,8 X,10,X,X X,X,X,1617,X,X,X X,X,X,X, 25,26,27,X X,X,X,X
Deleting Special Database Filters
To delete an enabled Special Database Þlter:
1. In the Special Filters IO Table, select a filter to delete by clicking mouse
button 1 on the table entry.
2. Click mouse button 1 on the Delete button at the bottom of the window.
The Filtering Database Window
In Transparent bridging, each bridge port uses the deviceÕs Filtering Database to
determine a packetÕs route through the bridge. The Filtering Database is created
from permanent entries made via management, and from entries learned as the
bridge collects and stores the source address and port association from each
packet it receives.
When in the Forwarding state, the bridge examines each received packet and
compares the destination address to the contents of the Filtering Database. If the
destination address is located on the network from which the packet was
received, the bridge Þlters (does not forward) the packet. If the destination
address is located on a different network, the bridge forwards the packet to the
appropriate network. If the destination address isnÕt found in the Filtering
Database, the bridge forwards the packet to all networks. To keep Filtering
Database entries current, older entries are purged after a period of time, which is
called the Dynamic Aging Time.
The Filtering Database has two types of entries: Forwarding and Static. The
Forwarding view of the Filtering Database contain addresses that the bridge
NOTE
Deleting a Þlter doesnÕt ÒdeleteÓ the Þlter; it just clears all the entries you made for that
instance of the Þlter. In the example shown above, if you deleted the last entry in the list
(Filter Number 19, Receive Port 4, Destination Port 1) any other entries for Filter 19
would remain intact.