User`s guide

3-38
Configuring
3.11.3 Mirrored Filters
The ATX also allows you (via the existing port filtering feature;
(Chapter 5 in the ATX LAN Switch User’s Guide) to establish
“mirror filters” which can help reduce the amount of traffic seen by
the diagnostic port. Using a “mirror filter,” you can restrict the
amount of monitored traffic by filtering inbound or outbound
packets according to source and destination addresses, packet
types, frame protocols and offsets within the data field.
In port filters, there are currently two types you can select from:
Entry and Exit. With the addition of port mirroring, there are now
four types: Entry, Exit, PMEntry and PMExit. PMEntry applies to
any packet entering the port and PMExit is any packet leaving the
port. See Configuration Examples for implementation. The rest of
the parameters for setting up filters are identical, independent of
what the type is.
There are two major differences between mirror filter and packet
filter:
• A mirrored filter has the exact opposite affect as a port filter.
Mirrored filters will pass the traffic matching the filter rather
than being blocked as in packet filtering.
• Both inbound packets to the ATX and outbound packets
generated by the ATX are subject to the mirror filtering.
3.11.4 Example #1: LOCAL Port Mirroring
Port 1 is the diagnostic port where the analyzer resides.
Ports 2 and 3 are the
mirrored ports
mirror 2-3 to 1
discard
or
mirror 2-3 to 1
truncate
ATX LAN Switch
P1
P2 P3