Programmable Filtering

2From the CONFIGURATION MENU, enter an 8.

This will place you at the FILTER SET-UP MENU, where access to the individual filtering menus is obtained.

3From the FILTER SET-UP MENU, enter a 1.

This will place you at the MAC ADDRESS FILTERS MENU, where access to the MAC Address filters is obtained.

4From the MAC ADDRESS FILTERS MENU, make sure that the Filter Operation is currently set to “negative.”

This will cause the MAC Address Filters specified to be used for forwarding frames with the specified MAC addresses.

5At this menu, enter a 1.

This will place you at the first EDIT MAC ADDRESS FILTER MENU screen. At the prompt enter the MAC address for which you want to specify the filter.

6Enter the 12-digit Ethernet address of the Personal Computer system in the following format: 010203040506 (enter a Return)

The edit screen will fill in the information that the table knows about this address. For this example, let us assume that it knows that the address status is [not present] and is of [unknown] location.

In this example, the bridge/router is not aware of this station yet. The station has probably not been active for the bridge/router to “learn” any information about it.

Therefore, you will have to tell the bridge/router a little bit more about the station.

7Enter a 2 to enter the location of the station.

8The bridge/router will prompt you for the LAN that the station is located on; enter the name of this bridge/router’s LAN (LAN456789 for example).

Note that the Status of the address is marked as [present], the location is updated to LAN456789 and the Permanent entry is [enabled].

9Enter a 3 to [enable] the “Forward if Source” parameter. The edit screen will be updated to show the new information.

At this point, the address is added to the permanent filter table of the local LAN. This entry, therefore, will not be subject to the aging timer, and will remain active until it is removed from the permanent entry table.

When a frame of information is seen on the local LAN that contains the address of the Personal Computer in the source field of the frame, the bridge/router will forward it. All other frames seen on the local LAN that are destined for the remote LAN will be filtered.

Most programmable filtering options may be used for security purposes. The examples above are specific instances where the two “Forward if” functions may be used. Filter masks are presented in subsequent pages of this section.

B.6 — IOLINK-PRO & 520 Reference Manual