Enterasys Networks ENTERASYS ATX manual Adding a New Filter

Using ATX Port Filtering

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CAUTION

Remember that the ATX’s performance may be adversely affected if you define a large number of Port filters. Because the ATX has to decode packet data further than it would if no filters were established, the forwarding rate of traffic may be slowed as packets are buffered and decoded.

Typically, if you create Bridge Address Table filters or only a small number of Port filters, the forwarding rate of the ATX will not be affected; however, the more complex or greater number of Port filters that you create, the more traffic flow will be affected. For this reason, it is good practice to delete filters from the Port Filtering Table when they are no longer needed.

NOTE

If you are also performing Work Group Configuration on your ATX, remember that each Work Group that you establish will reduce the number of Port filters you can configure at a one-to-one ratio.

Adding a New Filter

The ATX allows you to create up to 100 Port filters (total for all connected ports). To add a new filter to the ATX or modify a previously configured Port Filter:

1.In the Port field, type in the interface number of the port to which this filter will apply.

2.Click on the Type button to select the filter type: ENTRY (the default type) EXIT, MENTRY, or MEXIT.

•Entry filters are used to screen incoming traffic at a receive port. They are applied to packets as they are being received by a specified port.

•Exit filters are used to screen outgoing traffic from the receive port. They are applied to packets after they are received and forwarded by a specified port.

•Mirror Entry filters are used to screen incoming traffic at a receive port that supports and is using port mirroring. They are applied to packets as they are being received by a specified port.

•Mirror Exit filters are used to screen outgoing traffic from the receive port when the port supports and is using port mirroring. They are applied to packets after they are received and forwarded by a specified port.

3.Click on the Pseudo button to indicate whether you want to create a pseudo filter.

•YES indicates that you wish to create a pseudo filter — one which gathers statistics on all packets that have met the filtering criteria, but does not actually filter them. Pseudo filters are useful if you want to determine the effects of a filter without actually implementing it, or for monitoring traffic

Editing the Port Filters Table 4-5