1.1.1 Filter Overview

The following figure shows the functional blocks for filters on the Switch.

Figure 1-2: Function blocks of filters of the Switch

The following table provides an overview of the functional blocks shown in the figure.

Table 1-1: Overview of filter function blocks

Section and functional blocks		Overview of authentication VLAN functionality
Flow control section	Flow detection	This block detects a flow (specific frames) that matches a condition, such as MAC address, protocol type, IP address, TCP/UDP port number, or ICMP header.
	Forwarding and discarding	These blocks forward and discard frames found by the flow detection block.

To use a filter on a Switch, you need to create a filter entry that defines a combination of flow detection condition (such as MAC address, protocol type, IP address, TCP/UDP port number, or ICMP header) and an operation (forward or discard).

The following describes how a filter works on the Switch:

1. The filter entries set for each interface are searched in the order of priority specified by the user.

2. The search terminates when the filter entry matching the frame is found.

3. Whether the frame is forwarded or discarded is determined according to the operation specified for the filter entry.

4. If the frame does not match any filter entry, the frame is discarded. For details on the discard operation, see 1.1.7 Implicit discard.

Notes

If a frame is discarded on the receiving-side interface, the sending-side interface does not perform flow detection.

No filter can be used on the stack port.