Enterasys Networks CSX5500, CSX6000 Bridge Filters Background Information, Filter Destination MAC

CONFIGURING ADVANCED BRIDGING

Bridge Filters

BRIDGE FILTERS BACKGROUND INFORMATION

User-defined bridge filters allow you to filter unwanted traffic out of the network. The following table lists the four different types of bridge filters and the maximum number of filters that can be configured for each type:

Filter Type	Maximum
	Number of Each
source MAC address	50
filter
destination MAC	50
address filter
protocol filter	40
packet data filter	60
hardware filter	63

(in manual mode)

Note: If the mode of operation is changed, any previously defined filters will be deleted. Any previously defined protocol definitions will remain unchanged.

MAC address filters reference either the source or destination MAC address fields in a packet. Protocol filters use the protocol Id field in a packet. Packet data filters reference data outside the address and protocol fields in a packet. Each filter has a distribution list that identifies the potential destinations for a filtered packet.

For each filter category, there are three filtering actions that the system can perform on a packet: discard, forward, or connect.

PROTOCOL DEFINITIONS

If you configure any protocol filters, you must first configure any needed protocol definitions. After you define a protocol filter, it will automatically be assigned a protocol Id. The protocol Id is a required field when configuring a protocol filter.

You can define up to 10 protocol definitions. These definitions represent the protocol Id tokens for the protocol filter commands to use. Users specify the protocol name, and also the protocol Id value for the Ethernet type field and/or the 802.3 LSAP field.

Inspecting the 13th and 14th bytes of the MAC frame determines the packet format. These bytes are the length field in an 802.3 format frame, and are the Ethernet type field in an Ethernet format frame. If the value of the byte is less than hexadecimal 600, the packet is 802.3 format and the LSAP field is used for the protocol Id. If the value is greater than or equal to hexadecimal 600, the packet is Ethernet format and the Ethernet type field is used for the protocol Id.

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