ZyXEL Communications P-202 Outgoing Packet Filtering Process, Filter Structure of the Prestige

Prestige 201 ISDN Access Router

Outgoing

Packet

Data Filtering

Match

No match

		Call Filtering
Built-in		No	User-defined		No
		match			match
default			Call Filters
Call Filters			(if applicable)
	Match			Match

Active Data

Initiate call if line not up

Send packet and reset Idle Timer

Drop packet

Drop packet				Drop packet
if line not up				if line not up
	Or				Or
			Send packet				Send packet
		but do not reset				but do not reset
			Idle Timer				Idle Timer

Figure 6-1 Outgoing Packet Filtering Process

For incoming packets, your Prestige applies data filters only. Packets are processed depending upon whether a match is found. The following sections describe how to configure filter sets.

The Filter Structure of the Prestige

A filter set consists of one or more filter rules. Usually, you would group related rules, e.g., all the rules for NetBIOS, into a single set and give it a descriptive name. The Prestige allows you to configure up to twelve filter sets with six rules in each set, for a total of 72 filter rules in the system.

You can apply up to four filter sets to a particular port to block multiple types of packets. With each filter set having up to six rules, you can have a maximum of 24 rules active for a single port. The following diagram illustrates the logic flow when executing a filter rule.

6-2 Filter Configuration