Netgear RT338 참조 가이드

Configuring Filters

9-1

This chapter describes how to use and configure filters for your Model RT338 ISDN Router.

The router uses filters to decide whether to allow passage of a data packet and/or to make a call 
over the ISDN line. Three types of filters are involved: incoming data filters, outgoing data filters, 
and call filters. Data filters screen the data to determine if the packet should be allowed to pass. 
Call filters are used to determine if a call should be placed.

Outgoing packets must pass through the data filters before they encounter call filters. 
The call filters are divided into two groups: default call filters and user-defined call filters. 
The Model RT338 router has default call filters that filter out administrative packets (for example, 
RIP packets). The router applies the default filters first and then, if applicable, applies the 
user-defined call filters as shown in 

.

For incoming packets, the router applies data filters only. Packets are processed depending on 
whether or not a match is made. The router lets you customize the filter sets that you want to use. 
The following sections describe how to configure the filter sets for the router.

7787EA

Outgoing

packet

Data

filters

Initiate call

if line not up

Send packet

and reset

idle timer

Send packet

 but do not

reset idle timer

Active data

Drop packet
if line not up

Or

No

match

Match

Match

Send packet

 but do not

reset idle timer

Drop packet
if line not up

Or

Match

No

match

No

match

Call filters

Drop

packet

Built-in

default call

filters

User-defined

call filters

(if applicable)