Nortel BCM50a, Configuration Manual

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BCM50a Integrated Router Configuration — Advanced
Chapter 11
Filter configuration
This chapter shows you how to create and apply filters.
Introduction to filters
Your BCM50a Integrated Router uses filters to decide whether to allow passage
of a data packet, make a call, or both. There are two types of filter applications:
data filtering and call filtering. Filters are subdivided into device and protocol
filters.
Data filtering screens the data to determine if the packet is allowed to pass. Data
filters are divided into incoming and outgoing filters, depending on the direction
of the packet relative to a port. Data filtering can be applied on either the WAN
side or the LAN side. Call filtering is used to determine if a packet is allowed to
trigger a call. Remote node call filtering is only applicable when using PPPoE
encapsulation.
Outgoing packets must undergo data filtering before they
encounter call filtering as shown in Figure 53 .