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Chapter4 Policy-enabled networks 281
Using the Business Policy Switch 2000 Version 1.2
•Change IEEE 802.1p and drop precedence of matching packets.
If a layer 2 filter is installed on a trusted port, then it cannot change the DSCP of
the matching IP traffic or the IEEE 802.1p for all types of traffic. If a layer 2 filter
is installed on an untrusted port, then the associated action must cha nge the DSCP
(if matching IP traffic), IEEE 802.1p, and drop precedence of a ll ma tc hin g t ra ffic.
If a layer 2 filter is installed on an unrestricted port, you can specify an action to
change or ignore either the DSCP (if matching IP traffic), IEEE 802.1p, and drop
precedence of the matching traffic.
Refer to Table 5 7 for more information on layer 2 traffic, either IP or non-IP, and
trusted, untrusted, or unrestricted ports.
IP filtersIP filters are used to classify IP traffic based on the following criteria:
•Layer 3 information, including IP source and subnet addresses, IP destinati on
and subnet addresses, DSCP, and IP protocols such as TCP/UDP
•Layer 4 information, including TCP/UDP port numbers (port ranges are not
supported by layer 3 filters)
IP filters have the same actions as layer 2 filters. If an IP filter is installed on a
trusted port, then it cannot change the DSCP of the matching IP traffic or 802.1p
user priority. If an IP filter is i nstalled on an untrust ed port , then i t must change the
DSCP, IEEE 802.1p, and drop precedence of the ma tching IP tr af fic . If a n IP fi lter
is installed on an unrestricted port, you configure that interface to change or not
either the DSCP, IEEE 802.1p, and drop precedence of the matching IP traffic, as
you want.
Refer to Table 5 7 for more information on layer 2 traffic, either IP or non-IP, and
trusted, untrusted, or unrestricted ports.
Changing IEEE 802.1p priority and drop precedenceYou can change the IEEE 802.1p priority and drop precedence for IP traffic by
using either IP or layer 2 filters. To change IEEE 802.1p priority and drop
precedence for non-IP traffic, you must use layer 2 filters.