Chapter 4 Policy-enabled networks 281Using 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 ofthe matching IP traffic or the IEEE 802.1p for all types of traffic. If a layer 2 filteris installed on an untrusted port, then the associated action must change the DSCP(if matching IP traffic), IEEE 802.1p, and drop precedence of all matching traffic.If a layer 2 filter is installed on an unrestricted port, you can specify an action tochange or ignore either the DSCP (if matching IP traffic), IEEE 802.1p, and dropprecedence of the matching traffic.Refer to Table 57 for more information on layer 2 traffic, either IP or non-IP, andtrusted, 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 destinationand subnet addresses, DSCP, and IP protocols such as TCP/UDP• Layer 4 information, including TCP/UDP port numbers (port ranges are notsupported by layer 3 filters)IP filters have the same actions as layer 2 filters. If an IP filter is installed on atrusted port, then it cannot change the DSCP of the matching IP traffic or 802.1puser priority. If an IP filter is installed on an untrusted port, then it must change theDSCP, IEEE 802.1p, and drop precedence of the matching IP traffic. If an IP filteris installed on an unrestricted port, you configure that interface to change or noteither the DSCP, IEEE 802.1p, and drop precedence of the matching IP traffic, asyou want.Refer to Table 57 for more information on layer 2 traffic, either IP or non-IP, andtrusted, 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 byusing either IP or layer 2 filters. To change IEEE 802.1p priority and dropprecedence for non-IP traffic, you must use layer 2 filters.
