280 Chapter4 Policy-enabled networks
208700-B
Each group of filters is associated with actions that are executed when the packet
matches the filters in the group. The filter grou p and the associated actions,
meters, and interface groups are referenced by a policy , which dictates the overall
traffic treatment.
Filters are associated with an interface group, action, and metering through a
policy. There are two levels of precedence t hat b oth wor k from the l owest ord er to
the highest:
order of filters in a filter group
order of policies
Layer 2 filters
There are 14 available layer 2 filters in the BPS 2000. The layer 2 filters are used
to classify traffic based on the following criteria:
Layer 2 information, including VLAN ID, IEEE 802.1p priority, and
etherType
Layer 3 information, including DSCP and IP protocol such as TCP/UDP
Layer 4 information, including TCP/UDP port ranges
Layer 2 classifiers can be associated with the following actions:
Drop matching packets.
Change DSCP of matching IP packets. If you request changing the DSCP for
non-IP traffic, the request will be ignored.
Note: Among policies, any policy with a Layer 2 filter group must have
a lower precedence (higher order) than any policy with an IP filter gr oup.
Note: If a layer 2 filter specifies layer 3 or layer 4 infor mation, that f ilter
must match IP traffic only.