Nortel business policy switch 2000, User Manual

Page: 292 / 412

292 Chapter 4 Policy-enabled networks
208700-C
A filter or filter group is associated through a policy with interface groups. Packets
received from any port that is in an interface group are classified with the same
filters.
Each group of filters is associated with actions that are executed when the packet
matches the filters in the group. The filter group and the associated actions,
meters,
shaping criteria, and interface groups are referenced by a policy, which
dictates the overall traffic treatment.
Filters are associated with an interface group, action, metering, and shaping
criteria, through a policy. There are two levels of precedence that both work from
the lowest order 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
Note: Layer 2 and IP filters cannot coexist in the same group.
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 group.