This section provides examples for calculating the amount of resources needed for a service ingress policy when using IP DSCP table-based classification with CAM-based policing. For calculations when CAM-based classification is used, see Examples: calculating resources required for CAM-based classification.
The examples in this section use the two equations below to calculate the value for num-qos-classifiers used in the sap-ingress QoS policy. See Computation of resources used per SAP ingress policy for CAM-based classification for details on these equations.
total number of classification entries (TC)
where:
E(i) is equal to 1 if FC(i) is in use by the dscp-classification policy. Otherwise, E(i) is equal to 0.
C(i) is the number of classification entries that are required by FCi to identify different traffic types. For a given FC, for each traffic type (unicast, broadcast, multicast, and unknown-unicast) configured to use a meter, a classification entry is needed.
The default FC requires one or more additional resources even if all the eight FCs are configured in the dot1p or IP DSCP classification policy, as shown in the example in section Example 1: Epipe, IES, and VPRN services using unicast traffic type.
total number of QoS resources required (TQ)
where:
TP is the number of meters/policers used
In addition, the examples show how to determine the number of classification entries for each forwarding class. For example, FCh2 (shown below) is the sum of four traffic types: (unicast (U), broadcast (B), multicast (M), and unknown-unicast (U-u)). See Calculating the number of classification entries per FC for more information.
If BUM entries are not explicit and multipoint traffic is expected, meter "11" is used and the "M" traffic type is given a "1".
Consider the following items when calculating the resources required when using IP DSCP table-based classification:
The meters used per FC for different traffic types is in accordance with the rules given in Service ingress meter selection rules and the number of classification entries per FC is provided in Determining the number of classification entries. In addition:
If an FC uses one meter for all four traffic types, then the maximum of four classification entries are needed.
As a minimum, an FC uses a single meter.
Users are provided an option to use between one and four meters per FC, one meter each for four different traffic types, in a VPLS service.
Users are provided an option to use either one and two meters per FC, one meter each for two traffic types, in IES and VPRN service when using multicast.
Users can use only a single meter per FC, for unicast traffic, in Epipe, IES, and VPRN service, where IES and VPRN are not configured to use multicast.
For an Epipe, VPLS, IES, or VPRN SAP, the FCs in use can be determined by counting the FCs configured in the DSCP classification policy and the default FC configured in the SAP ingress policy.
For routed VPLS (RVPLS), to determine the FCs in use, use the following:
For SAPs on access port, the FCs in use is the sum total of all FCs configured across the following four items:
the DSCP classification policy associated as an override policy under the IP interface context
the port DSCP classification policy associated with the access port
the untagged-fc value configured under the access port
the default-fc configured in the SAP ingress policy
For SAPs on hybrid ports, the FCs in use is the sum total of all FCs configured across the following three items:
the DSCP classification policy associated as an override policy under the IP interface context
the network port policy associated with the hybrid port
the default FC value configured under the SAP ingress policy