This section describes the allocation of QoS resources for network QoS policies. When the port mode is changed to access-uplink, a default network QoS policy is applied. For the default policy, two meters and eighteen classification entries in hardware are allocated.
The number of resources used per network QoS policy determines the number of access-uplink ports that can be configured. If more resources are used, fewer access-uplink ports can be used, and the other way around.
For every FC in use, the system allocates two classification entries in hardware, provided the FC is configured to use both the unicast meter and the multicast meter, or provided the default meter 9 is configured in the policy. If multiple match criteria entries map to the same FC, each of these are allocated two classification entries in hardware. For example, if there are two match-criteria entries that map to FC ‟af” a total of four classification entries are allocated in hardware, and if there are four match-criteria entries that map to FC ‟af” a total of eight classification entries are allocated in hardware.
For every meter or policer in use, the system allocates one meter in hardware. A meter or policer is considered in use when it is associated with an FC in use.
To calculate the number of QoS resources used by an access-uplink port, determine the following items:
number of match-criteria entries used to identify the FC
number of FCs to use
Only the FCs used by the match-criteria classification entries are considered for the ‟number of FCs” and are therefore are referred to as ‟FCs in use”. Also, in network policies of the type ip-interface, the default multipoint meter 9 is created in a policy; whereas, for policy of type ‟port”, the default multipoint meter needs to be explicitly configured by the user, if required.
Use the following rules to compute the number of classification entries per FC in use:
If an FC is in use and is created without explicit meters, use default meter 1 for unicast traffic and default meter 9 (if configured) for all other traffic types (that is, broadcast, multicast, and unknown-unicast). This requires two classification entries in hardware. If default multipoint meter 9 is not configured, the FC uses the unicast meter for all traffic types. In this case, the FC requires a single classification entry in hardware.
If an FC is in use and is created with an explicit unicast meter, use that meter for unicast traffic and use default meter 9 (if configured) for all other traffic types. This requires two classification entries in hardware. If default multipoint meter 9 is not configured, the FC uses the unicast meter for all traffic types. In this case, the FC requires a single classification entry in hardware.
If an FC is in use and is created with an explicit unicast meter and explicit multicast meter, use the unicast meter for unicast traffic and multicast meter for all other kinds of traffic. This requires two classification entries in hardware.
Given the number of match criteria and the number of FCs in use, use the following equation to calculate the total number of classification entries per policy (for example TC):
where:
E(i) is the number of match- criteria entries that classify packets to FCi. For 7210 SAS platforms, the maximum number of classification entries per policy can be 64 (including default).
2 is the number of classification entries that are required by FCi.
In the worst case, only 2 classification entries are used per FC in a network policy, because only two traffic types are supported.
Determine number of policers or meters to use (for example TP). A maximum of 16 meters per network policy are available.
Only those meters that are associated with FCs need to be considered for number of meters; only FCs in use are considered.