6.1.1. Resource Allocation for Network QoS Policy

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.

Note: 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 vice versa.

For every FC in use, the system allocates two classification entries in hardware, if the FC is configured to use both the unicast meter and the multicast meter or if the default meter 9 is configured in the policy. If multiple match criteria entries map to the same FC, then each of these are allocated two classification entries in hardware. For example, if there are two match-criteria entries that map to FC ‘af’, then a total of four classification entries are allocated in hardware and if there are four match-criteria entries that map to FC ‘af’, then a total of 8 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 to be in use when it is associated with an FC in use.

For computing the number of QoS resources used by an access uplink port:

Only the FCs used by the match-criteria classification entries are to be considered for the 'number of FCs'. Therefore are referred to as ‘FC in use’. Also, note that in network policy of type 'ip-interface' default multipoint meter 9 is created in a policy, whereas, for policy of type 'port' 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 a 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, then the FC will use the unicast meter for all traffic types. In this case, the FC requires a single classification entry in hardware.

If a 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, then the FC will use the unicast meter for all traffic types. In this case, the FC requires a single classification entry in hardware.

If a 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 used, use the equation given below to arrive at 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 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.

Note: In the worst case, only 2 classification entries are used per FC in a network policy, as 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 is available.

Only those meters that are associated with FCs need to be considered for number of meters. Note, that only FCs in use are considered.

6.1.2. Basic Configuration

A basic network QoS policy must conform to the following:

6.1.3. Create a Network QoS Policy

Configuring and applying QoS policies other than the default policy is optional. A default network policy of the appropriate type is applied to each uplink port.

To create an network QoS policy, define the following:

Use the following syntax to create a network QoS policy.

The following commands associated a network QoS policy with the access-uplink port.

The following is a sample configuration output for uplink port 1/1/1 with network policy 600 applied to the interface.

6.1.4. Default Network Policy Values

The default network policy access uplink ports is identified as policy-id 1. Default policies cannot be modified or deleted. Table 29 lists default network policy parameters.

6.1.5. DSCP Marking for CPU-Generated Traffic

DSCP marking for CPU generated traffic is not configurable by the user. The default values are listed in Table 30.

Note: DSCP and Dot1P values in the table are applicable when remarking is disabled at port level.

6.1.6. Default DSCP Mapping Table

Table 31 lists default DSCP mapping values.

6.2.1. Deleting QoS Policies

A network policy is associated by default with access uplink ports.

You can replace the default policy with a non-default policy, but you cannot remove default policies from the configuration. When you remove a non-default policy, the policy association reverts to the appropriate default network policy.

6.2.2. Remove a Policy from the QoS Configuration

Use the following syntax to delete a network policy.

6.2.3. Copying and Overwriting Network Policies

You can copy an existing network policy to a new policy ID value or overwrite an existing policy ID. The overwrite option must be specified or an error occurs if the destination policy ID exists.

The following is a sample of the copied policies output.

6.2.4. Editing QoS Policies

You can change existing policies, except the default policies, and entries in the CLI. The changes are applied immediately to all access uplink ports where the policy is applied. To prevent configuration errors use the copy command to make a duplicate of the original policy to a work area, make the edits, and then overwrite the original policy.