5.4. Network Queue QoS Policy Command Reference

This command creates a text description stored in the configuration file for a configuration context.

The no form of this command removes any description string from the context.

This command creates a context to configure a network queue policy. Network queue policies define the ingress and egress network queuing at the adapter card network node level.

Network queue policies define ingress and egress network queues similar to a service ingress QoS policy.

The no form of this command removes the network-queue policy from use. However, the network queue with policy-name default cannot be modified or deleted.

This command is used to modify the size of the packet that schedulers operate on. Modification only impacts schedulers and queue statistics. The actual packet size is not modified, nor can it be. Only the size used by the schedulers to determine the scheduling is changed. The packet-byte-offset command is meant to be a mechanism that can be used to compensate for downstream encapsulation or header removal. The scheduling rates are affected by the offset, as well as the statistics (accounting) associated with the queue. The packet-byte-offset command does not affect port-level and service-level statistics. It only affects the queue statistics. The network-queue policy applies in both the ingress and egress directions.

The add and subtract keywords are mutually exclusive. Either add, subtract, or none must be specified.

There are three modes of packet-byte-offset operation:

Packet byte offset configuration can be applied at the policy level, in which case it applies to all of the queues within the policy, or at the individual queue level so that it applies only to a specific queue.

The no version of this command enables legacy 7705 SAR behavior where the queue rates are relative to the packet size with the internal fabric header added, but without the FCS.

This command enables the context to configure a QoS network-queue policy queue. Network queues are created with default queue 1 (non-multipoint) and queue 9 (multipoint) automatically assigned.

The queue command with the multipoint keyword allows the creation of multipoint queues. Only multipoint queues can receive ingress packets that need flooding to multiple destinations. By separating the unicast traffic from multipoint traffic at network ingress and handling the traffic on separate multipoint queues, special handling of the multipoint traffic is possible. Each queue acts as an accounting and (optionally) shaping device, offering precise control over potentially expensive broadcast, multicast, and unknown unicast traffic. Only the back-end support of multipoint traffic (between the forwarding class and the queue based on forwarding type) needs to be defined. The individual classification rules used to place traffic into forwarding classes are not affected. Queues must be defined as multipoint at the time of creation within the policy.

The multipoint queues are for multipoint-destined service traffic. Within non-multipoint services, such as Epipe services, all traffic is considered unicast due to the nature of the service type. Multicast and broadcast-destined traffic in an Epipe service will not be mapped to a multipoint service queue.

The no form of this command removes the forwarding class-to-queue mapping, causing the forwarding class to use the default queue instead. When a queue is removed, any pending accounting information for each network queue created due to the definition of the queue in the policy is discarded.

The 7705 SAR does not support the avg-frame-overhead command. It is always set to 0 and cannot be modified.

This command defines the method used by the system to derive the operational CIR and PIR settings when the queue is provisioned in hardware. For the CIR and PIR parameters individually, the system attempts to find the best operational rate depending on the defined constraint.

The no form of the command removes any explicitly defined constraints used to derive the operational CIR and PIR created by the application of the policy. When a specific adaptation-rule is removed, the default constraints for rate and cir apply.

This command specifies the relative amount of reserved buffers for a specific ingress network adapter card forwarding class queue or egress network port forwarding class queue. The value is entered as a percentage. The resultant CBS size can be larger than the MBS. This will result in a portion of the CBS for the queue to be unused and therefore should be avoided.

The no form of this command returns the CBS size for the queue to the default for the forwarding class.

The high-prio-only command allows the reservation of queue buffers for use exclusively by in-profile packets as a default condition for access buffer queues for this network queue policy. For network queues, in-profile packets are high priority, and out-of-profile packets are low priority.

Note: When a low-priority RED/WRED slope is enabled on a queue, the high-prio-only setting is not used. When that slope is disabled, then the high-prio-setting is used.

Modifying the current MBS for the queue through the mbs command will cause the default high-prio-only function to be recalculated and applied to the queue.

The no form of this command restores the default value.

This command specifies the relative amount of the queue space for the maximum buffers for a specific ingress network adapter card forwarding class queue or egress network port forwarding class queue. The value is entered as a percentage.

The Maximum Burst Size (MBS) value is used by a queue to determine whether it has exhausted its total allowed buffers while enqueuing packets. Once the queue has exceeded its maximum amount of buffers, all packets are discarded until the queue transmits a packet. A queue that has not exceeded its MBS size is not guaranteed that a buffer will be available when needed or that the packet’s RED/WRED slope will not force the discard of the packet. Setting proper CBS parameters and controlling CBS oversubscription is one major safeguard to queue starvation (when a queue does not receive its fair share of buffers). Another is properly setting the RED/WRED slope parameters for the needs of the network queues.

The MBS size can sometimes be smaller than the CBS. This will result in a portion of the CBS for the queue to be unused and should be avoided.

The no form of this command returns the MBS size for the queue to the default for the forwarding class.

This command defines the administrative Peak Information Rate (PIR) and the administrative Committed Information Rate (CIR) parameters for the queue. Defining a PIR does not necessarily guarantee that the queue can transmit at the intended rate. The actual rate sustained by the queue can be limited by oversubscription factors or available egress bandwidth.

The CIR defines the percentage at which the system prioritizes the queue over other queues competing for the same bandwidth.

The rate command can be executed at any time, altering the PIR and CIR rates for all queues created through the association of the SAP ingress or SAP egress QoS policy with the queue-id.

The no form of the command returns all queues created with the queue-id by association with the QoS policy to the default PIR and CIR parameters (100, 0).

This command specifies the name of slope policy associated with the network queue.

This command configures the rate of traffic leaving the network.

With the include-fcs option, the egress rate limit is applied to the traffic rate egressing the port with the 4-byte Ethernet FCS field included. If this option is not configured, the egress rate limit is applied to the traffic rate egressing the port without the 4-byte Ethernet FCS field included, and the actual rate of packets leaving the port is slightly higher than the configured egress rate value.

The include-fcs option is not supported on the 8-port Ethernet Adapter card (version 2), 7705 SAR-A Fast Ethernet ports (ports 9 to 12), or 4-port SAR-H Fast Ethernet module. On the 6-port SAR-M Ethernet module, the include-fcs option is always on and cannot be disabled to compensate for the 4-byte FCS.

The allow-eth-bn-rate-changes option enables the Y.1731 ETH-BN client MEP option on the port. In applications such as a point-to-point microwave link, where degradation on the line can result in reduced link bandwidth, the egress rate can be dynamically changed based on the available bandwidth on the link as indicated by the ETH-BN server. When enabled, the received rate overrides the configured sub-rate for the port. For information on ETH-BN, including which Ethernet ports support this functionality, refer to the 7705 SAR OAM and Diagnostics Guide, “ITU-T Y.1731 Ethernet Bandwidth Notification (ETH-BN)”.

The bandwidth indicated by the ETH-BN server includes the FCS; therefore, the include-fcs option must be selected if the allow-eth-bn-rate-changes option is selected or the dynamically changed bandwidth will not match the intended rate.

The hold-time is used to limit the number of bandwidth changes as requested by the ETH-BN server. After a rate change occurs based on a Bandwidth Notification Message (BNM), any BMN received before the hold timer expires will be ignored.

The no form of this command returns the value to the default.

This command selects the network-side scheduling option for Ethernet ports on the equipment listed in Table 10 and Table 12.

On the 6-port Ethernet 10Gbps Adapter card and the 7705 SAR-X, scheduler-mode is permanently set to support 4-priority-hqos and is not user-configurable. There is no keyword to configure 4-priority-hqos.

With profiled (or rate-based) scheduling, both in-profile and out-of-profile scheduling are supported. Packets with a flow rate that is less than or equal to the CIR value of a queue are scheduled as in-profile. Packets with a flow rate that exceeds the CIR value but is less than the PIR value of a queue are scheduled as out-of-profile. In-profile traffic has strict priority over out-of-profile traffic.

Profiled scheduling does not take queue type into consideration. With queue type-based scheduling, queues are divided into two categories – those that are serviced by the Expedited scheduler and those that are serviced by the Best Effort scheduler. The Expedited scheduler has precedence over the Best Effort scheduler.

Four-priority scheduling combines both profiled and queue type-based scheduling. The combination provides four scheduling priorities. Packets are scheduled in the following order, in strict priority fashion:

Note: 16-priority is the default scheduling option on the 8-port Gigabit Ethernet Adapter card, 10-port 1GigE/1-port 10GigE X-Adapter card, 2-port 10GigE (Ethernet) Adapter card, 2-port 10GigE (Ethernet) module, Packet Microwave Adapter card, 6-port SAR-M Ethernet module, 7705 SAR-M, 7705 SAR-H, 7705 SAR-Hc, 7705 SAR-A, 7705 SAR-Ax, 7705 SAR-W, and 7705 SAR-Wx Ethernet ports. These cards and ports support 16-priority scheduling, but not profiled or 4-priority scheduling. In addition, 16-priority scheduling is not supported on the 8-port Ethernet card or 4-port SAR-H Fast Ethernet module. For information on 16-priority scheduling, refer to Network Egress Scheduling.

The fc is created with default unicast queue-id 1 and default multicast queue-id 9 automatically configured. The specified queues contain the PIR, CIR, CBS, and MBS configurations.

Use the multicast-queue and queue commands to change the fc queue-id assignments from their default queue assignments.

The no form of this command restores the default queue.

This command overrides the default multicast forwarding type queue mapping for fc fc-name. The specified queue-id must exist within the policy as a multipoint queue before the mapping can be made. Once the forwarding class mapping is executed, all multicast traffic at network ingress using this policy is forwarded using the queue-id. Use the queue queue-id multipoint command to create the specified queue-id.

The multicast forwarding type includes the unknown forwarding type and the broadcast forwarding type unless each is explicitly assigned to a different multipoint queue. When the unknown and broadcast forwarding types are left as default, they will track the defined queue for the multicast forwarding type.

The no form of the command sets the multicast forwarding type queue-id back to the default queue (queue 9).

This command enables the context to configure forwarding-class-to-queue mappings.

The no form of this command removes the queue-id from the network-queue policy and from any existing network ingress or network egress ports using the policy, and sets the queue-id back to the default queue (queue 1).