10. QoS Shapers and Shaper QoS Policies
This chapter provides information to configure shaper QoS policies using the command line interface.
Topics in this chapter include:
10.1. Overview of QoS Shapers and Shaper QoS Policies
Shapers are used to control access or network traffic flows through the 7705 SAR.
QoS shapers refer to per-SAP and per-VLAN dual-rate aggregate shapers that operate at the QoS tier 2 level.
Shaper QoS policies refer to policies that contain shaper groups, such as per-customer (MSS) dual-rate aggregate shapers that operate at the QoS tier 3 level.
Configuring a dual-rate aggregate shaper means setting PIR and CIR values. For per-customer (MSS) aggregate shapers, this is done through a shaper group.
Dual-rate aggregate shapers are applied to shaped and unshaped SAP traffic for access ingress and access egress flows, and to shaped and unshaped VLAN traffic for network egress flows.
On a hybrid port, where access and network traffic can share the same physical port, a shaper policy can be applied independently to access egress or network egress traffic.
For more information on QoS shapers and shaper QoS policies, see the following sections:
10.2. Basic Configuration
This section contains the following topics related to creating and applying shaper QoS policies:
A basic shaper QoS policy must conform to the following rules.
- Each shaper policy must have a unique policy identifier (name).
- Default values can be modified but parameters cannot be deleted.
10.2.1. Creating a Shaper QoS Policy and Shaper Groups
Configuring and applying shaper QoS policies is optional. If no shaper QoS policy is explicitly defined, the default shaper QoS policy (“default”) is applied.
To create a new shaper policy, define the following:
- a shaper policy name — the system does not dynamically assign a name
- a description (optional) — a brief description of the policy
- a shaper group (optional) and its PIR and CIR values — a shaper group is a dual-rate aggregate shaper that is used mainly as a per-customer (MSS) aggregate shaper
- an unshaped SAP shaper group (optional) — the shaper group used by the group of all unshaped SAPs for the purpose of traffic arbitration with the shaped SAPs on a port
Use the following CLI syntax to configure a shaper policy and shaper groups within the shaper policy:
The following output shows the configuration for “shaper_policy_2”:
10.2.2. Applying a Shaper QoS Policy and Shaper Groups
A shaper QoS policy must be assigned to an Ethernet MDA for access ingress per-customer aggregate shaping, or to a port for access egress per-customer aggregate shaping. Once a shaper policy is assigned, a shaper group can be applied.
Shaper groups are created within the shaper policy and provide the per-customer (MSS) aggregate shapers. The unshaped SAP shaper group within the policy provides the shaper rate for all the unshaped SAPs (4-priority scheduled SAPs). For each shaped SAP, an ingress or egress shaper group can be specified.
For ingress, the shaper group assigned to a SAP or unshaped shaper group must be a shaper group from the shaper policy assigned to the Ethernet MDA.
For egress, the shaper group assigned to a SAP or unshaped shaper group must be a shaper group from the shaper policy assigned to the port.
All ingress shaped or unshaped SAPs configured with the same ingress shaper group on an Ethernet MDA have their aggregate traffic shaped at the shaper group rate. Similarly, all the egress shaped or unshaped SAPs configured with the same egress shaper group on a port have their aggregate traffic shaped at the shaper group rate.
On all 7705 SAR fixed platforms (with the exception of the 7705 SAR-X), when a shaper policy is assigned to an Ethernet MDA for access ingress aggregate shaping, it is automatically assigned to all the Ethernet MDAs in that chassis. The shaper group members contained in the shaper policy span all the Ethernet MDAs. SAPs on different Ethernet MDAs configured with the same ingress shaper group will share the shaper group rate.
For hybrid ports, one shaper policy can be applied to the network egress traffic as well as to the access egress traffic. For network egress, all the shaped interfaces (VLANs) and unshaped interfaces are bound to the default shaper group contained in the shaper policy assigned to the network egress port. The access egress traffic is bound to the shaper group assigned to each shaped SAP or to the default shaper group if none is assigned, and all the unshaped SAPs are assigned to the unshaped shaper group or to the default shaper group if none is assigned. Traffic is then scheduled between the network and access shaper groups by ensuring that the CIR rate for each shaper group is scheduled before any of the excess information rate (EIR) traffic from any of the shaper groups.
 | Note: On the 8-port Ethernet Adapter card, shaped and unshaped VLANs are arbitrated towards the port but egress-rate cannot be enabled. |
10.2.2.1. Applying a Shaper Policy
The following examples illustrate the CLI syntax to apply a shaper policy to an MDA and a hybrid port (access and network egress).
The following outputs show an ingress shaper policy applied to an MDA and different shaper policies applied to access egress and network egress traffic on a hybrid port:
10.2.2.2. Applying a Shaper Group
Shaper groups are applied to SAPs on Epipe, Ipipe, and VPLS services, and to interface SAPs on IES and VPRN services. The shaper group must exist within the shaper policy assigned to an MDA.
When an unshaped-sap-shaper-group is configured within a shaper policy, it is automatically applied to the unshaped SAPs on the MDA. Operators do not need to specifically apply the unshaped SAP shaper group.
Use the following CLI syntax to apply a shaper group to a VPLS SAP. The syntax is similar for Epipe and Ipipe SAPs. The syntax is also similar for IES and VPRN services, except that the SAP is configured on a service interface.
The following output shows shaper group “sg1” applied to access ingress traffic on a VPLS SAP:
10.2.2.3. Viewing Shaper Policy Information
Use the show>qos>shaper-policy command to view information on a shaper policy, its shaper groups (including the unshaped SAP shaper group), the PIR and CIR values, and where the policy is used.
10.2.3. Default Shaper QoS Policy Values
The default shaper policies are identified by the policy name “default”. The default policies cannot be deleted. Table 65 displays the default shaper policy parameters.
Table 65: Shaper Policy Defaults
Field | Default |
description | “Default Shaper QoS policy.” |
shaper-group | “default” |
description | “Default Shaper Group.” |
pir-rate | max |
cir-rate | 0 |
The following output displays the default configuration:
10.2.4. Configuring per-SAP Aggregate Shapers and an Unshaped SAP Aggregate Shaper (H-QoS)
Configuring tier 2 per-SAP aggregate shapers applies to Gen-2 SAPs configured with 16-priority scheduling mode and Gen-3 SAPs. Access ingress and access egress shapers are configured under the same CLI context.
Configuring a single tier 2 aggregate shaper for all unshaped SAPs applies to Gen-2 SAPs configured with 4-priority scheduling mode. Access ingress and access egress shapers are configured under different CLI contexts.
10.2.4.1. Creating 16-Priority Shaped SAPs and Configuring per-SAP Aggregate Shapers
Create shaped Gen-2 SAPs by configuring the scheduler mode to 16-priority. On Gen-3 hardware, the scheduler mode is always 4-priority and SAPs are shaped.
Configure a shaped SAPs’ aggregate rates by setting the CIR and PIR, as required. The SAP must be shut down before the scheduler mode and the agg-rate and cir-rate can be changed.
Use the first CLI syntax (below) to create shaped SAPs for access egress and access ingress for VLL and VPLS services (including routed VPLS), and the second syntax for IES and VPRN services. Examples are given for Epipe and IES services on Gen-2 and Gen-3 hardware:
In the examples below, MDA 1/12 is a Gen-2 adapter card and MDA 1/3 is a Gen-3 adapter card.
The following outputs display the shaped SAP configuration for Epipe and IES services:
10.2.4.2. Configuring an Unshaped Aggregate CIR for All 4-Priority Unshaped SAPs (Access Ingress)
Use the first CLI syntax to set the unshaped-sap-cir for all unshaped 4-priority SAPs on a 7705 SAR-8 Shelf V2 or 7705 SAR-18. The fabric profile must be in aggregate mode before an unshaped SAP aggregate CIR can be assigned. Use the second CLI syntax for a 7705 SAR-M, 7705 SAR-H, 7705 SAR-Hc, 7705 SAR-A, 7705 SAR-Ax, 7705 SAR-W, or 7705 SAR-Wx; it does not apply to the 7705 SAR-X.
The following output displays the fabric profile configuration for an H-QoS configuration:
For the 7705 SAR-M, 7705 SAR-H, 7705 SAR-Hc, 7705 SAR-A, 7705 SAR-Ax, 7705 SAR-W, and 7705 SAR-Wx:
10.2.4.3. Configuring an Unshaped Aggregate CIR for All 4-Priority Unshaped SAPs (Access Egress)
To provide arbitration between the bulk (aggregate) of unshaped SAPs and the shaped SAPs, assign a rate to the unshaped SAPs. Refer to the 7705 SAR Interface Configuration Guide for command descriptions.
Use the following CLI syntax to configure a per-port CIR rate limit for the aggregate of all 4-priority unshaped SAPs on the egress port:
The following output displays the port configuration for the unshaped SAPs in an H-QoS configuration:
10.2.5. Configuring per-VLAN Shapers and an Unshaped VLAN Shaper
This section contains information on the following topics:
10.2.5.1. Configuring Per-VLAN Network Egress Shapers
Per-VLAN network egress shapers can be configured for network interfaces.
The queue-policy command is used to enable and disable the network egress per-VLAN shapers on a per-interface basis. If the no queue-policy command is used, the VLAN (that is, the interface) defaults to unshaped mode. The agg-rate-limit command cannot be accessed unless a network queue policy is assigned to the interface.
Use the following CLI syntax to configure a per-VLAN network egress shaper on a network interface. Refer to the 7705 SAR Router Configuration Guide for command descriptions.
10.2.5.2. Configuring a CIR for Network Egress Unshaped VLANs
To provide arbitration between the bulk (aggregate) of unshaped VLANs and the shaped VLANs, assign a rate to the unshaped VLANs.
Use the following CLI syntax to configure a CIR for the bulk of network egress unshaped VLANs. Refer to the 7705 SAR Interface Configuration Guide for command descriptions.
10.3. Service Management Tasks
This section describes the following service management tasks:
10.3.1. Removing and Deleting QoS Policies
A QoS policy cannot be deleted until its associations with all the ports are removed.
Since one shaper policy can be assigned to multiple ports, you must remove all the associations to the ports before deleting the shaper policy.
Use the following CLI syntax to remove a shaper policy from a port and then delete the shaper policy from the QoS configuration:
10.3.2. Copying and Overwriting QoS Policies
You can copy an existing shaper policy to a new shaper policy or overwrite an existing shaper policy. If the destination policy ID exists, the overwrite option must be specified or an error occurs.
Use the following syntax to overwrite an existing shaper QoS policy.
The following output displays the copied policies:
10.3.3. Editing QoS Policies
You can change existing policies and entries in the CLI. The changes are applied immediately to all queues where this policy is applied. To prevent configuration errors, copy the policy to a work area, make the edits, and then write over the original policy.