Overview of QoS policies on 7210 SAS-Mxp in network mode

QoS policies are applied on service ingress, access port egress, network port ingress and egress, and network IP interfaces ingress when configured to operate in network mode.

These policies allow users to configure the following:

classification rules for how traffic is mapped to FCs
FC association with meters and meter parameters used for policing (rate-limiting)
queuing parameters for shaping
QoS marking/interpretation

Several types of QoS policies exist:

service ingress policies for access SAP ingress

Service ingress QoS policies are applied to customer-facing SAPs. Traffic that enters through the SAP is classified to map to an FC. FCs are associated with meters or policers on ingress. Mapping traffic meters can be based on combinations of customer QoS marking (IEEE 802.1p bits), IP criteria, and MAC criteria. The policy defines the number of FC meters for unicast traffic and other meter characteristics (such as CIR, PIR, and so on). Each FC can be associated with different unicast parameters.

A service ingress QoS policy also defines up to three meters per FC for multipoint traffic for use with multipoint services. The system supports the configuration of up to 32 meters per service ingress QoS policy. In the case of VPLS, four forwarding types (not to be confused with forward classes) are supported: unicast, multicast, broadcast, and unknown. Multicast, broadcast, and unknown types are flooded to all destinations within the service, while the unicast forwarding type is handled in a point-to-point fashion within the service.
service egress policies for access SAP egress

Service egress QoS policies are applied to SAPs and map FCs to service egress queues for a service. The system allocates a maximum of eight queues per SAP for the eight FCs; this is not user configurable. All traffic types (unicast and BUM) share the same service egress queue. A service egress QoS policy defines the FC queue characteristics and how the FC to priority bits in the packet header are remarked (for example, IEEE 802.1p bits in the Ethernet VLAN tag) in the customer traffic.

On the 7210 SAS-Mxp, the user has a per-node or per-chassis option of configuring the SAP-based or access port-based egress queuing mode. The SAP-based egress queuing mode (port-scheduler-mode command disabled) uses a service egress QoS policy with the capability to use eight egress queues per SAP. The access port-based egress queuing mode (port-scheduler-mode command enabled) uses an access egress policy with the capability to use eight egress queues for all SAPs configured on the access port.

A service egress QoS policy or access egress policy also defines how to remark the FC-to-IEEE 802.1p bits in the customer traffic.
access egress policies for access port egress

An access egress policy is applied to all SAPs on the physical port (and not the logical port (SAP)) for SAP-egress policies. It applies to all the SAPs on the port. Access egress policies provide different capabilities based on the egress queuing mode applied to the node. In SAP-based egress queuing mode, an access egress policy defines the remarking of the FC-to-packet header bits. For example, IEEE 802.1p bits in the Layer 2 VLAN header.

In port-based egress queuing mode, the access egress policy, in addition to remarking, is used to define the queuing and scheduling behavior for the port-based egress queues. Access egress QoS policies are applied to ports and map forwarding classes (FCs) to port egress queues. The system allocates a maximum of eight queues per port for the eight FCs. The allocation is not user-configurable. All traffic types, (unicast and BUM traffic types) share the same queue on port egress.

An access egress QoS policy defines the FC queue characteristics and the remarking of the FC to priority bits in the packet header (for example, IEEE 802.1p bits in the Ethernet VLAN tag) in the customer traffic.
access ingress policies for access port ingress

An access ingress policy is applied to the physical port instead of the SAP; the policy applies to all SAPs configured on the specific access port. At ingress, the access ingress QoS policy uses dot1p, DEI with dot1p, or IP DSCP values to assign an FC and profile to traffic, which facilitates the classification of traffic received on the access port. The FC is associated with meters at ingress. An access ingress QoS policy allows the user to define up to one meter per FC for unicast traffic, and up to one meter per FC for multipoint traffic (broadcast, multicast, and unknown-unicast) for multipoint services. The system supports up to 16 meters per access ingress QoS policy.

Note:
This policy is available only when the node is operating in sap-scale mode high. See the 7210 SAS-Mxp, S, Sx, T Services Guide and 7210 SAS-Mxp, R6, R12, S, Sx, T Basic System Configuration Guide for more information about the sap-scale-mode command.
network policies for network and hybrid port, ingress and egress

For devices configured to operate in network mode, two types of network QoS policies are supported: one that is applied to a network IP interface and the other to a network port. Network QoS policies are applied to IP interfaces. On ingress, the policy applied to an IP interface maps incoming MPLS LSP EXP values to FC and profile state for traffic received from the core network. On egress, the network policy maps FC and profile state to MPLS LSP EXP values for traffic transmitted into the core network. The network policy applied to a network port maps incoming IP packets, DSCP, or dot1p values to the FC and the profile state for the traffic received from the core network. On egress, the network policy maps FC and profile state to DSCP or dot1p values for IP traffic transmitted into the core network.
network queue policies for network and hybrid port, egress

Network queue policies are applied on egress to network ports when operating in network mode. The policies define the FC queue characteristics for these entities. The FCs are mapped to the queues. The FC-to-queue mapping is static and not configurable. The number of queues is not user-configurable and the software allocates eight queues at the port level.
port scheduler policies for access port, network port and hybrid port egress

Port scheduler policies are applied on egress for access, network, and hybrid ports. These policies allow the user to define queue scheduling attributes, such as strict-priority queuing and weighted queuing.
slope policies

Slope policies are applied to the egress queues on the access, network, and hybrid ports. These policies define the WRED congestion management attributes, such as drop probability and thresholds for high-profile and low-profile traffic.
remark policies for access port, network port and hybrid port egress marking

Remark policies are applied to access ports/SAPs, network ports/IP interfaces, and hybrid ports/SAPs/IP interfaces to configure the marking values for different forwarding classes and profiles.These policies enable marking of packet header QoS fields for packets that are forwarded out of the port, SAP, or IP interface. See Remark policies for more information.
queue management policies for buffer allocation and slope configuration on service egress and network port egress

Queue management policies are applied to service egress, access port egress, network port egress, and hybrid port egress to configure CBS and MBS parameters for the egress queues and the WRED slope parameters for the queues.

The 7210 SAS-Mxp provides an option to use port-based queuing on access ports. This is a per-node configuration option and is mutually exclusive to the use of SAP-based egress queues (configured through service egress policies). When enabled, all SAPs on the access port share a set of 8 (eight) queues configured on the port and the access egress policy is used to define the queue parameters for port-based queues.

Service ingress, service egress, access egress, and network QoS policies are defined with a scope of either template or exclusive. Template policies can be applied to multiple entities (such as SAPs and ports); exclusive policies can only be applied to a single entity.

The following policies are supported:

one service ingress QoS policy and one service egress QoS policy applied to a specific SAP
one access egress QoS policy applied to an access port
one network QoS policy applied to a specific IP interface or network port, based on the type of network QoS policy; a network QoS policy defines both ingress and egress behavior
one network queue policy applied to the network port

If no QoS policy is explicitly applied to a SAP, port, or interface, a default QoS policy is applied.

The 7210 SAS-Mxp can operate in either the low SAP scale mode or high SAP scale mode. In low SAP scale mode, SAP and service scaling is limited by the amount of CAM resources available for the SAP-ingress policy (both classification and meters). In the high SAP scale mode, SAP and service scaling is significantly higher compared to the low SAP scale mode and use table-based classification with ingress service meters. The use of network port policies remains unchanged when the system is operating in the high SAP scale mode.

SAPs configured on ports operating in hybrid mode cannot be configured to use access ingress QoS policies. Therefore, the access-ingress-qos port-mode option is not supported for ports configured in hybrid mode.

The following QoS policies are supported on access ports and SAPs in the low SAP scale mode:

service ingress policy for SAP ingress classification and metering using the following:
- CAM-based classification and metering/policing
- table-based classification and CAM-based metering/policing
- table-based classification and service-meter pool, also called table-based meter/policer pool, for metering/policing
service egress policy for SAP egress queuing, shaping, and scheduling with an egress policy for marking only
access egress policy for access port egress queuing, shaping, scheduling, and marking (this policy is mutually exclusive with the use of service egress policies)

The following QoS policies are supported on access ports and SAPs in the high SAP scale mode:

service ingress policy for SAP ingress classification metering using the following:
- Epipe and VPLS SAPs using ingress table-based classification and policing on service delivery ports for higher SAP scaling
- IES and VPRN SAPs using table-based classification or CAM-based classification
- RVPLS SAPs using CAM-based classification and policing
access egress policy for port egress queuing, shaping, scheduling, and marking (this policy is mutually exclusive with the use of service egress policies)

A summary of the major functions performed by the QoS policies is listed in the following table.

Note:

Not all policies are supported on all platforms. See the following sections and chapters for more information.

Table: QoS policy types and descriptions for 7210 SAS-Mxp devices in network mode
Policy type	Applied at…	Description	Section
Service Ingress	SAP ingress	defines up to 32 FC meters and meter parameters for traffic classification defines match criteria to map flows to the meters based on any one of the criteria (optionally) can map the priority bits (IP DSCP (for all IP packets) and dot1p bits for tagged non-IP packets) to FC and profile for table-based classification (optionally) can use meters either from the CAM-based meter pool or the table-based service-meter pool	Service ingress QoS policies
Service Egress	SAP Egress	defines up to 8 FC queues maps FCs to the queues defines Queue parameters (for example, rate, priority, weight, and so on) for the queue that determine how the queue gets the available bandwidth and prioritized by the scheduler defines FC to remarking values	Service egress QoS policies on 7210 SAS-Mxp, 7210 SAS-R6, and 7210 SAS-R12
Access Ingress	Access Port	defines dot1p and IP DSCP classification criteria to use defines up to 16 meters per access ingress QoS policy	Access ingress QoS policies
Access Egress	Access Port	defines FC to remarking values when port-based queuing is enabled, it is used to configure the queue parameters for port-based queues	Access egress QoS policies on 7210 SAS-Mxp
Network (of type’ip-interface’)	IP interface	used for classification/marking of MPLS packets at ingress, defines MPLS LSP-EXP to FC mapping and 16 meters used by FCs at egress, defines FC to MPLS LSP-EXP marking	Network QoS policies in network mode
Network (of type’port’)	Network Ports and Hybrid Ports	used for classification/marking of IP packets at ingress, defines DSCP or dot1p to FC mapping and 16 meters at egress, defines FC to DSCP or dot1p marking or both	Network queue policies in network mode
Network Queue	Network Ports and Hybrid Ports	defines FC mappings to network queues and queue characteristics for the queues	Network queue policies in network mode
Slope	Access ports, Network ports and Hybrid ports	enables or disables the high-slope, low-slope, and non-TCP parameters within the egress pool	Slope policy parameters
Remark	Network Port, Access ports and Hybrid Ports	applied at egress, defines the FC to Priority Bits (DSCP or dot1p or EXP) marking	Remark policies on 7210 SAS-Mxp, 7210 SAS-R6, 7210 SAS-R12, 7210 SAS-S 1/10GE, 7210 SAS-Sx 10/100GE, and 7210 SAS-T (network mode)