CoS Three-Level Hierarchical Scheduling on MPLS Pseudowire Subscriber Interfaces

In three-level hierarchical scheduling, the CoS scheduler nodes at level 1, level 2, and level 3 form a scheduling hierarchy. You can configure many different three-level scheduling hierarchies, depending on the location of the interface set and the use of underlying interfaces. In all variations, the physical interface on which the logical tunnel resides is a level 1 CoS scheduler node and the queues reside at level 4. Three-level scheduling hierarchies can have up to eight class of service queues. Table 1summarizes the most common three-level hierarchical scheduling configurations and shows the interface hierarchy and CoS scheduler nodes.

Table 1: Three-Level Hierarchical Scheduling–Interface Hierarchy Versus CoS Scheduling Node Levels
Level 1	Level 2	Level 3	Level 4
Physical interface	Pseudowire interface set	Pseudowire service logical interfaces	One or more queues
Physical interface	Pseudowire transport logical interface	Pseudowire interface set	One or more queues
Physical interface	Pseudowire transport logical interface	Pseudowire service logical interfaces	One or more queues

Three-Level Scheduling Hierarchy: Pseudowire Logical Interfaces over a Transport Logical Interface

Figure 1 shows an MPLS pseudowire three-level scheduling hierarchy that includes two pseudowire service logical interfaces over a pseudowire transport logical interface. This variation uses the following scheduler nodes:

Level 4—Forwarding class-based queues
Level 3—Pseudowire service logical interfaces (ps0.1 and ps0.2) for subscriber sessions
Level 2—Pseudowire transport logical interface (ps0.0)
Level 1—Common/shared physical interface of the logical tunnel anchor point

You apply the traffic-control profiles at the pseudowire transport logical interfaces (level 2) and the pseudowire service logical interfaces (level 3).

Figure 1: Three-Level Scheduling Hierarchy Case 1: Pseudowire Service Logical Interfaces over a Transport Logical Interface Network architecture diagram with four layers: L1-Logical Tunnel Physical Interface, L2-Transport layer ps0.0 interface, L3-Resource layer ps0.1 and ps0.2 interfaces, L4-Queues for traffic management.

Network architecture diagram with four layers: L1-Logical Tunnel Physical Interface, L2-Transport layer ps0.0 interface, L3-Resource layer ps0.1 and ps0.2 interfaces, L4-Queues for traffic management.

Three-Level Scheduling Hierarchy : Pseudowire Service Logical Interfaces over a Pseudowire Service Interface Set

Figure 2 shows another variation of MPLS pseudowire three-level hierarchical scheduling that includes two pseudowire service logical interfaces over a pseudowire service interface set. This variation uses the following CoS scheduler nodes:

Level 4—Forwarding class-based queues
Level 3—Pseudowire service logical interfaces (ps0.1 and ps0.2)
Level 2—Pseudowire service interface set
Level 1—Common/shared physical interface of the logical tunnel anchor point

You apply the traffic-control profile at the pseudowire service interfaces (level 3) and at the interface set (level 2). This variation is most useful for subscriber edge deployments.

Figure 2: Three-Level Scheduling Hierarchy Case 2: Pseudowire Service Logical Interfaces over a Pseudowire Service Interface Set Network architecture diagram showing pseudowire logical interfaces interacting with queues, TCP connections, and a logical tunnel physical interface.

Network architecture diagram showing pseudowire logical interfaces interacting with queues, TCP connections, and a logical tunnel physical interface.

Three-Level Scheduling Hierarchy Combined Deployment Scenario

Figure 3 shows a deployment scenario that combines the three-level hierarchical scheduling scenarios in Figure 1 and Figure 2.

Figure 3: Three-Level Hierarchical Scheduling for MPLS Pseudowire Subscriber Interfaces—Deployment Scenario Network architecture diagram showing layers L1 to L4 in a pseudowire-based system. L1 is the physical layer, L2 is the transport interface set, L3 includes pseudowire service interfaces ps0.1, ps0.2, ps1.1, ps1.2, and L4 consists of queues managing traffic. The ps1.0 interface connects the transport interface to service interfaces using TCP for reliable communication.

Network architecture diagram showing layers L1 to L4 in a pseudowire-based system. L1 is the physical layer, L2 is the transport interface set, L3 includes pseudowire service interfaces ps0.1, ps0.2, ps1.1, ps1.2, and L4 consists of queues managing traffic. The ps1.0 interface connects the transport interface to service interfaces using TCP for reliable communication.

This variation uses the following CoS scheduler nodes:

Level 4—Forwarding class-based queues
Level 3—Pseudowire service logical interfaces (ps0.1, ps0.2, ps1.1, and ps1.2)
Level 2—Service interface set for pseudowire service interfaces (ps0.1 and ps0.2) and transport logical interface (ps1.0) for the pseudowire service logical interfaces (ps1.1 and ps1.2)
Level 1—Common/shared physical interface of the logical tunnel anchor point

You apply the traffic-control profiles to the interfaces at both level 2 and level 3, as well as the interface set at level 2.

ON THIS PAGE

CoS Three-Level Hierarchical Scheduling on MPLS Pseudowire Subscriber Interfaces

Three-Level Scheduling Hierarchy: Pseudowire Logical Interfaces over a Transport Logical Interface

Three-Level Scheduling Hierarchy : Pseudowire Service Logical Interfaces over a Pseudowire Service Interface Set

Three-Level Scheduling Hierarchy Combined Deployment Scenario

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