Chapter 12 Configuring Quality of Service on the ML-Series Card

ML-Series QoS

Weights are assigned to each queue as a result of the service provisioning process. When coupled with policing and policy mapping provisioning, these weights and the WDRR scheduling process ensure that QoS commitments are provided to each service flow.

Figure 12-5illustrates the ML-Series card’s queuing and scheduling.

Figure 12-5 Queuing and Scheduling Model

Queues assigned by

"Priority" Command for associated Classification for Scheduling

Queues assigned by

"Bandwith" Command for associated Classification for Scheduling

Queues automatically

assigned

Low Latency Queues

Unicast Queues

Multi/Broadcast Queues

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Weighted

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Deficit

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The weighting structure allows traffic to be scheduled at 1/2048 of the port rate. This equates to approximately 49 kbps for traffic exiting a FastEthernet port.

The unicast queues are created as the output service policy implementation on the egress ports. Each unicast queue is assigned with a committed bandwidth and the weight of the queue is determined by the normalization of committed bandwidth of all defined unicast queues for that port. The traffic beyond the committed bandwidth on any queue is treated by the scheduler according to the relative weight of the queue.

The LLQ is created as the output service policy implementation on the egress ports. Each LLQ is assigned with a committed bandwidth of 100 percent and is served with lower latency. To limit the bandwidth usage by the LLQ, a strict policer needs to be implemented on the ingress for the LLQ traffic classes.

The DE allows some packets to be treated as committed and some as discard-eligible on the scheduler. For the Ethernet frames, the CoS (IEEE 802.1p) bits are used to identify committed and discard eligible packets, where the RPR-CoS and the DE bits are used for RPR traffic. When congestion occurs and a queue begins to fill, the DE packets hit a lower tail-drop threshold than the committed packets. Committed packets are not dropped until the total committed load exceeds the interface output. The tail-drop thresholds adjust dynamically in the card to maximize use of the shared buffer pool while guaranteeing fairness under all conditions.

Control Packets and L2 Tunneled Protocols

The control packets originated by the ML-Series card have a higher priority than data packets. The external Layer 2 and Layer 3 control packets are handled as data packets and assigned to broadcast queues. Bridge protocol data unit (BPDU) prioritization in the ML-Series card gives Layer 2-tunneled BPDU sent out the multicast/broadcast queue a higher discard value and therefore a higher priority than than other packets in the multicast/broadcast queue. The Ethernet CoS (IEEE 802.1p) for

Layer 2-tunneled protocols can be assigned by the ML-Series card.

Cisco ONS 15310-CL, ONS 15310-MA, and ONS 15310-MA SDH Ethernet Card Software Feature and Configuration Guide, R9.1 and R9.2

 

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ONS 15310-CL, ONS 15310-MA, Cisco ONS 15310-MA specifications

Cisco Systems has long been a leader in networking and telecommunications technology, and among its impressive lineup of products, the Cisco ONS 15310 series stands out as an essential solution for optical networking. This series includes models such as the ONS 15310-MA, ONS 15310-CL, and ONS 15310-CA, each designed to meet the diverse needs of service providers and enterprises seeking to enhance their optical transport networks.

The Cisco ONS 15310-MA is an advanced multi-service platform designed for metropolitan area networks. It facilitates the seamless transport of data, voice, and video over optical networks. One of its main features is its ability to support a variety of interfaces, including Ethernet, SONET/SDH, and Wavelength Division Multiplexing (WDM), allowing users to integrate multiple services into a single platform. Additionally, the ONS 15310-MA supports advanced traffic management and Quality of Service (QoS) features to prioritize critical applications and ensure consistent performance.

The ONS 15310-CL variant is tailored for more specific applications, providing enhanced capabilities aimed at delivering carrier-grade services. It features a robust architecture that accommodates high-capacity traffic without compromising reliability. This model emphasizes low power consumption and a compact design, making it suitable for deployment in space-constrained environments. The ONS 15310-CL also supports a wide range of optical interfaces, making it highly flexible for various network configurations.

In terms of technologies, the Cisco ONS 15310 series leverages Optical Transport Network (OTN) capabilities, providing high efficiency and greater bandwidth utilization. OTN technology enables efficient error correction and adds resilience to the network through its built-in protection mechanisms. Furthermore, the series supports seamless integration with existing IP/MPLS networks, creating a cohesive infrastructure as organizations evolve their networking requirements.

One of the defining characteristics of the ONS 15310 series is its focus on scalability. Network operators can start with a modest deployment and gradually expand capacity as demand grows. This adaptability is complemented by Cisco's comprehensive management and monitoring tools, providing operators with real-time insights into network performance and facilitating proactive management.

In conclusion, the Cisco ONS 15310-MA and ONS 15310-CL models represent sophisticated solutions for modern optical networks. With their versatile features, advanced technologies, and robust design, they empower service providers and enterprises to build resilient, high-capacity networks that meet the demands of today’s data-driven world.
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