Deploying Endto End QoS Cont

E2E QoS = Enterprise QoS + Service Provider QoS

E2E QoS = Enterprise QoS + Service Provider QoS

QoS—Campus Access

• Speed and Duplex Settings

• Classification / Trust on IP

QoS—Campus Distribution

• Layer 3 Policing, Marking

• Multiple Queues on Switch Ports

QoS—WAN Edge

• Classification, Marking

QoS—SP Cloud

• Capacity Planning

• DiffServ Backbone

QoS—Campus Access

• Speed and Duplex Settings

• Classification / Trust on IP

• Phone and Access Switch

• Multiple Queues on Switch Ports

• Priority Queuing for VoIP

QoS—Campus Distribution

• Layer 3 Policing, Marking

• Multiple Queues on Switch Ports

• Priority Queuing for VoIP

• WRED within Data Queue for Congestion Avoidance

QoS—WAN Edge

• Classification, Marking

• Low-Latency Queuing

• Link Fragmentation and Interleaving

• WRED and Shaping

QoS—SP Cloud

• Capacity Planning

• DiffServ Backbone

• Low-Latency Queuing orMDRR

To provide end-to-end QoS, both the enterprise and the service provider must implement the proper QoS mechanisms to ensure the proper per-hop behavior (PHB) for each traffic class across the whole network. Until recently, QoS was not an issue in an enterprise campus network where bandwidth is plentiful. But as more applications such as IP telephony, videoconferencing, e-learning, and mission-critical data applications are being implemented in the campus, it has become evident that buffer management, not just bandwidth, is an issue that must be addressed. QoS functions such as classification, scheduling, and provisioning are also now required within the campus to manage bandwidth and buffers to minimize loss, delay, and jitter.

The figure lists some of the requirements within the different building blocks that make up the end-to-end network. Most of the more complex QoS configurations occur at the WAN edge. In the IP core (service provider cloud), only queuing, such as LLQ/class-based weighted fair queuing (CBWFQ) or modified deficit round robin (MDRR), and weighted random early detection (WRED should be required.

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