Chapter 42 Configuring PFC QoS

Understanding How PFC QoS Works

Understanding Classification and Marking

The following sections describe where and how classification and marking occur on the Cisco 7600 series routers:

•Classification and Marking at Trusted and Untrusted Ingress Ports, page 42-16

•Classification and Marking at Ingress OSM Ports, page 42-17

•Classification and Marking on the PFC Using Service Policies and Policy Maps, page 42-18

•Classification and Marking on the MSFC, page 42-19

Classification and Marking at Trusted and Untrusted Ingress Ports

The trust state of an ingress port determines how the port marks, schedules, and classifies received Layer 2 frames, and whether or not congestion avoidance is implemented. These are the port trust states:

•Untrusted (default)

•Trust IP precedence

•Trust DSCP

•Trust CoS

In all releases, ingress LAN port classification, marking, and congestion avoidance can use Layer 2 CoS values and do not set Layer 3 IP precedence or DSCP values.

In Release 12.2(18)SXF5 and later releases, you can configure WS-X6708-10GE ports to use received DSCP values for ingress LAN port classification and congestion avoidance (see the “Configuring DSCP-Based Queue Mapping” section on page 42-98)

In Releases earlier than Release 12.2(18)SXF5, ingress LAN port classification, marking, and congestion avoidance use Layer 2 CoS values only.

The following sections describe classification and marking at trusted and untrusted ingress ports:

•Classification and Marking at Untrusted Ingress Ports, page 42-16

•Ingress Classification and Marking at Trusted Ports, page 42-16

Classification and Marking at Untrusted Ingress Ports

PFC QoS Layer 2 remarking marks all frames received through untrusted ports with the port CoS value (the default is zero).

To map the port CoS value that was applied to untrusted ingress traffic to the initial internal DSCP value, configure a trust CoS policy map that matches the ingress traffic.

Ingress Classification and Marking at Trusted Ports

You should configure ports to trust only if they receive traffic that carries valid QoS labels. QoS uses the received QoS labels as the basis of initial internal DSCP value. After the traffic enters the router, you can apply a different trust state to traffic with a policy map. For example, traffic can enter the router through a trust CoS port, and then you can use a policy map to trust IP precedence or DSCP, which uses the trusted value as the basis of the initial internal DSCP value, instead of the QoS label that was trusted at the port.

 

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42-16

OL-4266-08

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Cisco Systems OL-4266-08 Understanding Classification and Marking, Classification and Marking at Untrusted Ingress Ports
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OL-4266-08 specifications

Cisco Systems OL-4266-08 is a robust and versatile certification that focuses on the essentials of implementing and troubleshooting Cisco collaborations solutions. As enterprises increasingly rely on unified communications, having professionals who are knowledgeable in the latest Cisco technologies becomes a necessity. This certification is part of the Cisco Certified Network Associate (CCNA) program, which serves as a foundational stepping stone for individuals aspiring to build a career in networking and collaboration technologies.

One of the main features of OL-4266-08 is its emphasis on collaboration foundations, which includes an understanding of voice, video, messaging, and conferencing technologies. Professionals who obtain this certification demonstrate proficiency in deploying, configuring, and troubleshooting Cisco collaboration solutions like Cisco Unified Communications Manager and Cisco Webex. This knowledge is critical as businesses seek to enhance communication and productivity through integrated systems.

Technologically, OL-4266-08 covers a wide array of essential concepts, including IP telephony, voicemail, and collaborative tools. Candidates learn about the architecture of unified collaboration systems, involving integration with routing and switching networks. Additionally, it delves into security protocols to ensure secure transmissions of voice and video data, thereby protecting sensitive corporate communication.

In terms of characteristics, OL-4266-08 is designed to be both comprehensive and practical. The certification emphasizes hands-on experience, which is essential for understanding real-world applications of Cisco technologies. The coursework provides extensive exposure to simulations and labs that mimic actual network environments. This hands-on approach enables candidates to troubleshoot issues effectively using Cisco's troubleshooting tools and methodologies.

Moreover, the certification aligns with industry standards, ensuring that individuals gain relevant and in-demand skills. Given the evolving landscape of network technologies, OL-4266-08 prepares individuals for future growth and specialization in various areas, including cloud collaboration and Internet of Things (IoT) communications.

In conclusion, Cisco Systems OL-4266-08 equips networking professionals with the necessary skills to implement and support Cisco collaboration solutions. The focus on hands-on experience, along with in-depth coverage of technology and security protocols, makes it a valuable certification in the fast-paced world of network communications. With the rise of remote work and digital collaboration, this certification is pivotal for anyone looking to enhance their career in networking and technology.
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