Chapter 42 Configuring PFC QoS

Understanding How PFC QoS Works

Microflow Policers

PFC QoS applies the bandwidth limit specified in a microflow policer separately to each flow in matched traffic. For example, if you configure a microflow policer to limit the TFTP traffic to 1 Mbps on VLAN 1 and VLAN 3, then 1 Mbps is allowed for each flow in VLAN 1 and 1 Mbps for each flow in VLAN 3. In other words, if there are three flows in VLAN 1 and four flows in VLAN 3, the microflow policer allows each of these flows 1 Mbps.

You can configure PFC QoS to apply the bandwidth limits in a microflow policer as follows:

•You can create microflow policers with up to 63 different rate and burst parameter combinations.

•You create microflow policers in a policy map class with the police flow command.

•You can configure a microflow policer to use only source addresses, which applies the microflow policer to all traffic from a source address regardless of the destination addresses.

•You can configure a microflow policer to use only destination addresses, which applies the microflow policer to all traffic to a destination address regardless of the source addresses.

•For MAC-Layer microflow policing, PFC QoS considers MAC-Layer traffic with the same protocol and the same source and destination MAC-Layer addresses to be part of the same flow, including traffic with different EtherTypes. With a PFC3, you can configure MAC ACLs to filter IPX traffic.

•With a PFC2, you can configure IPX ACLs to filter IPX traffic. For IPX microflow policing,

PFC QoS considers IPX traffic with the same source network, destination network, and destination node to be part of the same flow, including traffic with different source nodes or source sockets.

•By default, microflow policers only affect traffic routed by the MSFC. To enable microflow policing of other traffic, including traffic in bridge groups, enter the mls qos bridged command. With a PFC2, you must enable bridged mircoflow policing for routed traffic as well.

•With a PFC3, you cannot apply microflow policing to ARP traffic.

•You cannot apply microflow policing to IPv6 multicast traffic.

You can include both an aggregate policer and a microflow policer in each policy map class to police a flow based on both its own bandwidth utilization and on its bandwidth utilization combined with that of other flows.

Note If traffic is both aggregate and microflow policed, then the aggregate and microflow policers must both be in the same policy-map class and each must use the same conform-actionand exceed-actionkeyword option: drop, set-dscp-transmit, set-prec-transmit, or transmit.

For example, you could create a microflow policer with a bandwidth limit suitable for individuals in a group, and you could create a named aggregate policer with bandwidth limits suitable for the group as a whole. You could include both policers in policy map classes that match the group’s traffic. The combination would affect individual flows separately and the group aggregately.

For policy map classes that include both an aggregate and a microflow policer, PFC QoS responds to an out-of-profile status from either policer and, as specified by the policer, applies a new DSCP value or drops the packet. If both policers return an out-of-profile status, then if either policer specifies that the packet is to be dropped, it is dropped; otherwise, PFC QoS applies a marked-down DSCP value.

Note To avoid inconsistent results, ensure that all traffic policed by the same aggregate policer has the same trust state.

 

 

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Cisco Systems OL-4266-08 manual Microflow Policers, 42-21
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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.

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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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