It will be there by 1030 am

Some applications, such as high-resolution video, require consistent, dedicated bandwidth to provide sufficient quality for viewers. IntServ was introduced to guarantee predictable network behavior for these applications. Because IntServ reserves bandwidth throughout a network, no other traffic can use the reserved bandwidth. Bandwidth that is unused, but reserved, is wasted. IntServ is similar to a concept known as hard QoS . With hard QoS, traffic characteristics such as bandwidth, delay, and...

Available in Cisco IOS Release 1224T

Dual-rate class-based policing was introduced in Cisco IOS 12.2(4)T. With dual-rate policing, traffic policing can be enforced according to two separate rates CIR and PIR. The use of these two rates can be specified, along with their corresponding values, by using two keywords, cir and pir, in the police command. The Bc and Be keywords and their associated arguments (conform-burst and peak-burst, respectively) are optional. If Bc is not specified, Bc (in bytes) will default to CIR 32, or 1500...

DSCP is backward compatible with IP precedence

At the network layer, IP packets are typically classified based on source or destination IP address, packet length, or the contents of the ToS byte. Link-layer media often changes as a packet travels from its source to its destination. Because a CoS field does not exist in a standard Ethernet frame, CoS markings at the link layer are not preserved as packets traverse non-trunked or non-Ethernet the network. Using marking at the network layer (Layer 3) provides a more permanent marker that is...

Configuring Single Rate Class Based Policing

Police avg-rate BC BE conform-action action exceed-action action violate-action action avg-rate Traffic rate in bps (8000 to 200,000,000) BC normal burst sets the size in bytes - Default is 1500 bytes, or CIR 32, whichever is higher Be Excess burst sets the size in bytes - transmit (default conform action) - drop (default exceed and violate action) - set-prec-transmit ip-precedence - set-mpls-exp-transmit mple-exp The MQC-based police command defines policing parameters for a specific traffic...

Example Dual Rate Token Bucket as a Piggy Bank

Using a dual-rate token bucket is like using two piggy banks, each with a different savings rate. However, you can only take out money from one of the piggy banks at a time. For example, you can save ten dollars per day into the first piggy bank (PIR peak spending rate 10 per day) and then at the same time, you can save five dollars per day into the second piggy bank (CIR normal average spending rate 5 per day). However, the maximum amount you can spend is 10 per day, not 15 per day, because...

The packet precedence has no effect on the dropping scheme

Wfq Weight Calculation

WFQ uses these two parameters that affect the dropping of packets The congestive discard threshold (CDT) is used to start dropping packets of the most aggressive flow, even before the hold-queue limit is reached. The hold-queue out limit (HQO) defines the maximum number of packets that can be in the WFQ system at any time. There are two exceptions to the WFQ insertion and drop policy, as follows If the WFQ system is above the CDT limit, the packet is still enqueued if the per-flow queue is...

Cisco Icons and Symbols

For additional information on Cisco terminology, refer to the Cisco Internetworking Terms and Acronyms glossary of terms at You are encouraged to join the Cisco Certification Community, a discussion forum open to anyone holding a valid Cisco Career Certification (such as Cisco CCIE , CCNA , CCD A , CCNP , CCDP , CCIP , or CCSPTM). It provides a gathering place for Cisco certified professionals to share questions, suggestions, and information about Cisco Career Certification programs and other...

Example Token Bucket as a Piggy Bank

Think of a token bucket as a piggy bank. Every day you can insert a dollar into the piggy bank (the token bucket). At any given time, you can only spend what you have saved up in the piggy bank. On the average, if your saving rate is a dollar per day, your long-term average spending rate will be one dollar per day if you constantly spend what you saved. However, if you do not spend any money on a given day, you can build up your savings in the piggy bank up to the maximum limit that the piggy...

When policing and remarking excess traffic remark to the same AF class with higher drop probability

- Example Re-mark AF 31 exceeding traffic to AF 32 (do not re-mark AF 31 to AF 21) In an IP service provider environment, the recommended architecture includes the deployment of a DiffServ backbone with a different overprovisioning ratio for different traffic classes. Most service providers typically classify their customer traffic into three or four traffic classes (such as controlled latency, controlled load, and best effort). At the network edge, the service provider may define additional...

QoS and BGP Interaction

Cisco Express Forwarding

This topic describes the interaction between QoS and BGP. This topic describes the interaction between QoS and BGP. When using QPPB, the QoS feature works independently from BGP routing. BGP is only used to propagate the QoS policy. In QBBP configurations, you specify whether to use IP precedence or the QoS group ID obtained from the source (input) address or destination (output) address entry in the route table. You can specify either the input or output address. This topic describes CEF...

Classification and Marking at the Data Link Layer Frame RelayATM QoS

Frame Relay DTE devices can set the DE bit of a frame so that if the network becomes congested, Frame Relay devices will discard frames with the DE bit set before discarding those that do not have the DE bit set. Frame Relay DTE devices can set the DE bit of a frame so that if the network becomes congested, Frame Relay devices will discard frames with the DE bit set before discarding those that do not have the DE bit set. Preserved throughout the Frame Relay network. Preserved throughout the...

Catalyst 3550 Access Switch

1P3Q2T (recommended) or 4Q2T WRR default - Each queue is given a relative weight with one priority queue Default values are as follows CoS Value CoS Priority Queues 0, 1 1 2, 3 2 Move CoS 5 traffic to queue 4 Trust Cisco IP Phone on access links Trust DSCP or CoS on uplinks CoS-to-DSCP mappings Classify and mark mission-critical traffic using ACLs For the Catalyst 3550 switches, the recommended configuration for the transmit interface is one priority queue and three queues, each with a single...

Configuring DSCPBased CBWRED

This topic describes the Cisco IOS commands that are required to configure DSCP-based CB-WRED. Command can be used at the interface, per-VC (with random-detect-group), or the class level (service-policy). Default service profile is used. The WRED random-detect command and the WFQ queue-limit command are mutually exclusive for class policy. Use the random-detect dscp-based command to enable DSCP-based WRED on an interface. By default, WRED is precedence-based and uses eight default WRED...

Student Guide

Editorial, Production, and Graphic Services 06.28.06 Example Three Steps to Implementing QoS on a Network 2 Implementing Cisco Quality of Service (QOS) v2.2 Identifying Models for Implementing QoS Understanding the Integrated Services Model Understanding the Differentiated Services Model Backward Compatibility Using the Class Selector Applying QoS to Input and Output Interfaces Understanding QoS in the Life of a Packet Life of a High-Priority (VoIP) Packet Introduction to Modular QoS CLI and...

AutoQoS Enterprise Router Platforms

This topic describes the router platforms on which AutoQoS can be used. The figure shows the listed Cisco router platforms that support the AutoQoS Enterprise feature. When verifying whether the Cisco IOS software Release 12.3(7)T supports AutoQoS Enterprise, check the Cisco Feature Navigator tool on the Cisco.com website. When searching for a Cisco IOS software version that will support the AutoQoS Enterprise feature, make sure, when using the Cisco IOS Feature Navigator tool, that you select...

CBWFQ Architecture 75 Percent Rule

Cisco Bandwidth

- RSVP maximum reserved bandwidth Result must be less than or equal to 75 of interface bandwidth (or Frame Relay, DLCI, CIR) - Leaves headroom for overhead traffic such as Layer 2 keepalives and bandwidth for the class default traffic max-reserved-bandwidth command overrides 75 limit, but seldom recommended Properly provisioning the network bandwidth is a major component of successful network design. You can calculate the required bandwidth by adding the bandwidth requirements for each major...