A queue is reserved for each class and traffic belonging to a class is directed to that class queue

CBWFQ extends the standard WFQ functionality to provide support for user-defined traffic classes. With CBWFQ, you define the traffic classes based on match criteria, including protocols, ACLs, and input interfaces. Packets satisfying the match criteria for a class constitute the traffic for that class. A queue is reserved for each class, and traffic belonging to a class is directed to that class queue. After a class has been defined according to its match criteria, you can assign...

All packets marked with one of the selected IP precedence values are matched by this class map

Class-map Mission-Critical match ip precedence 3 4 class-map Transactional match ip precedence 1 2 A much faster method of classification is by matching the IP precedence. Up to four separate IP precedence values or names can be used to classify packets based on the IP Precedence field in the IP header on a single match-statement line. The figure contains a mapping between IP precedence values and names. The running configuration, however, only shows IP precedence values (not names). match ip...

Ambiguous path

Teardown messages RSVP teardown messages remove the path and reservation state without waiting for the cleanup timeout period. Teardown messages can be initiated by an application in an end system (sender or receiver) or a router as the result of state timeout. RSVP supports the following two types of teardown messages path-teardown Path-teardown messages delete the path state (which deletes the reservation state), travel toward all receivers downstream from the point of initiation, and are...

An SNMP structure that describes the particular device being monitored

An MIB is a Simple Network Management Protocol (SNMP) structure that describes the particular device being monitored. Cisco provides many standards-based MIBs for use in monitoring the status of devices on a network. Advanced network management products, such as CiscoWorks QPM, use these MIBs to generate statistics about the performance of the network. Specialized QoS MIBs enable QPM to graphically display key QoS information to aid in the management of QoS policies on the network. Note See the...

Applying Congestion Avoidance

RED is most useful in enterprise and service provider networks on output interfaces where congestion is expected to occur. Edge routers or switches typically classify and mark packets as the packets enter the network. Congestion avoidance mechanisms can use these packet markings to indicate a set of drop criteria for a traffic stream. Congestion avoidance mechanisms are also applicable to the campus or LAN environment. In these networks, congestion avoidance is best used on interfaces that...

Applying Link Efficiency Mechanisms

Header compression and LFI are typically configured at the WAN edge for WAN links below T1 or E1 speeds to optimize the use of the WAN link and to prevent long serialization delay. Layer 2 payload compression is less commonly deployed on WAN links, especially without the use of hardware-assisted payload compression.

Applying QoS to Input and Output Interfaces

(As close to the source as possible) (Coming from a higher-speed link or aggregation) In a QoS-enabled network, classification is performed on every input interface. Marking should be performed as close to the network edge as possible in the originating network device, if possible. Devices farther from the edge of the network, such as routers and switches, can be configured to trust or untrust the markings made by devices on the edge of the network. An IP Phone, for example, will not trust the...

Attaching Service Policies to Interfaces

This topic describes the MQC commands used to attach a service policy to an interface. Attaching Service Policies to Interfaces service-policy input output policy-map-name Attaches the specified service policy map to the input or output interface interface Serial0 0 service-policy output PM bandwidth 2000 class class-default bandwidth 6000 Use the service-policy interface configuration command to attach a traffic policy to an interface and to specify the direction in which the policy should be...

Automation with Cisco AutoQoS Routers Diff Serv Functions Automated

Cisco IOS Catalyst Behavior Software QoS Feature Set Layer 3 and Layer 2 attributes to categorize packets into a class. Set Layer 3 and Layer 2 attributes to categorize packets into a class. Provide EF treatment to voice and Best-Effort treatment to data. Shape to CIR to prevent burst and smooth traffic to configured rate. Reduce the VoIP bandwidth requirement. Reduce jitter experienced by voice packets. AutoQoS performs these functions in a WAN Automatically classifies Real-Time Transport...

Available in Cisco IOS Release 12213T

Policy-map police1 class bulk-ftp police cir percent 20 pir percent 40 conform-action set-dscp-transmit af11 exceed-action set-dscp-transmit 0 violate-action drop interface Ethernet 0 0 service-policy input policel interface Serial 0 0 service-policy input police1 The percentage-based policing feature was introduced in Cisco IOS Release 12.2(13)T. Before this feature, traffic policing was configured on the basis of a user-specified amount of bandwidth available on the interface. Policy maps...

Before Converged Networks

Traditional data traffic characteristics First-come, first-served access Mostly not time-sensitive - delays OK Brief outages are survivable Order Entry, Finance, Manufacturing, HR, Training, Other Traditional data traffic characteristics First-come, first-served access Mostly not time-sensitive - delays OK Brief outages are survivable Order Entry, Finance, Manufacturing, HR, Training, Other Before networks converged, network engineering focused on connectivity. The rates at which data came onto...

Behavior of a TCP Receiver

Receiver schedules an ACK on receipt of next message. TCP acknowledges the next segment it expects to receive, not the last segment it received. - In the example, N+1 is blocked, so the receiver keeps acknowledging N+1 (the next segment it expects to receive). When the receiver receives a data segment, the receiver checks that data segment sequence number (byte count). If the data received fills in the next sequence of numbers expected, the receiver indicates that the data segment was received...

Benefits and Drawbacks of WFQ

Simple configuration (classification does not have to be configured) Guarantees throughput to all flows Drops packets of most aggressive flows Supported on most platforms Supported in all IOS versions Multiple flows can end up in one queue Does not support the configuration of classification Cannot provide fixed bandwidth guarantees Complex classification and scheduling mechanisms Simple configuration (no manual classification is necessary) Guarantees throughput to all flows Drops packets of...

Best Effort

The service provider provides QoS service level agreement (SLA) for the controlled-latency, controlled-load 1 (AF31), controlled-load 2 (AF21), and Best-Effort traffic classes. The service provider maps the enterprise customer QoS classifications into the four defined traffic classes of the service provider. The service provider router recognizes the packet as a high-priority voice packet and assigns the packet to the real-time EF class. The packet is re-marked to DSCP 46 to fit the service...

Bgppolicy source destination ipprecmap ipqosmap

The IP precedence bit or QoS group ID from the source address entry in the route table The IP precedence bit or QoS group ID from the destination address entry in the route table QoS policy based on the IP precedence The QoS policy based on the QoS group ID Note If you specify both source and destination on the interface, the software looks up the source address in the routing table and classifies the packet based on the source address first then the software looks up the destination address in...

Campus QoS Implementation

A robust, modern switching design is a requirement. A robust, modern switching design is a requirement. Buffer management is more of a concern than bandwidth management. Multiple queues are required on all interfaces to prevent Tx queue congestion and drops. Voice traffic should always go into the highest priority queue. Trust Cisco IP Phone CoS setting but not the PC CoS setting. Classify and mark traffic as close to the source as possible. Use class-based policing to rate-limit certain...

Catalyst 2950 and 3550 Switches

During QoS processing, the switch represents the priority of all traffic (including non-IP traffic) with an internal DSCP value. During classification, QoS uses configurable mapping tables to derive the internal DSCP (a six-bit value) from received CoS value. Before the traffic reaches the scheduling stage, QoS uses the configurable DSCP-to-CoS map to derive a CoS value from the internal DSCP value. The show policy-map interface command displays all service policies applied to the interface. In...

Causes jitter bursts or packet trains temporarily fill the queue

Although FIFO queuing might be regarded as the fairest queuing mechanism, it has these FIFO is extremely unfair when an aggressive flow contests with a fragile flow. Aggressive flows send a large number of packets, many of which are dropped. Fragile flows send a modest number of packets and most of them are dropped because the queue is always full due to the aggressive flow. This type of behavior is called starvation. Short or long bursts cause a FIFO queue to fill. Packets entering an...

CBWFQ and LLQ

Basic methods are combined to create more versatile queuing mechanisms. Basic methods are combined to create more versatile queuing mechanisms. Neither the basic queuing methods nor the more advanced WFQ completely solve quality of service (QoS) problems resulting from converged network traffic. These problems remain If only priority queuing (PQ) is used for a voice-enabled network, voice will get the priority needed, but data traffic will likely starve out at some point. If only custom queuing...

EtoPE QoS for Frame Relay Access CE Outbound

Match ip access-group 101 class-map match-all BUSINESS match ip acces s-group 102 policy-map OUT-POLICY class PREMIUM priority percent 25 set ip dscp ef class BUISNESS bandwidth remaining percent 75 set ip dscp af31 random-detect dscp-based class class-default bandwidth remaining percent 25 set ip dscp 0 random-detect dscp-based The figure shows the QoS configurations on the managed CE router outbound interface to implement the required QoS policy required for each of the three service provider...

EtoPE QoS for Frame Relay Access PE Inbound

The figure shows the QoS configurations on the ingress PE router inbound interface to implement the required QoS policy that is required for each of the three service provider traffic classes. In this case, a traffic policy called IN-POLICY is configured to provide the required class-based policing. For the premium class, the rate limit is set to 25 percent of the link bandwidth. All exceeding premium-class traffic is dropped. For the business class, the rate limit is set to 38 percent of the...

Cisco AutoQoS with Cisco Works QPM

Use AutoQoS Enterprise to configure routers Use QPM to manage network-wide QoS for multiple devices. Use QPM to manage network-wide QoS for multiple devices. Customers can more easily provision and manage successful QoS deployments using Cisco AutoQoS together with QPM. Cisco AutoQoS provides QoS provisioning for individual routers and switches, simplifying deployment and reducing human error. CiscoWorks QPM provides centralized QoS design, administration, and traffic monitoring that scales to...

Cisco IOS Traffic Policing Mechanisms

Conform, exceed, violate Drop, set, transmit Single or dual token bucket Single or dual rate policing Multi actions The figure lists the characteristics of the class-based traffic-policing mechanism that is available in Cisco IOS software. Class-based policing is also available on some Cisco Catalyst switches. Class-based policing supports a single or dual token bucket. Class-based policing also supports single-rate or dual-rate metering and multiaction policing. Multiaction policing allows...

Cisco IOS Traffic Shaping Mechanisms

Subinterface or group or class-based The figure lists some of the different traffic-shaping mechanisms available in Cisco IOS software the newer class-based traffic shaping, Distributed Traffic Shaping (DTS), and FRTS. Class-based traffic shaping uses MQC to allow traffic to be shaped per traffic class as defined by the class map. You can use class-based traffic shaping in combination with class-based weighted fair queuing (CBWFQ), in which the shaped rate is used to define an upper rate limit...

Citrix ICA Interdependent Computing Architecture

New features are usually added to new versions of the Cisco IOS software. NBAR is the first mechanism that supports dynamic upgrades without having to change the Cisco IOS version or restart a router. PDLMs contain the rules that are used by NBAR to recognize an application and can be used to bring new or changed functionality to NBAR. You can load an external PDLM at run time to extend the NBAR list of recognized protocols. You can use PDLMs to enhance an existing protocol recognition...

Classbased configuration of WRED is identical to standalone WRED

Congestion avoidance techniques monitor the network interface load in an effort to anticipate and avoid congestion at common network bottlenecks. Congestion avoidance is achieved through intelligent packet dropping techniques. Traditionally, Cisco IOS software used standalone RED and WRED mechanisms to avoid congestion on an interface. Those mechanisms can perform a differentiated drop based on the IP precedence or DSCP value. The class-based weighted fair queuing (CBWFQ) system supports the...

Classbased policing is configured using the MQC method

The class-based policing feature performs these functions Limits the input or output transmission rate of a class of traffic based on user-defined criteria Marks packets by setting different Layer 2 or Layer 3 markers, or both You can implement class-based policing using a single or double token bucket method as the metering mechanism. When the violate action option is not specified in the police MQC command, the single token bucket algorithm is engaged when the violate action option is...

Class Based QoS Mib CbqoSMIB

Provides read access to configuration and statistical information for MQC-based QoS policies Provides MQC configuration information and application statistics Provides CBQoS statistics on a per-policy, per-interface, or PVC basis Allows monitoring of pre- and post-policy bit rates on a device Provides read access to configuration and statistical information for MQC-based QoS policies Provides MQC configuration information and application statistics Provides CBQoS statistics on a per-policy,...

Class Based RTP Header Compression

Most of the information in the headers (IP, UDP, and RTP) is static throughout the session. IP (20 bytes), UDP (8 bytes), and RTP (12 bytes) use 40 bytes. RTP header compression can squeeze these three headers into 2 or 4 bytes. Class-based RTP header compression allows compression on a traffic class. Class-based RTP header compression is configured via MQC. RTP is the standard protocol (RFC 1889) for the transport of real-time data. RTP is intended to provide...

Class Based TCP Header Compression Example Cont

Overhead 46 (46 + 5) Overhead 90 Delay (46 + 5) 64 kbps Delay 6 ms Overhead 10 (10+ 5) Overhead 67 Delay (10 + 5) 64kbps * 8 Delay 2 ms The figure shows the packet size before and after TCP header compression. After TCP header compression, the IP and TCP headers are reduced to 4 bytes, resulting in 10 bytes of overall headers. The overhead is reduced from 90 percent to 67 percent when small packets are used. Because of the packet size reduction, the serialization delay decreases from 6 ms to 2...

Classbased TCP header compression is configured via MQC

In TCP header compression, the IP and TCP headers, which normally use 20 bytes each, are reduced to a session index, and the variable part of the header. With all optimizations, the combined header length of 40 bytes can be reduced to a 3- to 5-byte compressed header. After you configure a class within a policy map, class-based TCP header compression occurs on a per-class basis. Policy maps are created using the MQC. Attach the policy maps to an interface by using the service-policy command....

Classification

Classification is the identifying and splitting of traffic into different classes. Classification is the identifying and splitting of traffic into different classes. Traffic can be classed by various means, including the DSCP. Modular QoS CLI allows classification to be implemented separately from policy. Classification is the identifying and splitting of traffic into different classes. In a QoS-enabled network, all traffic is classified at the input interface of every QoS-aware device. Packet...

Classification and Marking at the Data Link Layer Cisco ISL Class of Service

ISL encapsulation adds 30 bytes to Ethernet frame ISL header contains VLAN field VLAN field consists of VLAN ID and CoS Supports up to 8 classes of service Focuses on support for QoS over ISL trunks Preserved through the LAN, not end to end ISL encapsulation adds 30 bytes to Ethernet frame ISL header contains VLAN field VLAN field consists of VLAN ID and CoS Supports up to 8 classes of service Focuses on support for QoS over ISL trunks Preserved through the LAN, not end to end 006 Cisco...

Classification and marking can also be performed using MQC class maps and policy maps

Create an IP standard or extended ACL for IP traffic, or a Layer 2 MAC ACL for non-IP traffic. 2. Create a class map and define the match criteria to classify traffic. 3. Create a service policy to perform the appropriate QoS action (mark, police, and so on). 4. Apply the service policy to a switch interface. Create a class map by using the class-map global configuration command. The class-map global configuration command is used to isolate a specific traffic flow (or class) from all other...

Classification and Marking on Catalyst 2950 Switches

Port can be configured to trust CoS, DSCP, or Cisco IP Phone (default untrusted) Has default CoS-to-DSCP and DSCP-to-CoS maps Can use class-based marking to set DSCP No VLAN-based classification Limited ACLs no port range IP precedence is encoded into the three high-order bits of the type of service (ToS) field in the IP header. It supports eight classes. two of which (IP precedence 6 and 7) are reserved for control-plane traffic and should not be used for user-defined classes. IP Precedence 0...

Classification and Marking on Catalyst Switches

IP Precedence (Module-Dependent) Extend Trust to IP Phone The IEEE 802.1P specification specifies a standard for delivering QoS in LANs. Packets are marked with three CoS bits where CoS values range from zero for low priority to seven for high priority. CoS can only be applied on trunks because VLAN trunking encapsulations designate fields with available space to carry CoS bits. There are currently two widely deployed trunking protocols that can transport CoS markings, as follows ISL frame...

Class Selector IP Precedence PHB

These PHBs are defined by IETF standards Default PHB Used for Best-Effort service (bits 5 to 7 of DSCP 000) Expedited Forwarding (EF) PHB Used for low-delay service (bits 5 to 7 of DSCP 101) Assured Forwarding (AF) PHB Used for guaranteed bandwidth service (bits 5 to 7 of DSCP 001, 010, 011, or 100) Class-selector PHB Used for backward compatibility with non-DiffServ-compliant devices (RFC 1812-compliant devices bits 2 to 4 of DSCP 000 )

Comparing Methods for Implementing QoS

Cisco recommends the use of MQC and AutoQoS VoIP when deploying voice over the LAN, and AutoQoS Enterprise on router WAN interfaces. While MQC is much easier to use than CLI, AutoQoS VoIP and AutoQoS Enterprise can simplify the configuration of QoS. As a result, you can accomplish the fastest implementation with AutoQoS. MQC offers excellent modularity and the ability to fine-tune complex networks. AutoQoS offers the fastest way to implement QoS, but has limited fine-tuning capabilities. When...

Configurable queue weight

On the Catalyst 2950 series switches, the default scheduling method is strict priority. Strict priority scheduling is based on the priority of queues. Packets in the high-priority queue always transmit first packets in the low-priority queue do not transmit until all the high-priority queues become empty. CoS values can be assigned to queues during configuration. The default CoS-to-queue assignment is CoS 6 to 7 placed in queue 4 CoS 4 to 5 placed in queue 3 CoS 2 to 3 placed in queue 2 CoS 0...

Configuring and Monitoring Class Maps

This topic describes the Cisco IOS MQC commands required to configure and monitor a class map. Use the class-map global configuration command to create a class map and enter the class-map configuration mode. A class map is identified by a case-sensitive name therefore, all subsequent references to the class map must use exactly the same name. At least one match command should be used within the class-map configuration mode (match none is the default). The description command is used for...

Configuring and Monitoring Policy Maps

This topic describes the Cisco IOS MQC commands required to configure and monitor a policy map. You can configure service policies by using the policy-map command. Use up to 256 classes within one policy map by using the class command with the name of a preconfigured class map. You can also use a nonexistent class within the policy-map configuration mode if the match condition is specified after the name of the class. The running configuration will reflect such a configuration by using the...

Configuring CBWRED

This topic describes the Cisco IOS commands that are required to configure CB-WRED. To configure CB-WRED (WRED at the class level with CBWFQ), configure the DSCP-based and precedent-based arguments within MQC. Specific CB-WRED configuration arguments are applied within a policy map. You can then apply the policy map configuration wherever policy maps are attached (for example, at the interface level, the per-virtual circuit VC level, or the shaper level). Enables IP precedence-based WRED in the...

Configuring Class Based Header Compression

Headers exist on almost every communication layer of the OSI stack. When data is sent between workstations, headers will typically be applied at the session, transport, network, and data-link layers. Real-Time Transport Protocol (RTP) is a protocol for the transport of real-time data. RTP includes a data portion and a header portion. The data portion of RTP is a thin protocol that provides support for the real-time properties of applications, such as continuous media, including timing...

Configuring Class Based Policing

Cisco IOS software supports two different traffic-policing mechanisms committed access rate (CAR) and class-based policing. CAR is an older Cisco traffic-policing feature, and class-based policing is a newer Cisco traffic-policing mechanism based on the modular quality of service (QoS) command-line interface (CLI), or MQC. Cisco recommends that you use MQC features when possible to implement QoS in the network. You should avoid using traffic-policing configurations with CAR, because no new...

Configuring Classification Using a UDP Port Range

Match ip rtp starting-port-number port-range Use this command to implement classification equal to IP RTP Priority. All UDP packets with source or destination port numbers within the specified range are matched. Range is between the starting-port (values from 2000 to 65535) and the sum of the starting-port and the port-range (values from 0 to 16383). The command should be used in combination with class-based low-latency queuing to implement RTP Priority using MQC. IP RTP Priority was introduced...

Configuring Classification Using DSCP

Match ip dscp ip-dscp-value ip-dscp-value Select up to eight DSCP values or names. All packets marked with one of the selected DSCP values are matched by this class map. IP packets can also be classified based on the IP DSCP field. A QoS design can be based on IP precedence marking or DSCP marking. DSCP standards make IP precedence marking obsolete but include backward compatibility with IP precedence by using the Class Selector (CS) values (which are 6-bit equivalents to their IP precedence...

Configuring CoSto Queue Mappings for PQ on Catalyst 2950 Switches

This topic describes the commands required to configure CoS-to-queue mappings for PQ on the Cisco Catalyst 2950 switch. To configure CoS-to-queue mappings for PQ on the Catalyst 2950 switch, specify the queue ID of the CoS priority queue. Ranges are 1 to 4 where 1 is the lowest CoS priority queue. Then, specify the CoS values that are mapped to the queue ID. The queue ID of the CoS priority queue. Ranges are 1 to 4 where 1 is the lowest CoS priority queue. The CoS values that are mapped to the...

Configuring Frame Relay Adaptive Class Based Shaping

This topic describes the Cisco IOS commands that are required to configure Frame Relay adaptive class-based shaping on Frame Relay interfaces. Configuring Frame Relay Adaptive Class-Based Shaping Adapts the shaping rate when BECN bits are received. min-rate Each BECN bit causes the shaping rate to be reduced to three-quarters of the previous rate but not below the min-rate. This command has effect only if used on Frame Relay interfaces. Responds to FECN bits by creating test frames in the...

Configuring FRF12 Frame Relay Fragmentation

This topic describes the Cisco IOS commands that are required to configure FRF. 12. This topic describes the Cisco IOS commands that are required to configure FRF. 12. FRF. 12 fragmentation is configured within the Frame Relay map class. The frame-relay fragment command sets the maximum fragment size in bytes. On an interface, the frame-relay class command applies the map class to the interface, subinterface, or a DLCI. FRF. 12 requires FRTS to be enabled. The figure shows a configuration...

Configuring LANBased Classification and Marking

This topic describes the Cisco IOS commands that are required to configure LAN-based classification and marking. The figure shows some of the QoS configuration commands that are necessary for Catalyst 2950 switches. The defaults for its interfaces are as follows Pass-through mode is disabled. Trusted boundary is disabled. mls qos trust cos pass-through dscp device cisco-phone dscp

Configuring MLP with Interleaving

This topic describes the Cisco IOS commands required to configure MLP with interleaving. To configure MLP with interleaving, you must perform these configuration steps Step 17 Enable MLP on a PPP interface. Step 18 On the multilink interface, enable interleaving within MLP. Step 19 In the multilink interface configuration, specify the maximum fragment size by specifying the maximum desired serialization delay in ms. The ppp multilink command enables MLP on a PPP interface. The ppp multilink...

Configuring NBAR for Stateful Protocols

This topic describes the Cisco IOS commands that are required to configure NBAR to recognize TCP and UDP stateful protocols. NBAR has enhanced classification capabilities for HTTP. It can classify packets belonging to HTTP flows based on the following The URL portion after the host name, which appears in the GET request of the HTTP session The host name specified in the GET request The MIME type specifying the type of object in the HTTP response Note The match protocol command has been...

Configuring NBAR for Stateful Protocols Example

On the input interface, three class maps have been created voice-in, videoconferencing-in, and interactive-in. The voice-in class map will match the RTP audio protocol the videoconferencing-in class map will match the RTP video protocol and the interactive-in class map will match the Citrix protocol. The policy map class mark will then do the following If the packet matches the voice-in class map, the packet differentiated services code point (DSCP) field will be set to Expedited Forwarding...

Configuring NBAR for Static Protocols Example

HTTP is a static protocol using a well-known port number 80. However, other port numbers may also be in use. The ip nbar port-map command will inform the router that other ports are also used for HTTP. HTTP is a static protocol using a well-known port number 80. However, other port numbers may also be in use. The ip nbar port-map command will inform the router that other ports are also used for HTTP. HTTP is often used on other port numbers. The example shows the usage of the ip nbar portmap...

Configuring QoS Preclassify

Enables the QoS preclassification feature. This command is restricted to tunnel interfaces, virtual templates, and crypto maps. Introduced for Cisco 2600 and 3600 in Cisco IOS Release 12.2(2)T. GRE and IPIP Tunnels router(config) interface tunnelO router(config-if) qos pre-classify router(config) interface virtual-templatel router(config-if) qos pre-classify router(config) crypto map secured-partner router(config-crypto-map) qos pre-classify The qos pre-classify Cisco IOS command enables the...

Configuring Voice Adaptation with Endto End Fragmentation on the Interface

Interface serialO encapsulation frame-relay frame-relay fragmentation voice-adaptive deactivation 30 (FR-VATS + FRF.12) frame-relay interface-dlci 100 class voice-adaptive-class (Binds voice_adaptive_class to the DLCI) frame-relay fragment 80 end-to-end (FRF.12 fragment for 384 kbps PVC on the interface) class-map match-all voice match access-group 102 class-map match-all data match access-group 101 policy-map VOICE-TRAFFIC-SHAPING class voice priority 10 (Strict Priority) class data bandwidth...

Configuring Voice Adaptation with Endtoend Fragmentation Through a Map Class

Interface serial0 encapsulation frame-relay frame-relay fragmentation voice-adaptive deactivation 30 (FR-VATS + FRF.12) frame-relay interface-dlci 100 class voice-adaptive-class (Binds voice_adaptive_class to the DLCI) map-class frame-relay voice-adaptive-class frame-relay fragment 80 (FRF.12 fragment for 384 kbps PVC through the map-Class) service-policy output TRAFFIC-SHAPE (Embeds FR-VATS Feature to map-class) class-map match-all voice match access-group 102 class-map match-all data match...

Configuring WRR on Catalyst 2950 Switches

This topic describes the commands required to configure WRR on the Catalyst 2950 switch. Use the wrr-queue bandwidth global configuration command to assign WRR weights to the four CoS priority queues on the Catalyst 2950 switch. Use the no form of this command to disable the WRR scheduler and enable the strict priority scheduler. For weight 1, weight 2, and weight 3, the range is 1 to 255. The range for weight 4 is 0 to 255. Queues 1, 2, and 3 can be configured for WRR scheduling and queue 4...

Congestion and Queuing

Congestion can occur at any point in the network where there are points of speed mismatches, aggregation, or confluence. Congestion can occur at any point in the network where there are points of speed mismatches, aggregation, or confluence. Queuing manages congestion to provide bandwidth and delay guarantees. Congestion can occur anywhere within a network where speed mismatches (for example, a GigabitEthernet link feeding a FastEthernet link), aggregation (for example, multiple...

Congestion Avoidance

Congestion avoidance may randomly drop packets from selected queues when previously defined limits are reached. Congestion avoidance may randomly drop packets from selected queues when previously defined limits are reached. By dropping packets early, congestion avoidance helps prevent bottlenecks downstream in the network. Congestion avoidance technologies include random early detection and weighted random early detection. Congestion-avoidance mechanisms monitor network traffic loads in an...

Congestion on Software Interfaces

This topic describes how congestion occurs on software interfaces. This topic describes how congestion occurs on software interfaces. Subinterfaces and software interfaces do not have their own separate transmit (Tx) ring therefore, no congestion can occur. These interface types include dialers, tunnels, and Frame Relay subinterfaces, and will only congest when their main hardware interface Tx ring congests. The Tx ring state is an indication of congestion for software interfaces. Software...

Converged Networks Quality Issues

Telephone Call I cannot understand you your voice is breaking up. Telephone Call I cannot understand you your voice is breaking up. Teleconferencing The picture is very jerky. Voice not synchronized. Brokerage House I needed that information two hours ago Where is it Call Center Please hold while my screen refreshes. With inadequate preparation of the network, voice transmission is choppy or unintelligible. Gaps in speech are particularly troublesome where pieces of speech are interspersed with...

Converged Networks Quality Issues Cont

Lack of bandwidth Multiple flows compete for a limited amount of bandwidth. End-to-end delay (fixed and variable) Packets have to traverse many network devices and links that add up to the overall delay. Variation of delay (jitter) Sometimes there is a lot of other traffic, which results in more delay. Packet loss Packets may have to be dropped when a link is congested. The four big problems facing converged enterprise networks are as follows Bandwidth capacity Large graphics files, multimedia...

Converged traffic characteristics

Constant small-packet voice flow competes with bursty data flow Critical traffic must get priority Voice and video are time-sensitive Brief outages not acceptable Order Entry, Finance, Manufacturing, HR, Training, Other Order Entry, Finance, Manufacturing, HR, Training, Other The figure illustrates a converged network in which voice, video, and data traffic use the same network facilities. Merging these different traffic streams with dramatically differing requirements can lead to a number of...

CoStoDSCP Default Mapping

To define the ingress CoS-to-DSCP mapping for trusted interfaces, use the mls qos map cos-dscp command. The CoS-to-DSCP map is used to map the CoS of packets arriving on trusted interfaces (or flows) to a DSCP where the trust type is trust-cos. This map is a table of eight CoS values (0 through 7) and their corresponding DSCP values. Use the no form of this command to remove a prior entry.

Course Goal

To identify, describe, and correctly implement the appropriate QoS mechanisms required to create an effective administrative policy providing QoS. Implementing Cisco Quality of Service (QOS) Upon completing this course, you will be able to meet these objectives Explain the need to implement QoS and methods for implementing and managing QoS Identify and describe different models used for ensuring QoS in a network and explain key QoS mechanisms used to implement the models Explain the use of MQC...

Data Plane Policing

This topic describes how to use policing and the scavenger class to protect the data plane. Data Plane policing is the actual policing of data traffic. Understanding what is a normal profile behavior for users and servers and what is not is key in setting up policers to remark and drop packets. Out-of-profile behavior could be categorized by the increase in data traffic as a worm is being propagated over the enterprise network. Normal profile behavior could be what is expected from end-user...

Default CoS assignment can be altered during configuration

The default QoS settings for the Catalyst 2950 and 3550 switches are as follows The default port CoS value is 0. The CoS value of 0 is assigned to all incoming packets. The default port trust state is untrusted. If a port is connected to an IP Phone, you should change the default port configuration to trust the CoS setting from the IP Phone using the mls qos trust command. No policy maps are configured. No policers are configured. The default CoS assignments to priority queues are as follows...

Deploying Endto End QoS Cont

E2E QoS Enterprise QoS + Service Provider QoS E2E QoS Enterprise QoS + Service Provider QoS Classification Trust on IP Multiple Queues on Switch Ports Classification Trust on IP Multiple Queues on Switch Ports Multiple Queues on Switch Ports WRED within Data Queue for Congestion Avoidance Link Fragmentation and Interleaving 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...

Describe QoS SLA

Explain the typical network requirements within each functional block (campus LAN, WAN edge, service provider backbone, and branch) that makes up an end-to-end network Explain the best-practice QoS implementations and configurations within a campus LAN Explain the best-practice QoS implementations and configurations on WAN CE and PE routers Explain the best-practice QoS implementations and configurations on the service provider IP core and PE routers

Determine required response time

The first step in implementing QoS is identifying the traffic on the network and determining QoS requirements for the traffic. The next step is determining the QoS problems of users. Measure the traffic on the network during congested periods. Conduct CPU utilization assessment on each of their network devices during busy periods to determine where problems might be occurring. Next, determine the business model and goals, and obtain a list of business requirements, in order to define the number...

Diff Serv backbone is better

Two of the IP backbone design methods include a best-effort backbone with overprovisioning and a DiffServ backbone. The more traditional approach is to use a best-effort backbone with overprovisioning. However, to meet the application needs of today (VoIP, videoconferencing, e-learning, and so on), deploying a DiffServ backbone and offering different SLAs for the different traffic classes can greatly reduce the cost and improve the delay, jitter, and packet loss and meet network QoS...

Displays information about individual multilink fragments and interleaving events

The debug ppp multilink fragments command is a valuable troubleshooting tool when monitoring MLP LFI operations. This command outputs the result of every fragmentation operation, indicating whether the packets are fragmented into correct-sized fragments. Caution This command should be used with extreme caution in a production environment, because of the amount of output that is created.

Displays information about the indicated policy map including the configuration of all classes for a specified service

Router> show policy-map shape-cbwfq CIR 384000 (bps) Max. Buffers Limit 1000 (Packets) Bandwidth 256 (kbps) Max Threshold 64 (packets) The show policy-map command displays the policy-map configuration. The output represents the CBWFQ in conjunction with the class-based shaping configuration example shown earlier, in which the custl traffic class is shaped to an average rate of 384 kbps, with a default buffer limit of 1000 packets and a minimum bandwidth guarantee of 256 kbps.

Displays interface delays including the activated queuing mechanism with the summary information

Router> show interface serial 1 0 Hardware is M4T Internet address is 20.0.0.1 8 MTU 1500 bytes, BW 19 Kbit, DLY 20000 usee, rely 255 255, load 147 255 Encapsulation HDLC, ere 16, loopback not set Keepalive set (10 sec) Last input 00 00 00, output 00 00 00, output hang never Last clearing of show interface counters never Input queue 0 75 0 (size max drops) Total output drops 0 Queueing strategy weighted fair Output queue 0 1000 64 0 (size max total threshold drops) Conversations 0 4 256...

Displays the configuration of all classes configured for all service policies on the specified interface

Router show policy-map interface Serial4 1 Serial4 1 Service-policy output policy_ecn Class-map prec1 (match-all) 1000 packets, 125000 bytes 30 second offered rate 14000 bps, drop rate 5000 bps (pkts matched bytes matched) 989 123625 (depth total drops no-buffer drops) 0 455 0 exponential weight 9 explicit congestion notification The show policy-map interface command displays the configuration of all classes configured for all service policies on the specified interface. The counters displayed...

Displays the configuration of all classes for a specified service policy map or all classes for all existing policy maps

The show policy-map command can be used to verify the configuration of a policy map. The show policy-map command can be used to verify the configuration of a policy map. The show policy-map command also displays live information if the interface keyword is used. The sample output shows the parameters and statistics of the policy map that is attached to outbound traffic on interface FastEthernet0 0. This topic describes how a service policy is assigned to an interface. This topic describes how a...

Displays the interface configurations policy maps class maps and ACLs created on the basis of automatically generated

Router> show auto qos interface Serial6 0 service-policy output AutoQoS-Policy-UnTrust When the auto qos voip command is used to configure the AutoQoS VoIP feature, configurations are generated for each interface or PVC. These configurations are then used to create the interface configurations, policy maps, class maps, and ACLs. The show auto qos command can be used to verify the contents of the interface configurations, policy maps, class maps, and ACLs. The show auto qos interface command...

Displays the mapping of the CoS priority queues

Switch> show wrr-queue cos-map CoS Value 0 1 2 3 4 5 6 7 The show wrr-queue bandwidth command is used to display the WRR bandwidth allocation for the four CoS priority queues. The show wrr-queue cos-map command is used to display the mapping of the CoS priority queues. Use the show mls qos interface command to display QoS information at the interface level. Although it will be visible in command-line interface (CLI) help strings, the policers keyword is available only when the Catalyst 2950...

Do you want three to seven day ground delivery

DiffServ was designed to overcome the limitations of both the Best-Effort and IntServ models. DiffServ can provide an almost guaranteed QoS, while still being cost-effective and scalable. DiffServ is similar to a concept known as soft QoS. With soft QoS, QoS mechanisms are used without prior signaling. In addition, QoS characteristics (bandwidth and delay, for example), are managed on a hop-by-hop basis by policies that are established independently at each intermediate device in the network....

Does not display any user changes to the configuration that might be in effect

Initial configuration applied by AutoQoS mls qos map cos-dscp 0 8 16 26 32 46 48 56 To display the initial AutoQoS configuration, use the show auto qos interface interface-id privileged EXEC command. To display any user changes to that configuration, use the show running-config privileged EXEC command. You can compare the show auto qos and the show running-config command output to identify the user-defined QoS settings. show mls qos interface interface-id vlan vlan-id buffers policers queueing...

DSCP 4863 to queue

At the distribution switch, configure the trust boundary to trust the DSCP or CoS marking from the core and access layer switches. For Layer 2-to-Layer 3 and Layer 3-to-Layer 2 QoS mappings, the Catalyst 4500 has default CoS-to-DSCP and DSCP-to-CoS mappings. However, you can manually configure these default mappings to override the default mappings. The Catalyst 4500 has these CoS-to-DSCP and DSCP-to-CoS mappings You can also implement class-based policing to rate-limit certain traffic classes....

DSCP The first six bits of the Diff Serv field used to select a PHB forwarding and queuing method

DiffServ uses the DiffServ field in the IP header to mark packets according to their classification into behavior aggregates (BAs). The DiffServ field occupies the same eight bits of the IP header that were previously used for the ToS byte. The following three Internet Engineering Task Force (IETF) standards describe the purpose of those eight bits RFC 791 includes specification of the ToS field, where the high-order three bits are used for IP Precedence. The other bits are used for delay,...

DSCP value 101110 looks like IP Precedence 5 to nonDiff Servcompliant devices

- Bits 5 to 7 101 5 (Same three bits used for IP Precedence) - Bits 3 to 4 11 drop probability high The EF PHB is identified based on the following The EF PHB ensures a minimum departure rate. The EF PHB provides the lowest possible delay to delay-sensitive applications. The EF PHB guarantees bandwidth. The EF PHB prevents starvation of the application if there are multiple applications using EF PHB. The EF PHB polices bandwidth when congestion occurs. The EF PHB prevents starvation of other...

DSCP value range aaaddO

- Where aaa is a binary value of the class - Where dd is drop probability The AF PHB is identified based on the following The AF PHB guarantees a certain amount of bandwidth to an AF class. The AF PHB allows access to extra bandwidth, if available. Packets requiring AF PHB should be marked with DSCP value aaaddO where aaa is the number of the class and dd is the drop probability. There are four standard-defined AF classes. Each class should be treated independently and should have allocated...

Each segment has 46 bytes of overhead Ppp Ip Udp and RTP headers

The example shows the benefits of RTP header compression on slow links. A 64-kbps link is used to transport VoIP using PPP as the Layer 2 framing protocol. For the case study application (voice, using the G.729 audio compression codec), the payload size is 20 bytes. Because PPP has 6 bytes of frame header, the total header overhead is 6 + 20 + 8 + 12 46 bytes, including the PPP, IP, UDP, and RTP headers. Class-Based RTP Header Compression Example (Cont.) Overhead 46 (46 + 20) 70 Overhead 10 (10...

ECN Field Defined

This topic describes the characteristics of the ECN field in IP. The Addition of Explicit Congestion Notification to IP (RFC 3168) redefines the DiffServ field (formerly the type of service ToS byte) to contain an ECN-specific field. The ECN field consists of the last two low-order bits of the DiffServ field, and consists of the ECN-capable transport (ECT) bit and the congestion experienced (CE) bit. The ECT bit and the CE bit can be used to make four ECN field combinations 00, 01, 10, and 11....

Enabling RSVP

Router(config-if)ip rsvp bandwidth interface-kbps single-flow-kbps Disabling Reserving Interface Resources Router(config-if)ip rsvp resource-provider none Router(config-if)ip rsvp data-packet classification none The figure shows the router interface commands used to enable and disable RSVP on an interface. The first bulleted item shows the command for enabling RSVP on an interface, and the arguments under this command are to either accept the default maximum data flow, which is 75 of the line...

Enterprise Network with Traditional Layer 2 Service

Provider sells the customer a Layer 2 service Point-to-point SLA from the provider Enterprise WAN likely to get congested QoS required for voice, video, data integration Service provider is not involved in QoS Provider sells the customer a Layer 2 service Point-to-point SLA from the provider Enterprise WAN likely to get congested QoS required for voice, video, data integration Service provider is not involved in QoS This figure illustrates a service provider providing only Layer 2 services to...

Enterprise to Service Provider QoS Class Mapping Example

The figure illustrates how the different enterprise traffic classes can be mapped into the four traffic classes offered by a service provider. In the example, there is no streaming video traffic. The following four traffic classes are offered by the service provider Controlled Latency A traffic class for all real-time traffic. The controlled latency class admits packets marked with CS5 and Expedited Forwarding (EF). Controlled Load 1 A traffic class for all highly bursty traffic. The controlled...

Example Calculating the Bandwidth Requirement for a 384kbps Videoconference Stream

This example shows how to calculate the bandwidth requirement for a 384-kbps videoconferencing stream 384 kbps + (20 x 384 kbps) 384 kbps + 76.8 kbps 384 kbps + (20 x 384 kbps) 384 kbps + 76.8 kbps Because bandwidth requirements vary greatly from application to application, and even between versions of the same applications, it is not possible to provide a blanket rule for provisioning data bandwidth. Traffic analysis and lab testing are required to ascertain bandwidth requirements for data...

Example Cisco IOS QoS Tools Summary

In this course, you have learned about the various QoS tools available within Cisco IOS software. The following list groups some of these tools into the proper categories QoS Policy Propagation on Border Gateway Protocol (BGP), or QPPB Voice, Video, and Data QoS Requirements This topic describes the QoS requirements of the different application types.

Example Class Map Configuration

This example shows a traffic class configured with the class-map match-all command Router(config) class-map match-all ciscol Router(config-cmap) match protocol ip Router(config-cmap) match qos-group 4 Router(config-cmap) match access-group 101 If a packet arrives on a router with traffic class called cisco1 configured on the interface, the packet is evaluated to determine if it matches the IP protocol, QoS group 4, and access group 101. If all three of these match criteria are met, the packet...

Example Class Based Shaping with CBWFQ

Class-based shaping can be used in combination with CBWFQ. The shape rate provides a maximum rate limit for the traffic class, while the bandwidth statement within CBWFQ provides a minimum bandwidth guarantee. In the example, the cust1 traffic class is shaped to an average rate of 384 kbps, and is guaranteed a minimum of 256 kbps by the CBWFQ bandwidth statement. Because the Bc and Be are not specified, they will be automatically calculated by the Cisco IOS software. Example Class-Based Shaping...

Example Configuring MQC

Consider this example of configuring MQC on a network with voice telephony Step 1 Classify traffic as voice, high priority, low priority, and browser in a class map. Step 2 Build a single policy map that defines three different traffic policies (different bandwidth and delay requirements for each traffic class) NoDelay, BestService, and Whenever, and assign the already defined classes of traffic to the policies. Voice is assigned to NoDelay. High-priority traffic is assigned to BestService....

Example Configuring the AutoQoS Enterprise Feature on a High Speed Serial Interface

In the example, the AutoQoS Enterprise feature is configured on the high-speed serial interface s1 1 Router> enable Router configure terminal Router(config) interface s1 1 Router(config-if) bandwidth 1540 Router(config-if) ip address 10.10.100.1 255.255.255.0 Router(config-if) auto discovery qos Router(config-if) auto qos Router(config-if) exit This topic describes how to use Cisco IOS commands to examine and monitor a network configuration after AutoQoS has been configured. When the AutoQoS...

Example Configuring the AutoQoS VoIP Feature on a High Speed Serial Interface

In the example, the AutoQoS VoIP feature is configured on the high-speed serial interface s1 2 Router> enable Router configure terminal Router(config) interface s1 2 Router(config-if) bandwidth 1540 Router(config-if) auto qos voip Router(config-if) exit Global configuration command. All the global QoS settings are applied to all ports in the switch. Prompt displays the CLI for the port-based automatic QoS commands currently supported. Console> (enable)set qos autoqos QoS is enabled All...

Example Defining QoS Service Classes

A network administrator wants to apply QoS to the corporate network to better control bandwidth allocation of different network applications. Before QoS can be applied, an administrative QoS policy is first devised as follows Voice traffic is to be given a strict priority over all other traffic types. Business applications (FTP, TN3270, and Oracle) should be given priority over web traffic and have a guaranteed bandwidth of 20 percent. Web traffic should consume no more than 30 percent of any...

Example G711 Voice Bearer Bandwidth Requirement Calculation

This example shows how to calculate the VoIP bearer bandwidth requirement for a single VoIP call using a G.711 codec (Layer 2 overhead not included) Sampling Rate 20 msec per sample 50 samples per second Bandwidth (bytes sec) without Layer 2 overhead 200 bytes packet x 50 packets second 10000 bytes second Bandwidth (bits sec) without Layer 2 overhead 10000 bytes second * 8 bits byte 80000 bytes second (80 kbps) payload size + IP UDP RTP headers 160 bytes + 20 bytes + 8 bytes + 12 bytes 200...

Example Hierarchical Policy Maps

In the example diagram, a child policy-map QueueAll is created, which guarantees bandwidth of 1 Mbps to HTTP traffic. Hierarchical (Nested) Policy Maps Example Shape all traffic on FastEthernet to 2 Mbps. Out of the 2 Mbps, guarantee 1 Mbps to HTTP traffic. The QueueAll policy map is then nested within a parent policy map named ShapeAll. Finally, the parent policy map ShapeAll is applied to the FastEthernet interface. Traffic out of the FastEthernet interface will first be shaped to 2 Mbps and...