QOS Implementing

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...

In Best Effort networks propagation delay is fixed processing and queuing delays are unpredictable

The figure illustrates the impact that a network has on the end-to-end delay of packets going from one end of the network to the other. Each hop in the network adds to the overall delay because of these factors Propagation delay is caused by the speed of light traveling in the media for example, the speed of light traveling in fiber optics or copper media. Serialization delay is the time it takes to clock all the bits in a packet onto the wire. This is a fixed value that is a function of the...

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...

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...

Traffic exceeding the specified bandwidth is dropped if congestion exists otherwise policy is not used

When you specify the priority command for a class, it takes a bandwidth argument that gives maximum bandwidth in kbps. You use this parameter to specify the maximum amount of bandwidth allocated for packets belonging to the class configured with the priority command. The bandwidth parameter both guarantees bandwidth to the priority class and restrains the flow of packets from the priority class. priority bandwidth-kbps percent percentage burst priority bandwidth-kbps percent percentage burst...

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...

Managing Interface Congestion with Tail Drop

Router interfaces experience congestion when the output queue is full - Additional incoming packets are tail-dropped - Dropped packets may cause significant application performance degradation - Tail drop has significant drawbacks Router interfaces experience congestion when the output queue is full - Additional incoming packets are tail-dropped - Dropped packets may cause significant application performance degradation - Tail drop has significant drawbacks When an interface on a router cannot...

Life of a High Priority VoIP Packet

As it begins its life in the IP Phone, the VoIP packet is immediately marked with both of the following Layer 2 802.1Q CoS 5 (highest priority in an Ethernet LAN) Layer 3 DSCP EF (highest priority in an IP network) Note The IEEE 802.1Q standard is an IEEE specification for implementing VLANs in Layer 2 switched networks. IEEE 802.1Q and its use in QoS will be discussed further in the Classification and Marking module in this course. With the frame marked at class of service (CoS) 5 and...

Life of a Low Priority FTP Packet

The low-priority FTP packet begins life as a very low-priority CoS 0, DSCP 0. Note The FTP packet is using TCP rather than UDP (which was used by the voice packet). All traffic arriving from the workstation attached to the IP Phone is set to be untrusted. As a result, the IP Phone will not accept any CoS marking done by the workstation and will remark the CoS to 0. This ensures that the voice traffic generated by the IP Phone will always receive priority treatment over any traffic generated by...

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 Cisco Catalyst 2950 series switches offer superior and highly granular QoS based on Layer 2 through Layer 4 information to ensure that network traffic is classified and prioritized, and that congestion is avoided in the best possible manner. Cisco Catalyst 2950 series switches...

Trust CoS pass through DSCP

Incoming CoS > cos-dscp map > internal dscp > dscp-cos map > egress queue Example QoS Mechanisms on the Catalyst 2950 Switch The example in the illustration provides a block diagram of the QoS mechanisms on the Catalyst 2950 switch. QoS ACLs using Layer 2, 3, and 4 access control parameters - Source destination MAC address, 16-bit Ethertype, source destination IP address, TCP UDP source or destination port number QoS ACLs using Layer 2, 3, and 4 access control parameters - Source...

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...

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...

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...

Packet Loss

This topic describes how packet loss can adversely impact QoS in a network and describes ways to manage packet loss so that QoS is not affected. Tail drops occur when the output queue is full. These are common drops, which happen when a link is congested. Tail drops occur when the output queue is full. These are common drops, which happen when a link is congested. Many other types of drops exist, usually the result of router congestion, that are uncommon and may require a hardware upgrade...

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...

CDP must be enabled for AutoQoS to function properly

To configure the QoS settings and the trusted boundary feature on the Cisco IP Phone, CDP version 2 or later must be enabled on the port. If the trusted boundary feature is enabled, a syslog warning message displays if CDP is not enabled or if CDP is running version 1. CDP needs to be enabled only for the ciscoipphone QoS configuration CDP does not affect the other components of the automatic QoS features. When the ciscoipphone keyword with the port-specific automatic QoS feature is used, a...

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...

Classification and Marking at the Data Link Layer Ethernet 8021Q Class of Service

Three bits used for CoS (802.1 P user priority) Three bits used for CoS (802.1 P user priority) 802.1P user priority field, also called CoS Focuses on support for QoS over LANs and 802.1Q ports Preserved through the LAN, not end to end 802.1P user priority field, also called CoS Focuses on support for QoS over LANs and 802.1Q ports Preserved through the LAN, not end to end The 802.1Q standard is an IEEE specification for implementing VLANs in Layer 2 switched networks. The 802.1Q specification...

Configuring NBAR for Stateful Protocols Cont

Match protocol rtp audio video payload-type payload-string Stateful mechanism to identify real-time audio and video traffic Differentiate on the basis of audio and video codecs The match protocol rtp command has these options - audio Match by payload-type values 0 to 23, reserved for audio traffic - video Match by payload-type values 24 to 33, reserved for video traffic - payload-type Specifies matching by a specific payload-type value, providing more granularity than the audio or video options...

QoS Trust Boundary in the LAN Classify and Mark Where

Personal Computer Frames are typically unmarked (CoS 0) unless NIC is 802.1P- or 802.1Q-capable If marked, IP Phone can (and by default does) reclassify CoS but not DSCP IP Phone Marks voice as Layer 2 CoS (default) or Layer 3 ToS or DSCP Reclassifies incoming PC data frames Access Layer Based on switch capabilities Accept or remap here Distribution Layer Example Catalyst 6000 Marks traffic Accepts CoS ToS Remaps CoS to ToS or DSCP Cisco QoS model assumes that the CoS carried in a frame may or...

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...

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...

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...

Example LLQ Example on the Enterprise WAN Edge Router

Priority percent 18 class VIDEO-CONF priority percent 15 class STREAM-VIDEO bandwidth percent 10 match ip dscp cs6 class-map match-all VOICE match ip dscp ef class-map match-all VIDEO-CONF match ip dscp af41 class-map match-all STREAM-VIDEO match ip dscp cs4 class-map match-all MISSION-CRIT match ip dscp 25 class-map match-any VOICE-CONTROL match ip dscp cs3 match ip dscp af31 class-map match-all TRANSACT match ip dscp af21 class-map match-all NETWORK-MGMT match ip dscp cs2 class-map match-all...

Using QoS Policies on VPN Interfaces

Tunnel interfaces support many of the same QoS features as physical interfaces. In VPN environments, a QoS service policy can be applied to the tunnel interface or to the underlying physical interface. The decision about whether to configure the qos pre-classify command depends on which header is used for classification. Classification defines the process of matching one or more fields in a packet header in Layer 2, 3, or 4, and then placing that packet in a group or class of traffic. Using...

CBWFQ Architecture 75 Percent Rule

- 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...

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...

Methods for Implementing QoS Policy

This topic describes four different methods for implementing and managing a QoS policy. Just a few years ago, the only way to implement QoS in a network was by using the command-line interface (CLI) to individually configure QoS policies at each interface. This was a time-consuming, tiresome, and error-prone task that involved cutting and pasting configurations from one interface to another. Cisco introduced the MQC in order to simplify QoS configuration by making configurations modular. Using...

Make sure the new configurations still conform to the design and implementation from the previous example

The same service policy will be configured in this example. In this case, however, DSCP-based classes of service are used. Remember that the DiffServ model itself provides defined traffic classes and their associated PHB. DiffServ-based classification is used in this example as follows Mission-critical class Marked using DSCP AF class 2, and should get 30 percent of an interface bandwidth Bulk class Marked using DSCP AF class 1, and should get 20 percent of the interface bandwidth Best-effort...

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...

Weighted Round Robin

WRR overcomes the problem of having PQ starving out the lower priority queues. WRR scheduling prevents queues with a lower weight from being completely starved during periods of heavy high-priority traffic. Different weights are assigned to each queue. For example, in one scheduling round, the WRR scheduler will transmit - Three frames from a queue assigned weight 3 - Four frames from a queue assigned weight 4 WRR with an expedite queue When WRR is configured on a Catalyst 2950, the option...

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...

Differentiates probability of timely forwarding xyz000 abc000 if xyz abc

- If a packet has DSCP 011000, it has a greater probability of timely forwarding than a packet with DSCP 001000. The meaning of the eight bits in the DiffServ field of the IP packet has changed over time to meet the expanding requirements of IP networks. Originally, the field was referred to as the ToS field and the first three bits of the field (bits 7 to 5) defined a packet IP Precedence value. A packet could be assigned one of six priorities based on the value of the IP Precedence value...

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...

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...

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...

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...

Overview Wmg

Because the hardware transmit queue (TxQ) is a FIFO queue, having a large packet such as an FTP packet in front of a small packet like a VoIP packet can cause excessive delay for the VoIP packet. Link fragmentation and interleaving (LFI) allows the large packets to be fragmented into smaller fragments, and then the small unfragmented packets are interleaved in between the fragments. LFI reduces the delay and jitter of small packets such as VoIP packets over a WAN link. This lesson describes the...

Hardware Queue TxQ Size

Routers determine the length of the hardware queue based on the configured bandwidth of the interface. The length of the hardware queue can be adjusted with the tx-ring-limit command. Reducing the size of the transmit ring has two benefits - It reduces the maximum amount of time that packets wait in the FIFO queue before being transmitted. - It accelerates the use of QoS in the Cisco IOS software. Improper tuning of the hardware queue may produce undesirable results - Long TxQ may result in...

Service Provider SLA Example

The actual SLA offered by service providers may vary. The figure shows an example of a typical QoS SLA from an IP service provider. In this example, the service provider offers three service classes to the customer controlled latency, controlled load, an d best effort. The SLA guarantees in this example include the following For the controlled latency class A one-way delay of 40 ms that is guaranteed 90 percent of the time A jitter of 2 ms that is guaranteed 90 percent...

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...

QoS Baseline Classification Summary

The figure illustrates a QoS baseline recommendation for traffic classification and markings. In this example, the enterprise traffic is classified into 11 traffic classes including the following Five data classes (mission-critical, transactional, bulk, scavenger, best effort) One class for network management traffic One class for routing protocol traffic One class for voice traffic One separate class for voice call-signaling traffic One class for videoconferencing traffic One class for...

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 Traffic Requirements Videoconferencing

Minimum priority bandwidth guarantee required is - For example, a 384-kbps stream would require 460 kbps of bandwidth Videoconferencing has the same latency, jitter, and packet-loss requirements as voice, but the traffic patterns of videoconferencing are radically different from voice. For example, videoconferencing traffic has varying packet sizes and extremely variable packet rates. Because of its bursty nature, videoconferencing has these two unique best-practice requirements in...

Monitoring MLP with Interleaving

This topic describes the Cisco IOS commands that are used to monitor MLP with interleaving. show interfaces multilink interface-number Displays MLP statistics including the number of interleaved frames router> show interfaces multilink 1 Multilink1 is up, line protocol is up Hardware is multilink group interface Internet address is 172.22.13 0.1 30 MTU 1500 bytes, BW 64 Kbit, DLY 100000 usec, reliability 255 255, txload 27 255, rxload 1 255 Encapsulation PPP, loopback not set Keepalive set...

TCP Traffic Before and After RED

This topic describes the effects of using RED on TCP traffic by comparing TCP traffic flows both before and after the application of RED. TCP synchronization prevents average link utilization close to the link bandwidth. TCP synchronization prevents average link utilization close to the link bandwidth. Tail drops cause TCP sessions to go into slow-start. The figure shows TCP throughput behavior compared to link bandwidth in a congested network scenario where the tail-drop mechanism is in use on...

The shape percent command cannot be configured for use in nested policy maps on 7500 routers or below

The shape average and shape peak commands configure average and peak shaping, respectively. The Bc and Be value in bits can be explicitly configured, or Cisco IOS software can automatically calculate their optimal value. It is not recommended that you configure the Bc and Be in order to let the Cisco IOS algorithm determine the best Bc and Be value to use. Class-based traffic shaping uses a single token bucket with a maximum token bucket size of Bc + Be. The shape percent command is often used...

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...

Policing vs Shaping

Incoming and outgoing directions Incoming and outgoing directions Out-of-profile packets are dropped Dropping causes TCP retransmits Supports packet marking or re-marking Less buffer usage (shaping requires an additional shaping queuing system) Out-of-profile packets are queued until a buffer gets full Buffering minimizes TCP retransmits Marking or re-marking not supported Shaping supports interaction with Frame Relay congestion indication Shaping queues excess traffic by holding packets...

Lower priority classes use CBWFQ

While WFQ provides a fair share of bandwidth to every flow, and provides fair scheduling of its queues, it cannot provide guaranteed bandwidth and low delay to select applications. For example, voice traffic may still compete with other aggressive flows in the WFQ queuing system because the WFQ system lacks priority scheduling for time-critical traffic classes. The LLQ feature brings strict priority queuing to CBWFQ. Strict priority queuing allows delay-sensitive data such as voice to be...

Example RCL Enterprise

In this example, the RCL enterprise network administrator used NBAR and determined that the major sources of network traffic are from the following applications Structured Query Language (SQL) The RCL senior management team has determined that only SQL and HTTP traffic are mission-critical to the company. RCL has decided to implement four traffic classes as follows A real-time traffic class for VoIP traffic all RTP traffic A mission-critical data traffic class for mission-critical traffic SQL...

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...

Modular QoS CLI

This topic describes the MQC method for implementing QoS. This topic describes the MQC method for implementing QoS. Configure policy, not raw access-list 100 permit ip any any precedence 5 access-list 100 permit ip any any dscp ef access-list 101 permit tcp any host 10.1.10.20 range 2000 2002 access-list 101 permit tcp any host 10.1.10.20 range 11000 11999 The MQC is a CLI structure that allows you to create traffic policies and then attach these policies to interfaces. A traffic policy...

QoS for Converged Networks

There are three basic steps involved in implementing QoS on a network Step 1 Identify traffic and its requirements. Study the network to determine the type of traffic running on the network and then determine the QoS requirements for the different types of traffic. Step 2 Group the traffic into classes with similar QoS requirements. In the example, four classes of traffic can be defined voice, high priority, low priority, and browser. Step 3 Define QoS policies that will meet the QoS...

Know the SLA Offered by Your SP

SLA typically includes three to five classes. Real-time traffic gets fixed bandwidth allocation. Data traffic gets variable bandwidth allocation with minimum guarantee. Additional classes not visible to customer may exist at the edge. A typical QoS SLA offered by most service providers typically includes three to five traffic classes for example, a real-time traffic class, a mission-critical data traffic class, one or two other data traffic classes, and a best-effort traffic class. The SLA 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...

Qavet1 Qavet 0998 Qt 0002

WRED does not calculate the drop probability using the current queue length, but rather uses the average queue length. The average queue length is constantly recalculated using two terms the previously calculated average queue size and the current queue size. An exponential weighting constant N influences the calculation by weighing the two terms, therefore influencing how the average queue size follows the current queue size, in this way For high values of N, the previous average becomes more...

Speed mismatches are the most typical cause of congestion Possibly persistent when going from LAN to WAN Usually

Speed mismatches are the most typical cause of congestion in a network. Speed mismatches are most common when traffic moves from a high-speed LAN environment (1000 Mbps or higher) to lower-speed WAN links (1 or 2 Mbps). Speed mismatches are also common in LAN-to-LAN environments when, for example, a 1000-Mbps link feeds into a 100-Mbps link. The most common site of congestion is at points of aggregation in a network. Typical points of aggregation occur in WANs when multiple remote sites feed...

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...