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Classifying network traffic allows you to organize traffic (that is, packets) into traffic classes or categories on the basis of whether the traffic matches specific criteria. Classifying network traffic is the foundation for enabling many quality of service (QoS) features on your network. This module contains conceptual information and the configuration tasks for classifying network traffic.
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the "Feature Information for Classifying Network Traffic" section.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
•Prerequisites for Classifying Network Traffic
•Information About Classifying Network Traffic
•How to Classify Network Traffic
•Configuration Examples for Classifying Network Traffic
•Feature Information for Classifying Network Traffic
To mark network traffic, Cisco Express Forwarding (CEF) must be configured on both the interface receiving the traffic and the interface sending the traffic.
•Purpose of Classifying Network Traffic
•Benefits of Classifying Network Traffic
•MQC and Network Traffic Classification
•Network Traffic Classification match Commands and Match Criteria
•Traffic Classification Compared with Traffic Marking
Classifying network traffic allows you to organize traffic (that is, packets) into traffic classes or categories on the basis of whether the traffic matches specific criteria. Classifying network traffic is the foundation for enabling other QoS features such as traffic shaping and traffic policing on your network.
The goal of network traffic classification is to group traffic based on user-defined criteria so that the resulting groups of network traffic can then be subjected to specific QoS treatments. The QoS treatments might include faster forwarding by intermediate routers and switches or reduced probability of the traffic being dropped due to lack of buffering resources.
Identifying and categorizing network traffic into traffic classes (that is, classifying packets) enables distinct handling for different types of traffic, effectively separating network traffic into different categories. This classification can be associated with a variety of match criteria such as the IP Precedence value, differentiated services code point (DSCP) value, class of service (CoS) value, source and destination MAC addresses, input interface, or protocol type. You classify network traffic by using class maps and policy maps with the Modular Quality of Service Command-Line Interface (MQC). For example, you can configure class maps and policy maps to classify network traffic on the basis of the QoS group, Frame Relay DLCI number, Layer 2 packet length, or other criteria that you specify.
Classifying network traffic allows you to see what kinds of traffic you have, organize the various kinds of network traffic into traffic classes, and treat some types of traffic differently than others. Identifying and organizing network traffic is the foundation for applying the appropriate QoS feature to that traffic, enabling you to allocate network resources to deliver optimal performance for different types of traffic. For example, high-priority network traffic or traffic matching specific criteria can be singled out for special handling, and thus, help to achieve peak application performance.
To configure network traffic classification, you use the Modular Quality of Service Command-Line Interface (MQC).
The MQC is a CLI structure that allows you to complete the following tasks:
•Specify the matching criteria used to define a traffic class.
•Create a traffic policy (policy map). The traffic policy defines the QoS policy actions to be taken for each traffic class.
•Apply the policy actions specified in the policy map to an interface, subinterface, or ATM permanent virtual circuit (PVC) by using the service-policy command.
Network traffic classification allows you to group or categorize traffic on the basis of whether the traffic meets one or more specific criteria. For example, network traffic with a specific IP precedence can be placed into one traffic class, while traffic with a specific DSCP value can be placed into another traffic class. The network traffic within that traffic class can be given the appropriate QoS treatment, which you can configure in a policy map later.
You specify the criteria used to classify traffic with a match command. Table 1 lists the available match commands and the corresponding match criterion.
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|
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match access group |
Access control list (ACL) number |
match any |
Any match criteria |
match class-map |
Traffic class name |
match cos |
Layer 2 class of service (CoS) value |
match destination-address mac |
MAC address |
match discard-class |
Discard class value |
match dscp |
DSCP value |
match field |
Fields defined in the protocol header description files (PHDFs) |
match fr-de |
Frame Relay discard eligibility (DE) bit setting |
match fr-dlci |
Frame Relay data-link connection identifier (DLCI) number |
match input-interface |
Input interface name |
match ip rtp |
Real-Time Transport Protocol (RTP) port |
match mpls experimental |
Multiprotocol Label Switching (MPLS) experimental (EXP) value |
match mpls experimental topmost |
MPLS EXP value in the topmost label |
match not |
Single match criterion value to use as an unsuccessful match criterion |
match packet length (class-map) |
Layer 3 packet length in the IP header |
match port-type |
Port type |
match precedence |
IP precedence values |
match protocol |
Protocol type |
match protocol (NBAR) |
Protocol type known to network-based application recognition (NBAR) |
match protocol citrix |
Citrix protocol |
match protocol fasttrack |
FastTrack peer-to-peer traffic |
match protocol gnutella |
Gnutella peer-to-peer traffic |
match protocol http |
Hypertext Transfer Protocol |
match protocol rtp |
RTP traffic |
match qos-group |
QoS group value |
match source-address mac |
Source Media Access Control (MAC) address |
match start |
Datagram header (Layer 2) or the network header (Layer 3) |
match tag (class-map) |
Tag type of class map |
match vlan (QoS) |
Layer 2 virtual local-area network (VLAN) identification number |
1 Cisco IOS match commands can vary by release and platform. For instance, as of Cisco IOS Release 12.2(31)SB2, the match vlan (QoS) command is supported on Cisco 10000 series routers only. For more information, see the command documentation for the Cisco IOS release and platform that you are using. |
Traffic classification and traffic marking are closely related and can be used together. Traffic marking can be viewed as an additional action, specified in a policy map, to be taken on a traffic class.
Traffic classification allows you to organize into traffic classes on the basis of whether the traffic matches specific criteria. For example, all traffic with a CoS value of 2 is grouped into one class, and traffic with DSCP value of 3 is grouped into another class. The match criterion is user-defined.
After the traffic is organized into traffic classes, traffic marking allows you to mark (that is, set or change) an attribute for the traffic belonging to that specific class. For instance, you may want to change the CoS value from 2 to 1, or you may want to change the DSCP value from 3 to 2.
The match criteria used by traffic classification are specified by configuring a match command in a class map. The marking action taken by traffic marking is specified by configuring a set command in a policy map. These class maps and policy maps are configured using the MQC.
Table 2 compares the features of traffic classification and traffic marking.
Note In the following task, the match fr-dlci command is shown in Step 4. The match fr-dlci command matches traffic on the basis of the Frame Relay DLCI number. The match fr-dlci command is just an example of one of the match commands that can be used. For a list of other match commands, see Table 1.
1. enable
2. configure terminal
3. class-map class-map-name [match-all | match-any]
4. match fr-dlci dlci-number
5. end
|
|
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---|---|---|
Step 1 |
enable Router> enable |
Enables privileged EXEC mode. •Enter your password if prompted. |
Step 2 |
configure terminal Router# configure terminal |
Enters global configuration mode. |
Step 3 |
class-map class-map-name [match-all | match-any] Router(config)# class-map class1 |
Creates a class map to be used for matching traffic to a specified class, and enters class-map configuration mode. •Enter the class map name. |
Step 4 |
match fr-dlci dlci-number Router(config-cmap)# match fr-dlci 500 |
(Optional) Specifies the match criteria in a class map. Note The match fr-dlci command classifies traffic on the basis of the Frame Relay DLCI number. The match fr-dlci command is just an example of one of the match commands that can be used. For a list of other match commands, see Table 1. |
Step 5 |
end Router(config-cmap)# end |
(Optional) Returns to privileged EXEC mode. |
Note In the following task, the bandwidth command is shown at Step 5. The bandwidth command configures the QoS feature class-based weighted fair queuing (CBWFQ). CBWFQ is just an example of a QoS feature that can be configured. Use the appropriate command for the QoS feature you want to use.
Note Configuring bandwidth on policies that have the class-default class is supported on physical interfaces such as Gigabit Ethernet (GigE), Serial, Mobile Location Protocol (MLP), and Multilink Frame-Relay (MFR), but it is not supported on logical interfaces such as Virtual Access Interface (VAI), Subinterface, and Frame-Relay on Virtual Circuits (FR-VC).
1. enable
2. configure terminal
3. policy-map policy-map-name
4. class {class-name | class-default}
5. bandwidth {bandwidth-kbps | remaining percent percentage | percent percentage}
6. end
7. show policy-map
or
show policy-map policy-map class class-name
8. exit
Create and configure as many policy maps as you need for your network. To create and configure additional policy maps, repeat the steps in the "Creating a Policy Map for Applying a QoS Feature to Network Traffic" section. Then attach the policy maps to the appropriate interface, following the instructions in the "Attaching the Policy Map to an Interface" section.
Note Depending on the needs of your network, policy maps can be attached to an interface, a subinterface, or an ATM PVC.
1. enable
2. configure terminal
3. interface type number [name-tag]
4. pvc [name] vpi/vci [ilmi | qsaal | smds | l2transport]
5. exit
6. service-policy {input | output} policy-map-name
7. end
8. show policy-map interface type number
9. exit
|
|
|
---|---|---|
Step 1 |
enable Router> enable |
Enables privileged EXEC mode. •Enter your password if prompted. |
Step 2 |
configure terminal Router# configure terminal |
Enters global configuration mode. |
Step 3 |
interface type number [name-tag] Router(config)# interface serial4/0 |
Configures an interface type and enters interface configuration mode. •Enter the interface type and number. |
Step 4 |
pvc [name] vpi/vci [ilmi |qsaal |smds | l2transport] Router(config-if)# pvc cisco 0/16 |
(Optional) Creates or assigns a name to an ATM PVC, specifies the encapsulation type on an ATM PVC, and enters ATM virtual circuit configuration mode. •Enter the PVC name, the ATM network virtual path identifier, and the network virtual channel identifier. Note This step is required only if you are attaching the policy map to an ATM PVC. If you are not attaching the policy map to an ATM PVC, advance to Step 6. |
Step 5 |
exit Router(config-atm-vc)# exit |
(Optional) Returns to interface configuration mode. Note This step is required only if you are attaching the policy map to an ATM PVC and you completed Step 4. If you are not attaching the policy map to an ATM PVC, advance to Step 6. |
Step 6 |
service-policy {input | output} policy-map-name Router(config-if)# service-policy input policy1 |
Attaches a policy map to an input or output interface. •Enter the policy map name. Note Policy maps can be configured on ingress or egress routers. They can also be attached in the input or output direction of an interface. The direction (input or output) and the router (ingress or egress) to which the policy map should be attached varies according your network configuration. When using the service-policy command to attach the policy map to an interface, be sure to choose the router and the interface direction that are appropriate for your network configuration. |
Step 7 |
end Router(config-if)# end |
Returns to privileged EXEC mode. |
Step 8 |
show policy-map interface type number
|
(Optional) Displays the traffic statistics of all traffic classes that are configured for all service policies either on the specified interface or subinterface or on a specific PVC on the interface. •Enter the type and number. |
Step 9 |
exit Router# exit |
(Optional) Exits privileged EXEC mode. |
Note This task is required only if you are using IPsec Virtual Private Networks (VPNs). Otherwise, this task is not necessary. For information about IPsec VPNs, see the "Configuring Security for VPNs with IPsec" module.
This task uses the qos pre-classify command to enable QoS preclassification for the packet. QoS preclassification is not supported for all fragmented packets. If a packet is fragmented, each fragment might receive different preclassifications.
1. enable
2. configure terminal
3. crypto map map-name seq-num
4. exit
5. interface type number [name-tag]
6. qos pre-classify
7. end
The following is an example of creating a class map to be used for traffic classification. In this example, a traffic class called class1 has been created. Traffic with a Frame Relay DLCI value of 500 will be put in this traffic class.
Router> enable
Router# configure terminal
Router(config)# class-map class1
Router(config-cmap)# match fr-dlci 500
Router(config-cmap)# end
Note This example uses the match fr-dlci command. The match fr-dlci command is just an example of one of the match commands that can be used. For a list of other match commands, see Table 1.
The following is an example of creating a policy map to be used for traffic classification. In this example, a policy map called policy1 has been created, and the bandwidth command has been configured for class1. The bandwidth command configures the QoS feature CBWFQ.
Router> enable
Router# configure terminal
Router(config)# policy-map policy1
Router(config-pmap)# class class1
Router(config-pmap-c)# bandwidth percent 50
Router(config-pmap-c)# end
Router#
show policy-map policy1 class class1
Router# exit
Note This example uses the bandwidth command. The bandwidth command configures the QoS feature class-based weighted fair queuing (CBWFQ). CBWFQ is just an example of a QoS feature that can be configured. Use the appropriate command for the QoS feature that you want to use.
The following is an example of attaching the policy map to an interface. In this example, the policy map called policy1 has been attached in the input direction of serial interface 4/0.
Router> enable
Router# configure terminal
Router(config)# interface serial4/0
Router(config-if)# service-policy input policy1
Router(config-if)# end
Router#
show policy-map interface serial4/0
Router# exit
The following is an example of configuring QoS when using IPsec VPNs. In this example, the crypto map command specifies the IPsec crypto map mymap 10, to which the qos pre-classify command is applied.
Router> enable
Router# configure terminal
Router(config)# crypto map mymap 10
Router(config-crypto-map)# exit
Router(config)# interface serial4/0
Router(config-if)# qos pre-classify
Router(config-if)# end
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Cisco IOS commands |
|
QoS commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples |
|
MQC |
|
Marking network traffic |
"Marking Network Traffic" module |
IPsec and VPNs |
|
NBAR |
|
CAR |
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No new or modified standards are supported, and support for existing standards has not been modified. |
— |
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No new or modified RFCs are supported, and support for existing RFCs has not been modified. |
— |
Table 3 lists the release history for this feature.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Note Table 3 lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
|
|
|
---|---|---|
Packet Classification Based on Layer 3 Packet Length |
12.2(13)T |
This feature provides the added capability of matching and classifying network traffic on the basis of the Layer3 length in the IP packet header. The Layer 3 length is the IP datagram plus the IP header. This new match criteria is in addition to the other match criteria, such as the IP precedence, differentiated services code point (DSCP) value, class of service (CoS), currently available. The following sections provide information about this feature: •Information About Classifying Network Traffic |
Packet Classification Using Frame Relay DLCI Number |
12.2(13)T |
The Packet Classification Using the Frame Relay DLCI Number feature allows customers to match and classify traffic based on the Frame Relay data-link connection identifier (DLCI) number associated with a packet. This new match criteria is in addition to the other match criteria, such as the IP Precedence, differentiated services code point (DSCP) value, class of service (CoS), currently available. The following sections provide information about this feature: •Information About Classifying Network Traffic |
Quality of Service for Virtual Private Networks |
12.2(2)T |
The QoS for VPNs feature provides a solution for making Cisco IOS QoS services operate in conjunction with tunneling and encryption on an interface. Cisco IOS software can classify packets and apply the appropriate QoS service before the data is encrypted and tunneled. The QoS for VPN feature allows users to look inside the packet so that packet classification can be done based on original port numbers and based on source and destination IP addresses. This allows the service provider to treat mission critical or multi-service traffic with higher priority across their network. The following sections provide information about this feature: •Configuring QoS When Using IPsec VPNs |
QoS: Match VLAN Note As of Cisco IOS Release 12.2(31)SB2, the QoS: Match VLAN feature is supported on Cisco 10000 series routers only. |
12.2(31)SB2 |
The QoS: Match VLAN feature allows you to classify network traffic on the basis of the Layer 2 virtual local-area network (VLAN) identification number. The following sections provide information about this feature: •Information About Classifying Network Traffic •How to Classify Network Traffic The following commands were introduced or modified by this feature: match vlan (QoS), show policy-map interface. |
Hierarchical Traffic Shaping Packet Classification Based on Layer3 Packet-Length QoS: Match VLAN |
15.0(1)S |
The Hierarchical Traffic Shaping, Packet Classification Based on Layer3 Packet-Length, QoS: Match VLAN features were integrated into the Cisco IOS Release 15.0(1)S release. |