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Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and 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 table.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
IPv6 packets are forwarded by paths that are different from those for IPv4. QoS features supported for IPv6 environments include packet classification, queueing, traffic shaping, weighted random early detection (WRED), class-based packet marking, and policing of IPv6 packets. These features are available at both the process switching and Cisco Express Forwarding switching paths of IPv6.
All of the QoS features available for IPv6 environments are managed from the modular QoS command-line interface (MQC). The MQC allows you to define traffic classes, create and configure traffic policies (policy maps), and then attach those traffic policies to interfaces.
To implement QoS in networks running IPv6, follow the same steps that you would follow to implement QoS in networks running only IPv4. At a very high level, the basic steps for implementing QoS are as follows:
Know which applications in your network need QoS.
Understand the characteristics of the applications so that you can make decisions about which QoS features would be appropriate.
Know your network topology so that you know how link layer header sizes are affected by changes and forwarding.
Create classes based on the criteria you establish for your network. In particular, if the same network is also carrying IPv4 traffic along with IPv6, decide if you want to treat both of them the same way or treat them separately and specify match criteria accordingly. If you want to treat them the same, use match statements such as match precedence, match dscp, set precedence, and set dscp. If you want to treat them separately, add match criteria such as match protocol ip and match protocol ipv6 in a match-all class map.
Create a policy to mark each class.
Work from the edge toward the core in applying QoS features.
Build the policy to treat the traffic.
Apply the policy.
Packet classification is available with both process and Cisco Express Forwarding switching path. Classification can be based on IPv6 precedence, differentiated services control point (DSCP), and other IPv6 protocol-specific values that can be specified in IPv6 access lists in addition to other non-IPv6 protocol specific values such as COS, packet length, and QOS group. Once you determine which applications need QoS, you can create classes based on the characteristics of the applications. You can use a variety of match criteria to classify traffic. You can combine various match criteria to segregate, isolate, and differentiate traffic.
The enhancements to the modular QoS CLI (MQC) allow you to create matches on precedence, DSCP, and IPv6 access group values in both IPv4 and IPv6 packets. The match command allows matches to be made on DSCP values and precedence for both IPv4 and IPv6 packets.
The set cos and match cos commands for 802.1Q (dot1Q) interfaces are supported only for packets that are switched by Cisco Express Forwarding. Packets that are process-switched, such as device-generated packets, are not marked when these options are used.
You can use multiple match statements. Depending on the type of class, you can specify whether to match all classes or any of the classes.
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enable
2.
configure
terminal
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class-map
{class-name|
class-default}
Ensure that the traffic flow matches the input or output parameter of the policy. For example, downloading a file from an FTP server generates congestion in the receive direction because the server sends large MTU-sized frames, and the client PC returns small acknowledgments (ACKs).
Before you begin this task, simulate congestion with an extended ping using a large ping size and a large number of pings. Also, try downloading a large file from an FTP server. The file constitutes "disturbing" data and fills the interface bandwidth.
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enable
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configure
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interface
type
number
multipoint
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point-to-point
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ip
address
ip-address
mask
[secondary]
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pvc
[name]
vpi
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vci [ces |
ilmi |
qsaal |
smds]
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tx-ring-limit
ring-limit
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service-policy
{input |
output}
policy-map-name
The following example shows how to configure the service policy called priority50 and attach service policy priority50 to an interface. In this example, the match dscp command includes the optional ip keyword, meaning that the match is for IPv4 packets only. The class map called ipdscp15 will evaluate all packets entering interface GigabitEthernet 1/0/0. If the packet is an IPv4 packet and has a DSCP value of 15, the packet will be treated as priority traffic and will be allocated with bandwidth of 50 kbps.
Router(config)# class-map ipdscp15 Router(config-cmap)# match ip dscp 15 Router(config)# exit Router(config)# policy-map priority50 Router(config-pmap)# class ipdscp15 Router(config-pmap-c)# priority 50 Router(config-pmap-c)# exit Router(config-pmap)# exit Router(config)# interface gigabitethernet1/0/0 Router(config-if)# service-policy input priority55
To match on IPv6 packets only, use the match dscp command without the ip keyword preceded by the match protocol command. Ensure that the class map has the match-all attribute (which is the default).
Router(config)# class-map ipdscp15 Router(config-cmap)# match protocol ipv6 Router(config-cmap)# match dscp 15 Router(config)# exit
To match packets on both IPv4 and IPv6 protocols, use the match dscp command:
Router(config)# class-map ipdscp15 Router(config-cmap)# match dscp 15
Related Topic |
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IPv6 addressing and connectivity |
IPv6 Configuration Guide |
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Cisco IOS commands |
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IPv6 commands |
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Cisco IOS IPv6 features |
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Classifying Network Traffic |
“Classifying Network Traffic” module |
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RFCs for IPv6 |
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MIB |
MIBs Link |
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To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
Description |
Link |
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The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
The following table provides release information about the feature or features described in this module. This table 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.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
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Feature Name |
Releases |
Feature Information |
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IPv6 QoS: MQC Packet Classification |
Cisco IOS XE Release 3.13.0S |
This feature was introduced on the Cisco ASR 920 Series Aggregation Services Router (ASR-920-12CZ-A, ASR-920-12CZ-D, ASR-920-4SZ-A, ASR-920-4SZ-D). |
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