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 at the end of this module.
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.
Information About IPv6 QoS: MQC Packet Classification
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:
applications in your network need QoS.
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
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
matchdscp. If you want to treat them separately,
add match criteria such as
matchprotocolipv6 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 in IPv6
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.
How to Configure IPv6 QoS: MQC Packet Classification
matchcos 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.
Using the Match Criteria to Manage IPv6 Traffic Flows
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.
Matches the precedence value. The precedence applies to both IPv4 and IPv6 packets.
Specifies the name of an IPv6 access list against whose contents packets are checked to determine if they belong to the traffic class.
Identifies a specific IP DSCP value as a match criterion.
Confirming the Service Policy
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.
The following example shows how to configure the service policy called priority50 and attach service policy priority50 to an interface. In this example, the
matchdscp 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.
match ip dscp 15
service-policy input priority55
To match on IPv6 packets only, use the
matchdscp command without the
ip keyword preceded by the
matchprotocol command. Ensure that the class map has the
match-all attribute (which is the default).
match protocol ipv6
match dscp 15
To match packets on both IPv4 and IPv6 protocols, use the
match dscp 15
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Feature Information for IPv6 QoS: MQC Packet Classification
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.
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Table 1 Feature Information for IPv6 QoS: MQC Packet Classification
IPv6 QoS: MQC Packet Classification
Cisco IOS XE Release 2.1
The modular QoS CLI allows you to define traffic classes, create and configure traffic policies, and then attach those traffic policies to interfaces.
The following commands were introduced or modified:
match access-group name,