Table Of Contents
VRF and MQC Hierarchical Shaping in PXF
This feature was introduced on the Cisco 7200 series and Cisco 7401ASR.
This feature for the Cisco 7200 series and Cisco 7401ASR was integrated into Cisco IOS Release 12.3(4)T.
This document describes the VRF and MQC Hierarchical Shaping in PXF feature in Cisco IOS Release 12.2(15)B and Cisco IOS Release 12.3(4)T. It includes the following sections:
VRF and MQC Hierarchical Shaping in PXF implements Virtual Route Forwarding (VRF) and Modular Quality of Service Command-Line Interface (MQC) hierarchical shaping in the Parallel Express Forwarding (PXF) path.
The Parallel Express Forwarding (PXF) processor enables parallel IP multipacket processing functions, working with the Route Processor (RP) to provide accelerated packet switching, as well as accelerated IP Layer 3 feature processing.
Modular Quality of Service Command-Line Interface (MQC) is designed to simplify the configuration of Quality of Service (QoS) on Cisco routers and switches by defining a common command syntax and resulting set of QoS behaviors across platforms. This model replaces the previous model of defining unique syntaxes for each QoS feature and for each platform.
The MQC contains the following three steps:
•Define a traffic class by issuing the class-map command.
•Create a traffic policy by associating the traffic class with one or more QoS features by issuing the policy-map command.
•Attach the traffic policy to the interface, subinterface, or virtual circuit (VC) by issuing the service-policy command.
For more information about MQC, refer to the Modular Quality of Service Command-Line Interface document.
Using hierarchical shaping, it is possible to configure a group of classes to which class-based weighted fair queueing (CBWFQ) is applied within that group of classes. These separate classes can then be treated as an aggregate class for the purpose of shaping amongst other classes.
For more information about other QoS features supported by PXF, see the "Quality of Service Features for Parallel Express Forwarding" section of the Release Notes for Cisco 7000 Family for Cisco IOS Release 12.2 B for Cisco IOS Release 12.2(4)B.
A VRF consists of an IP routing table, a derived Cisco Express Forwarding (CEF) table (which includes forwarding information base [FIB] and Adjacency tables), and a set of interfaces that use this forwarding table. A VRF consists of the following:
•IP routing table
•Cisco Express Forwarding (CEF) table
•Set of interfaces that use the CEF forwarding table
•Set of rules and routing protocol parameters to control the information in the routing tables
VRF PXF offloads any VRF-related routing from the Route Processor (RP) to the PXF.
This feature enables service providers to turn on VRF and MQC Hierarchical Shaping in PXF concurrently with other features in the PXF path without significant performance degradation.
•A parent policy can have only one reachable class. This class can be the default class or a named class with "match any" as its match criterion. If there is no reachable class, PXF punts packets to the RP.
•When the show policy interface command is entered, the "packets delayed" and "bytes displayed" are not displayed for all PXF shaping.
•If you configure a policy on an interface and on one of its subinterfaces, packet match statistics are displayed by the show policy interface command only for the interface, and not for the subinterface.
•The class in the parent policy is allowed only two actions, shape and, optionally, bandwidth.
Related Features and Technologies
•Per VRF AAA
•Cisco IOS Quality of Service Solutions Command Reference, Release 12.3
•Cisco IOS Quality of Service Solutions Configuration Guide Release 12.3
•"Quality of Service Features for Parallel Express Forwarding" section of the Release Notes for Cisco 7000 Family for Cisco IOS Release 12.2 B Cisco IOS Release 12.2(4)B
•Cisco 7200 series
Determining Platform Support Through Cisco Feature Navigator
Cisco IOS software is packaged in feature sets that are supported on specific platforms. To get updated information regarding platform support for this feature, access Cisco Feature Navigator. Cisco Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.
Cisco Feature Navigator is a web-based tool that enables you to determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image. You can search by feature or release. Under the release section, you can compare releases side by side to display both the features unique to each software release and the features in common.
To access Cisco Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to email@example.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions found at this URL:
Cisco Feature Navigator is updated regularly when major Cisco IOS software releases and technology releases occur. For the most current information, go to the Cisco Feature Navigator home page at the following URL:
Availability of Cisco IOS Software Images
Platform support for particular Cisco IOS software releases is dependent on the availability of the software images for those platforms. Software images for some platforms may be deferred, delayed, or changed without prior notice. For updated information about platform support and availability of software images for each Cisco IOS software release, refer to the online release notes or, if supported, Cisco Feature Navigator.
Supported Standards, MIBs, and RFCs
No new or modified standards are supported by this feature.
No new or modified MIBs are supported by this feature.
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
If Cisco MIB Locator does not support the MIB information that you need, you can also obtain a list of supported MIBs and download MIBs from the Cisco MIBs page at the following URL:
To access Cisco MIB Locator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to firstname.lastname@example.org. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions found at this URL:
No new or modified RFCs are supported by this feature.
To use the PXF processing, you must have IP CEF switching enabled.
See the following sections for the optional configuration tasks for the VRF and MQC Hierarchical Shaping in PXF feature. Each task in the list is identified as either required or optional.
•Configuring MQC Hierarchical Shaping (optional)
•Enabling the PXF Processors (optional)
•Verifying the PXF Processors (optional)
Configuring MQC Hierarchical Shaping
To configure MQC Hierarchical Shaping, enter the commands below, beginning in global configuration mode:
Enabling the PXF Processors
The PXF processors are enabled by default. If they are disabled, use the following commands in global configuration mode to enable PXF:
Router(config)# ip cef
Enables IP CEF switching on the Route Processor, if it is not currently enabled.
Router(config-if)# ip pxf
Enables IP switching in PXF.
Verifying the PXF Processors
PXF is enabled by default. The output of the show running-config command indicates that PXF is disabled by displaying "no ip pxf." If you do not see "no ip pxf," PXF is enabled.Router# show running-configBuilding configuration...Current configuration : 1227 bytes!version 12.2no service padservice timestamps debug uptimeservice timestamps log uptimeno service password-encryption!hostname Router!boot system flash disk0:c7200-js-mz.122-8.Benable password password1!ip subnet-zeroip cef!no ip pxf!!
For PXF troubleshooting tips, refer to the "PXF Troubleshooting Information" section of the "Configuration Tasks and Troubleshooting Information" chapter of the Network Processing Engine and Network Services Engine Installation and Configuration document.
Monitoring and Maintaining VRF and MQC Hierarchical Shaping in PXF
Use the following commands to monitor and maintain VRF and MQC Hierarchical Shaping in PXF:
This section provides the following configuration examples:
Configuring MQC Hierarchical Shaping Example
The following example shows how to configure hierarchical shaping:class-map match-all Voicematch access-group 2050class-map match-all Businessmatch access-group 2100class-map match-all Mgmtmatch access-group 2150class-map match-all Standardmatch access-group 2200!policy-map qosclass Businessbandwidth percent 80random-detectrandom-detect precedence 2 24 40 1police <Business rate with parameters> conform-actionset-prec-transmit 3 exceed-action set-prec-transmit 2class Standardbandwidth percent 20random-detectpolicy-map <bandwidth>-outclass class-defaultshape average <upper bandwidth>service-policy qos!interface FastEthernet1/0description unusedbandwidth 100000ip address 192.168.71.98 255.255.255.252no ip redirectsno ip proxy-arpservice-policy output <bandwidth>-outduplex full
Enabling the PXF Processors Example
The PXF processors are enabled by default. The following example shows how to enable PXF processors that have been disabled on a system on which IP CEF has also been disabled:ip cefip pxf
This section documents the new show pxf feature cef vrf command introduced by the VRF and MQC Hierarchical Shaping in PXF feature. All other commands used with this feature are documented in the Cisco IOS Release 12.3 T command reference publications.
show pxf feature cef vrf
To display the routing feature tables for VRFs on the PXF path, use the show pxf feature cef vrf command in privileged EXEC mode.
show pxf feature cef vrf vpn-name
No default behavior or values.
This command was introduced.
This command was integrated into Cisco IOS Release 12.3(4)T.
Use this command to display VRF PXF routing feature tables for CEF about a specified VPN. This command also displays information about prefix and MTRIE resource usage.
The following is sample output for the show pxf feature cef vrf command for displaying information about the VRF "vpn1":Router# show pxf feature cef vrf vpn1Shadow 8-8-4-4-8 PXF Mtrie:51 leaves, 2448 leaf bytes, 92 nodes, 56352 node bytes10 invalidations61 prefix updatesrefcounts: 3666 leaf, 3733 nodePrefix/Length Refcount Parent Address Shadow0.0.0.0/32 3 0xC0047218 0x62CAF2E18.104.22.168/16 558 0xC0047278 0x62CAF1085.0.0.0/32 3 22.214.171.124/16 0xC0047268 0x62CAEE085.0.0.1/32 3 126.96.36.199/16 0xC0047260 0x62CAEA188.8.131.52/32 3 184.108.40.206/16 0xC0047388 0x62CAEA4220.127.116.11/32 3 18.104.22.168/16 0xC0047270 0x62CAF0D822.214.171.124/16 288 0xC0047360 0x62CAEB38126.96.36.199/32 3 188.8.131.52/16 0xC0047350 0x62CAEB98184.108.40.206/32 3 0xC00472C0 0x62CAEEF8220.127.116.11/32 3 0xC0047358 0x62CAEB6818.104.22.168/32 3 0xC0047368 0x62CAEB0822.214.171.124/32 3 0xC0047370 0x62CAEAD8126.96.36.199/32 3 0xC0047378 0x62CAEAA8188.8.131.52/32 3 0xC0047380 0x62CAEA78184.108.40.206/24 3 0xC0047228 0x62CAF288255.255.255.255/32 3 0xC0047220 0x62CAF2B8========================================5 routes with less specific overlapping parent route
Table 1 describes the significant fields shown in the display.
show pxf feature cef
Displays PXF routing feature tables for CEF.
show pxf feature nat
Displays PXF routing feature tables for NAT.
AAA—Authentication, Authorization, and Accounting.
CBWFQ—Class-based weighted fair queueing. Class-based weighted fair queueing extends the standard weighted fair queueing (WFQ) functionality to provide support for user-defined traffic classes.
CEF—Cisco Express Forwarding.
MTRIE—A balanced-tree variation where the number of child nodes for each parent node may differ at each tree level, and the children of a parent node may be different types of nodes.
PXF—Parallel Express Forwarding.
QoS—Quality of Service.
RP—Route Processor. Processor module in the Cisco 7000 family routers that contains the CPU, system software, and most of the memory components that are used in the router.
VPN—Virtual Private Network. A system that permits dial-in networks to exist remotely to home networks, while giving the appearance of being directly connected. VPNs use L2TP and L2F to terminate the Layer 2 and higher parts of the network connection at the LNS instead of the LAC.
VRF—Virtual Route Forwarding. Initially, a router has only one global default routing/forwarding table. VRFs can be viewed as multiple disjoined routing/forwarding tables, where the routes of a user have no correlation with the routes of another user.
WFQ—Weighted fair queuing. Congestion management algorithm that identifies conversations (in the form of traffic streams), separates packets that belong to each conversation, and ensures that capacity is shared fairly between these individual conversations. WFQ is an automatic way of stabilizing network behavior during congestion and results in increased performance and reduced retransmission.