Traffic Shaping Overhead Accounting for ATM
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Table Of Contents
MQC—Traffic Shaping Overhead Accounting for ATM
Prerequisites for Traffic Shaping Overhead Accounting for ATM
Restrictions for Traffic Shaping Overhead Accounting for ATM
Information About Traffic Shaping Overhead Accounting for ATM
Benefits of Traffic Shaping Overhead Accounting for ATM
Subscriber Line Encapsulation Types
ATM Overhead Accounting and Hierarchical Policies
How to Configure Traffic Shaping Overhead Accounting for ATM
Configuring Traffic Shaping Overhead Accounting for ATM in a Hierarchical Policy
Verifying the Traffic Shaping Overhead Accounting for ATM Configuration
Configuration Examples for Traffic Shaping Overhead Accounting for ATM
Enabling Traffic Shaping Overhead Accounting for ATM: Example
Verifying Traffic Shaping Overhead Accounting for ATM: Example
Feature Information for MQC—Traffic Shaping Overhead Accounting for ATM
MQC—Traffic Shaping Overhead Accounting for ATM
First Published: December 4, 2006Last Updated: December 3, 2007The MQC—Traffic Shaping Overhead Accounting for ATM feature enables a broadband aggregation system (BRAS) to account for various encapsulation types when applying quality of service (QoS) functionality to packets. Typically, in Ethernet digital subscriber line (DSL) environments, the encapsulation from the router to the digital subscriber line access multiplexer (DSLAM) is Gigabit Ethernet and the encapsulation from DSLAM to customer premises equipment (CPE) is ATM. ATM overhead accounting enables the router to account for ATM encapsulation on the subscriber line and for the overhead added by cell segmentation. This enables the service provider to prevent overruns at the subscriber line and ensures that the router executes QoS features on the actual bandwidth used by ATM packets.
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Contents
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Prerequisites for Traffic Shaping Overhead Accounting for ATM
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Prerequisites for Traffic Shaping Overhead Accounting for ATM
Traffic classes must be configured using the class-map command.
Restrictions for Traffic Shaping Overhead Accounting for ATM
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Information About Traffic Shaping Overhead Accounting for ATM
Before configuring traffic shaping overhead accounting for ATM, you should understand the following concepts:
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Benefits of Traffic Shaping Overhead Accounting for ATM
The Traffic Shaping Overhead Accounting for ATM feature enables the broadband aggregation system (BRAS) to account for various encapsulation types when applying QoS to packets. Typically, in Ethernet Digital Subscriber Line (DSL) environments, the encapsulation from the BRAS to the DSLAM is Gigabit Ethernet and the encapsulation from the DSLAM to the CPE is ATM. ATM overhead accounting enables the BRAS to account for ATM encapsulation on the subscriber line and for the overhead added by cell segmentation. This enables the service provider to prevent overruns at the subscriber line and ensures that the router executes QoS features on the actual bandwidth used by ATM subscriber traffic.
BRAS and Encapsulation Types
BRAS uses the encapsulation type you configure for the DSLAM-CPE side to calculate the ATM overhead per packet, except for IP and PPP over Ethernet (PPPoE) packets. DSLAM-CPE encapsulation types are based on Subnetwork Access Protocol (SNAP) and multiplexer (MUX) formats of ATM Adaptation Layer 5 (AAL5), followed by routed bridge encapsulation (RBE), IP, PPPoE, or PPP over ATM (PPPoA). Because the DSLAM treats IP and PPPoE packets as payload, the BRAS does not account for these encapsulations.
On the BRAS-DSLAM side, encapsulation is IEEE 802.1Q VLAN or Q-in-Q (qinq). However, because the DSLAM removes the BRAS-DSLAM encapsulation, the BRAS does not account for 802.1Q or qinq encapsulation.
AAL5 segmentation processing adds the additional overhead of the 5-byte cell headers, the AAL5 Common Part Convergence Sublayer (CPCS) padding, and the AAL5 trailer. For more information, see the "ATM Overhead Calculation" section.
Subscriber Line Encapsulation Types
The router supports the following subscriber line encapsulation types:
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ATM Overhead Calculation
When calculating ATM overhead for traffic shaping, the router considers the encapsulation type used between the BRAS and the DSLAM, and between the DSLAM and CPE (see the "BRAS and Encapsulation Types" section).
Table 1 describes the fields the router uses for the various encapsulation types when calculating ATM overhead.
ATM Overhead Accounting and Hierarchical Policies
In hierarchical policies, you can enable ATM overhead accounting for shaping and bandwidth on top-level parent policies, middle-level child policies, and bottom-level child policies. If you enable ATM overhead accounting on a parent class-default class, you are not required to enable accounting on a child traffic class that does not contain the bandwidth or shape command. However, if you enable ATM overhead accounting on a child policy, then you must enable ATM overhead accounting on the parent policy. The parent and child classes must specify the same encapsulation type when enabling overhead accounting.
Table 2 summarizes the configuration requirements for ATM overhead accounting. For example, if overhead accounting is currently enabled for a parent policy, then accounting can be disabled or enabled on a child policy.
How to Configure Traffic Shaping Overhead Accounting for ATM
This section contains the following tasks.
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Configuring Traffic Shaping Overhead Accounting for ATM in a Hierarchical Policy
To configure traffic shaping overhead accounting for ATM in a hierarchical policy map structure, perform the following steps.
SUMMARY STEPS
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DETAILED STEPS
Step 1
enable
Example:Router> enable
Enables privileged EXEC mode.
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Step 2
configure terminal
Example:Router# configure terminal
Enters global configuration mode.
Step 3
policy-map policy-map-name
Example:Router(config)# policy-map Business
Creates or modifies the child policy and enters policy-map configuration mode.
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class class-map-name
Example:Router(config-pmap)# class video
Assigns the traffic class you specify to the policy map, and enters policy-map class configuration mode.
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bandwidth {bandwidth-kbps | percent percentage | remaining percent percentage} account {qinq | dot1q} aal5 subscriber-encap
Example:Router(config-pmap-c)# bandwidth 8000 account dot1q aal5 snap-pppoa
Enables Class-Based Weighted Fair Queuing (CBWFQ) on the basis of the keywords and arguments specified, such as the following:
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Step 6
exit
Example:Router(config-pmap-c)# exit
Exits policy-map class configuration mode.
Step 7
policy-map policy-map-name
Example:Router(config-pmap)# policy-map Premium
Creates or modifies the top-level parent policy.
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class class-default
Example:Router(config-pmap)# class class-default
Configures or modifies the parent class-default class.
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shape [average | peak] mean-rate [burst-size] [excess-burst-size] [account {qinq | dot1q} aal5 subscriber-encap
Example:Router(config-pmap-c)# shape 8000 account qinq aal5 snap-dot1q-rbe
Shapes traffic to the indicated bit rate and enables ATM overhead accounting on the basis of the keywords and arguments specified, such as the following:
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Step 10
service-policy policy-map-name
Example:Router(config-pmap-c)# service-policy Business
Applies a child policy to the parent class-default class.
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Step 11
end
Example:Router(config-pmap-c)# end
Exits policy-map class configuration mode.
Verifying the Traffic Shaping Overhead Accounting for ATM Configuration
To verify the traffic shaping overhead accounting for ATM configuration, complete the following steps.
SUMMARY STEPS
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DETAILED STEPS
Examples
The following sample output from the show policy-map command indicates that ATM overhead accounting is enabled for the class-default class. The BRAS-DSLAM encapsulation is dot1q and the subscriber line encapsulation is snap-rbe based on the AAL3 service.
Router# show policy-map unit-testPolicy Map unit-testClass class-defaultAverage Rate Traffic Shapingcir 10% account dot1q aal3 snap-rbeConfiguration Examples for Traffic Shaping Overhead Accounting for ATM
This section provides the following configuration examples:
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Enabling Traffic Shaping Overhead Accounting for ATM: Example
The following example shows how to enable ATM overhead accounting using a hierarchical policy map structure. The Child policy map has two classes: Business and Non-Business. The Business class has priority and is policed at 128000 kbps. The Non-Business class has ATM overhead accounting enabled and has a bandwidth of 20 percent of the available bandwidth. The Parent policy map shapes the aggregate traffic to 256000 kbps and enables ATM overhead accounting.
Notice that Layer 2 overhead accounting is not explicitly configured for the Business traffic class. If the class-default class of a parent policy has ATM overhead accounting enabled, you are not required to enable ATM overhead accounting on a child traffic class that does not contain the bandwidth or shape command. Therefore, in this example, the Business priority queue implicitly has ATM overhead accounting enabled because its parent class-default class has overhead accounting enabled.
policy-map Childclass Businessprioritypolice 128000class Non-Businessbandwidth percent 20 account dot1q aal5 snap-rbe-dot1qexitexitpolicy-map Parentclass class-defaultshape 256000 account dot1q aal5 snap-rbe-dot1qservice-policy ChildIn the following example, overhead accounting is enabled for bandwidth on the gaming and class-default class of the child policy map named subscriber_classes, and on the class-default class of the parent policy map named subscriber_line. The voip and video classes do not have accounting explicitly enabled; these classes have ATM overhead accounting implicitly enabled because the parent policy has overhead accounting enabled. Notice that the features in the parent and child policies use the same encapsulation type.
policy-map subscriber_classesclass voippriority level 1police 8000class videopriority level 2police 20class gamingbandwidth remaining percent 80 account aal5 snap-rbe-dot1qclass class-defaultbandwidth remaining percent 20 account aal5 snap-rbe-dot1qpolicy-map subscriber_lineclass class-defaultbandwidth remaining ratio 10 account aal5 snap-rbe-dot1qshape average 512 account aal5 snap-rbe-dot1qservice policy subscriber_classesVerifying Traffic Shaping Overhead Accounting for ATM: Example
The following output from the show policy-map interface command indicates that ATM overhead accounting is enabled for shaping and disabled for bandwidth:
Service-policy output:unit-testClass-map: class-default (match-any)100 packets, 1000 bytes30 second offered rate 800 bps, drop rate 0 bpsMatch: anyshape (average) cir 154400, bc 7720, be 7720target shape rate 154400overhead accounting: enabledbandwidth 30% (463 kbps)overhead accounting: disabledqueue limit 64 packets(queue depth/total drops/no-buffer drops) 0/0/0(packets output/bytes output) 100/1000The following output from the show running-config command indicates that ATM overhead accounting is enabled for shaping. The BRAS-DSLAM encapsulation is dot1q and the subscriber line encapsulation is snap-rbe based on the AAL5 service.
subscriber policy recording rules limit 64no mpls traffic-eng auto-bw timers frequency 0call rsvp-sync!controller T1 2/0framing sflinecode ami!controller T1 2/1framing sflinecode ami!!policy-map unit-testclass class-defaultshape average percent 10 account dot1q aal5 snap-rbe!Additional References
The following sections provide references related to traffic shaping overhead accounting for ATM.
Related Documents
Hierarchical policies, policy maps
Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.4
Cisco 10000 Series Router Quality of Service Configuration Guide
Modular Quality of Service (QoS) Command-Line Interface (CLI) (MQC)
Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.4
Policing and shaping traffic
Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.4
Cisco 10000 Series Router Quality of Service Configuration Guide
Standards
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
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MIBs
RFCs
No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.
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Technical Assistance
Command Reference
The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco IOS Quality of Service Solutions Command Reference at http://www.cisco.com/en/US/docs/ios/qos/command/reference/qos_book.html. For information about all Cisco IOS commands, go to the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or to the Cisco IOS Master Commands List.
bandwidth (policy-map class)
To specify or modify the bandwidth allocated for a class belonging to a policy map, or to enable ATM overhead accounting, use the bandwidth command in policy-map class configuration mode. To remove the bandwidth specified for a class, use the no form of this command.
bandwidth {bandwidth-kbps | remaining percent percentage | percent percentage} [account {qinq | dot1q} aal5 subscriber-encapsulation]
no bandwidth {bandwidth-kbps | remaining percent percentage | percent percentage} [account {qinq | dot1q} aal5 subscriber-encapsulation]
Cisco 10000 Series Router (PRE3)
bandwidth {bandwidth-kbps | percent percentage | remaining percent percentage} account {{{qinq | dot1q} {aal5 | aal3} {subscriber-encapsulation}} | {user-defined offset [atm]}}
no bandwidth {bandwidth-kbps | percent percentage | remaining percent percentage} account {{{qinq | dot1q} {aal5 | aal3} {subscriber-encapsulation}} | {user-defined offset [atm]}}
Syntax Description
Command Default
No bandwidth is specified.
ATM overhead accounting is disabled.
Command Modes
Policy-map class configuration (config-pmap-c)
Command History
Usage Guidelines
You should use the bandwidth command when you configure a policy map for a class defined by the class-map command. The bandwidth command specifies the bandwidth for traffic in that class. Class-based weighted fair queueing (CBWFQ) derives the weight for packets belonging to the class from the bandwidth allocated to the class. CBWFQ then uses the weight to ensure that the queue for the class is serviced fairly.
Specifying Bandwidth as a Percentage for All Supported Platforms Except the Cisco 10000 Series Routers
Besides specifying the amount of bandwidth in kilobits per second (kbps), you can specify bandwidth as a percentage of either the available bandwidth or the total bandwidth. During periods of congestion, the classes are serviced in proportion to their configured bandwidth percentages. The bandwidth percentage is based on the interface bandwidth or when used in a hierarchical policy. Available bandwidth is equal to the interface bandwidth minus the sum of all bandwidths reserved by the Resource Reservation Protocol (RSVP) feature, the IP RTP Priority feature, and the low latency queueing (LLQ) feature.
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Specifying Bandwidth as a Percentage for the Cisco 10000 Series Routers
Besides specifying the amount of bandwidth in kilobits per second (kbps), you can specify bandwidth as a percentage of either the available bandwidth or the total bandwidth. During periods of congestion, the classes are serviced in proportion to their configured bandwidth percentages. The minimum bandwidth percentage is based on the nearest parent shape rate.
Note
The router converts the specified bandwidth to the nearest multiple of 1/255 (ESR-PRE1) or 1/65,535 (ESR-PRE2) of the interface speed. Use the show policy-map interface command to display the actual bandwidth.
Restrictions for All Supported Platforms
The following restrictions apply to the bandwidth command:
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For more information on bandwidth allocation, refer to the chapter "Congestion Management Overview" in the Cisco IOS Quality of Service Solutions Configuration Guide.
Note that when the policy map containing class policy configurations is attached to the interface to stipulate the service policy for that interface, available bandwidth is assessed. If a policy map cannot be attached to a particular interface because of insufficient interface bandwidth, then the policy is removed from all interfaces to which it was successfully attached.
Modular QoS Command-Line Interface Queue Limits
The bandwidth command can be used with the Modular Quality of Service Command-line Interface (MQC) to specify the bandwidth for a particular class. When used with the MQC, the bandwidth command uses a default queue limit for the class. This queue limit can be modified using the queue-limit command, thereby overriding the default set by the bandwidth command.
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Cisco 10000 Series Router
The Cisco 10000 series router supports the bandwidth command on outbound interfaces only. It does not support this command on inbound interfaces.
On the PRE2, you specify a bandwidth value and a unit for the bandwidth value. Valid values for the bandwidth are from 1 to 2488320000 and units are bps, kbps, mbps, gbps. The default unit is kbps. For example, the following commands configure a bandwidth of 10000 bps and 10000 kbps on the PRE2:
bandwidth 10000 bpsbandwidth 10000On the PRE3, you only specify a bandwidth value. Because the unit is always kbps, the PRE3 does not support the unit argument. Valid values are from 1 to 2000000. For example, the following command configures a bandwidth of 128,000 kbps on the PRE3:
bandwidth 128000The PRE3 accepts the PRE2 bandwidth command only if the command is used without the unit argument. The PRE3 rejects the PRE2 bandwidth command if the specified bandwidth is outside the valid PRE3 bandwidth value range (1 to 2000000).
Besides specifying the amount of bandwidth in kilobits per second (kbps), you can specify bandwidth as a percentage of either the available bandwidth or the total bandwidth. During periods of congestion, the classes are serviced in proportion to their configured bandwidth percentages. The bandwidth percentage is based on the interface bandwidth or when used in a hierarchical policy the minimum bandwidth percentage is based on the nearest parent shape rate.
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The router converts the specified bandwidth to the nearest multiple of 1/255 (PRE1) or 1/65535 (PRE2, PRE3) of the interface speed. Use the show policy-map interface command to display the actual bandwidth.
Usage Guidelines for Overhead Accounting for ATM (Cisco 10000 Series Router)
When configuring ATM overhead accounting, you must specify the BRAS-DSLAM, DSLAM-CPE, and subscriber line encapsulation types. The router supports the following subscriber line encapsulation types:
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The router calculates the offset size unless you specify the user-defined offset option.
For hierarchical policies, configure ATM overhead accounting in the following ways:
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The encapsulation types must match for the child and parent policies.
The user-defined offset values must match for the child and parent policies.
Examples
Cisco 10000 Series Router
In the following example, the policy map named VLAN guarantees 30 percent of the bandwidth to the class named Customer1 and 60 percent of the bandwidth to the class named Customer2. If you apply the VLAN policy map to a 1-Mbps link, 300 kbps (30 percent of 1 Mbps) is guaranteed to class Customer1 and 600 kbps (60 percent of 1 Mbps) is guaranteed to class Customer2, with 100 kbps remaining for the class-default class. If the class-default class does not need additional bandwidth, the unused 100 kbps is available for use by class Customer1 and class Customer2. If both classes need the bandwidth, they share it in proportion to the configured rates. In this example, the sharing ratio is 30:60 or 1:2:
Router(config)# policy-map VLANRouter(config-pmap)# class Customer1Router(config-pmap-c)# bandwidth percent 30Router(config-pmap-c)# exitRouter(config-pmap)# class Customer2Router(config-pmap-c)# bandwidth percent 60CBWFQ Bandwidth Guarantee Example
The following example creates a policy map with two classes, shows how bandwidth is guaranteed when only CBWFQ is configured, and attaches the policy to serial interface 3/2/1:
Router(config)# policy-map policy1Router(config-pmap)# class class1Router(config-pmap-c)# bandwidth percent 50Router(config-pmap-c)# exitRouter(config-pmap)# class class2Router(config-pmap-c)# bandwidth percent 25Router(config-pmap-c)# exitRouter(config-pmap)# exitRouter(config)# interface serial3/2/1Router(config-if)# service output policy1Router(config-if)# endThe following output from the show policy-map command shows the configuration for the policy map called policy1:
Router# show policy-map policy1Policy Map policy1Class class1Weighted Fair QueueingBandwidth 50 (%) Max Threshold 64 (packets)Class class2Weighted Fair QueueingBandwidth 25 (%) Max Threshold 64 (packets)The output from the show policy-map interface command shows that 50 percent of the interface bandwidth is guaranteed for the class called class1, and 25 percent is guaranteed for the class called class2. The output displays the amount of bandwidth as both a percentage and a number of kbps.
Router# show policy-map interface serial3/2Serial3/2Service-policy output:policy1Class-map:class1 (match-all)0 packets, 0 bytes5 minute offered rate 0 bps, drop rate 0 bpsMatch:noneWeighted Fair QueueingOutput Queue:Conversation 265Bandwidth 50 (%)Bandwidth 772 (kbps) Max Threshold 64 (packets)(pkts matched/bytes matched) 0/0(depth/total drops/no-buffer drops) 0/0/0Class-map:class2 (match-all)0 packets, 0 bytes5 minute offered rate 0 bps, drop rate 0 bpsMatch:noneWeighted Fair QueueingOutput Queue:Conversation 266Bandwidth 25 (%)Bandwidth 386 (kbps) Max Threshold 64 (packets)(pkts matched/bytes matched) 0/0(depth/total drops/no-buffer drops) 0/0/0Class-map:class-default (match-any)0 packets, 0 bytes5 minute offered rate 0 bps, drop rate 0 bpsMatch:anyIn this example, serial interface 3/2 has a total bandwidth of 1544 kbps. During periods of congestion, 50 percent (or 772 kbps) of the bandwidth is guaranteed to the class called class1, and 25 percent (or 386 kbps) of the link bandwidth is guaranteed to the class called class2.
CBWFQ and LLQ Bandwidth Allocation Example
In the following example, the interface has a total bandwidth of 1544 kbps. During periods of congestion, 50 percent (or 772 kbps) of the bandwidth is guaranteed to the class called class1, and 25 percent (or 386 kbps) of the link bandwidth is guaranteed to the class called class2.
The following sample output from the show policy-map command shows the configuration of a policy map called p1:
Router# show policy-map p1Policy Map p1Class voiceWeighted Fair QueueingStrict PriorityBandwidth 500 (kbps) Burst 12500 (Bytes)Class class1Weighted Fair QueueingBandwidth remaining 50 (%) Max Threshold 64 (packets)Class class2Weighted Fair QueueingBandwidth remaining 25 (%) Max Threshold 64 (packets)The following output from the show policy-map interface command on serial interface 3/2 shows that 500 kbps of bandwidth is guaranteed for the class called voice1. The classes called class1 and class2 receive 50 percent and 25 percent of the remaining bandwidth, respectively. Any unallocated bandwidth is divided proportionally among class1, class2, and any best-effort traffic classes.
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Router# show policy-map interface serial3/2Serial3/2Service-policy output:p1Class-map:voice (match-all)0 packets, 0 bytes5 minute offered rate 0 bps, drop rate 0 bpsMatch:ip precedence 5Weighted Fair QueueingStrict PriorityOutput Queue:Conversation 264Bandwidth 500 (kbps) Burst 12500 (Bytes)(pkts matched/bytes matched) 0/0(total drops/bytes drops) 0/0Class-map:class1 (match-all)0 packets, 0 bytes5 minute offered rate 0 bps, drop rate 0 bpsMatch:noneWeighted Fair QueueingOutput Queue:Conversation 265Bandwidth remaining 50 (%) Max Threshold 64 (packets)(pkts matched/bytes matched) 0/0(depth/total drops/no-buffer drops) 0/0/0Class-map:class2 (match-all)0 packets, 0 bytes5 minute offered rate 0 bps, drop rate 0 bpsMatch:noneWeighted Fair QueueingOutput Queue:Conversation 266Bandwidth remaining 25 (%) Max Threshold 64 (packets)(pkts matched/bytes matched) 0/0(depth/total drops/no-buffer drops) 0/0/0Class-map:class-default (match-any)0 packets, 0 bytes5 minute offered rate 0 bps, drop rate 0 bpsMatch:anyTraffic Shaping Overhead Accounting for ATM Example
When a parent policy has ATM overhead accounting enabled, you are not required to enable ATM overhead accounting on a child traffic class that does not contain the bandwidth or shape command. In the following configuration example, ATM overhead accounting is enabled for bandwidth on the gaming and class-default class of the child policy map named subscriber_classes, and on the class-default class of the parent policy map named subscriber_line. The voip and video classes do not have ATM overhead accounting explicitly enabled; these priority queues have overhead accounting implicitly enabled because ATM overhead accounting is enabled on the parent policy. Notice that the features in the parent and child policies use the same encapsulation type.
policy-map subscriber_classesclass voippriority level 1police 8000class videopriority level 2police 20class gamingbandwidth remaining percent 80 account aal5 snap-rbe-dot1qclass class-defaultbandwidth remaining percent 20 account aal5 snap-rbe-dot1qpolicy-map subscriber_lineclass class-defaultbandwidth remaining ratio 10 account aal5 snap-rbe-dot1qshape average 512 account aal5 snap-rbe-dot1qservice policy subscriber_classesIn the following example, the router will use 20 overhead bytes and ATM cell tax in calculating ATM overhead. The child and parent policies contain the required matching offset values. The parent policy is attached to virtual template 1.
policy-map childclass class1bandwidth 500 account user-defined 20 atmclass class2shape average 30000 account user-defined 20 atmpolicy-map parentclass class-defaultshape average 30000 account user-defined 20 atmservice-policy childinterface virtual-template 1service-policy output parentRelated Commands
shape (policy-map class)
To shape traffic to the indicated bit rate according to the algorithm specified, or to enable ATM overhead accounting, use the shape command in policy-map class configuration mode. To remove shaping and leave the traffic unshaped, use the no form of this command.
shape [average | peak] mean-rate [burst-size] [excess-burst-size]
no shape [average | peak]
Cisco 10000 Series Router (PRE1)
shape [average | peak] mean-rate [[burst-size] [excess-burst-size]] [account {qinq | dot1q} aal5 subscriber-encap]
no shape [average | peak] mean-rate [[burst-size] [excess-burst-size]] [account {qinq | dot1q} aal5 subscriber-encap]
Cisco 10000 Series Router (PRE2)
shape [average] mean-rate [unit] [[burst-size] [excess-burst-size]] [account {qinq | dot1q} aal5 subscriber-encapsulation]
no shape [average] mean-rate [unit] [[burst-size] [excess-burst-size]] [account {qinq | dot1q} aal5 subscriber-encapsulation]
Cisco 10000 Series Router (PRE3)
shape [average] mean-rate [[burst-size] [excess-burst-size]] account {{{qinq | dot1q} {aal5 | aal3} {subscriber-encapsulation}} | {user-defined offset [atm]}}
no shape [average] mean-rate [[burst-size] [excess-burst-size]] account {{{qinq | dot1q} {aal5 | aal3} {subscriber-encapsulation}} | {user-defined offset [atm]}}
Syntax Description
Command Default
When the excess burst size (Be) is not configured, the default Be value is equal to the committed burst size (Bc). For more information about burst size defaults, see the "Usage Guidelines" section.
Traffic shaping overhead accounting for ATM is disabled.
Command Modes
Policy-map class configuration (config-pmap-c)
Command History
Usage Guidelines
The measurement interval is the committed burst size (Bc) divided by committed information rate (CIR). Bc cannot be set to 0. If the measurement interval is too large (greater than 128 milliseconds), the system subdivides it into smaller intervals.
If you do not specify the committed burst size (Bc) and the excess burst size (Be), the algorithm decides the default values for the shape entity. The algorithm uses a 4 milliseconds measurement interval, so Bc is CIR * (4 / 1000).
Burst sizes larger than the default committed burst size (Bc) need to be explicitly specified. The larger the Bc, the longer the measurement interval. A long measurement interval may affect voice traffic latency, if applicable.
When the excess burst size (Be) is not configured, the default value is equal to the committed burst size (Bc).
Traffic Shaping on the Cisco 10000 Series Performance Routing Engine
The Cisco 10000 series router does not support the peak keyword.
On the PRE2, you specify a shape rate and a unit for the rate. Valid values for the rate are from 1 to 2488320000 and units are bps, kbps, mbps, gbps. The default unit is kbps. For example:
shape 128000 bpsOn the PRE3, you only need to specify a shape rate. Because the unit is always bps on the PRE3, the unit argument is not available. Valid values for the shape rate are from 1000 to 2488320000.
shape 1000The PRE3 accepts the PRE2 shape command as a hidden command. However, the PRE3 rejects the PRE2 shape command if the specified rate is outside the valid PRE3 shape rate range (1000 to 2488320000).
Traffic Shaping Overhead Accounting for ATM (Cisco 10000 Series Router)
When configuring ATM overhead accounting on the Cisco 10000 series router, you must specify the BRAS-DSLAM, DSLAM-CPE, and subscriber line encapsulation types. The router supports the following subscriber line encapsulation types:
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For hierarchical policies, configure ATM overhead accounting in the following ways:
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The encapsulation types must match for the child and parent policies.
The user-defined offset values must match for the child and parent policies.
Examples
The following example configures a shape entity with a CIR of 1 Mbps and attaches the policy map called dts-interface-all-action to interface pos1/0/0:
policy-map dts-interface-all-actionclass class-interface-allshape average 1000000interface pos1/0/0service-policy output dts-interface-all-actionTraffic Shaping Overhead Accounting for ATM
When a parent policy has ATM overhead accounting enabled for shaping, you are not required to enable accounting at the child level using the police command. In the following configuration example, ATM overhead accounting is enabled for bandwidth on the gaming and class-default class of the child policy map named subscriber_classes, and on the class-default class of the parent policy map named subscriber_line. The voip and video classes do not have ATM overhead accounting explicitly enabled. These priority classes have ATM overhead accounting implicitly enabled because the parent policy has ATM overhead accounting enabled. Notice that the features in the parent and child policies use the same encapsulation type.
policy-map subscriber_classesclass voippriority level 1police 8000class videopriority level 2police 20class gamingbandwidth remaining percent 80 account aal5 snap-rbe-dot1qclass class-defaultbandwidth remaining percent 20 account aal5 snap-rbe-dot1qpolicy-map subscriber_line class class-defaultbandwidth remaining ratio 10 account aal5 snap-rbe-dot1qshape average 512 account aal5 snap-rbe-dot1qservice policy subscriber_classesIn the following example, the router will use 20 overhead bytes and ATM cell tax in calculating ATM overhead. The child and parent policies contain the required matching offset values. The parent policy is attached to virtual template 1.
policy-map childclass class1bandwidth 500 account user-defined 20 atmclass class2shape average 30000 account user-defined 20 atmpolicy-map parentclass class-defaultshape average 30000 account user-defined 20 atmservice-policy childinterface virtual-template 1service-policy output parentRelated Commands
show policy-map
To display the configuration of all classes for a specified service policy map or of all classes for all existing policy maps, use the show policy-map command in user EXEC or privileged EXEC mode.
show policy-map [policy-map]
Syntax Description
policy-map
(Optional) Name of the service policy map whose complete configuration is to be displayed. The name can be a maximum of 40 characters.
Command Default
All existing policy map configurations are displayed.
Command Modes
User EXEC (>)
Privileged EXEC (#)Command History
Usage Guidelines
The show policy-map command displays the configuration of a policy map created using the policy-map command. You can use the show policy-map command to display all class configurations comprising any existing service policy map, whether or not that policy map has been attached to an interface. The command displays:
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Examples
This section provides sample output from typical show policy-map commands. Depending upon the interface or platform in use and the options enabled (for example, Weighted Fair Queueing [WFQ]), the output you see may vary slightly from the ones shown below.
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Weighted Fair Queueing: Example
The following example displays the contents of the service policy map called po1. In this example, WFQ is enabled.
Router# show policy-map po1Policy Map po1 Weighted Fair Queueing Class class1 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class2 Bandwidth 937 (kbps) Max thresh 64 (packets)Class class3 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class4 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class5 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class6 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class7 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class8 Bandwidth 937 (kbps) Max thresh 64 (packets)The following example displays the contents of all policy maps on the router. Again, WFQ is enabled.
Router# show policy-mapPolicy Map poH1 Weighted Fair Queueing Class class1 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class2 Bandwidth 937 (kbps) Max thresh 64 (packets)Class class3 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class4 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class5 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class6 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class7 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class8 Bandwidth 937 (kbps) Max thresh 64 (packets)Policy Map policy2 Weighted Fair Queueing Class class1 Bandwidth 300 (kbps) Max thresh 64 (packets) Class class2 Bandwidth 300 (kbps) Max thresh 64 (packets)Class class3 Bandwidth 300 (kbps) Max thresh 64 (packets) Class class4 Bandwidth 300 (kbps) Max thresh 64 (packets) Class class5 Bandwidth 300 (kbps) Max thresh 64 (packets) Class class6 Bandwidth 300 (kbps) Max thresh 64 (packets)Table 3 describes the significant fields shown in the display.
Frame Relay Voice-Adaptive Traffic-Shaping: Example
The following sample output for the show-policy map command indicates that Frame Relay voice-adaptive traffic-shaping is configured in the class-default class in the policy map "MQC-SHAPE-LLQ1" and that the deactivation timer is set to 30 seconds.
Router# show policy-mapPolicy Map VSD1Class VOICE1Strict PriorityBandwidth 10 (kbps) Burst 250 (Bytes)Class SIGNALS1Bandwidth 8 (kbps) Max Threshold 64 (packets)Class DATA1Bandwidth 15 (kbps) Max Threshold 64 (packets)Policy Map MQC-SHAPE-LLQ1Class class-defaultTraffic ShapingAverage Rate Traffic ShapingCIR 63000 (bps) Max. Buffers Limit 1000 (Packets)Adapt to 8000 (bps)Voice Adapt Deactivation Timer 30 Secservice-policy VSD1Table 4 describes the significant fields shown in the display.
Traffic Policing: Example
The following is sample output from the show policy-map command. This sample output displays the contents of a policy map called "policy1." In policy 1, traffic policing on the basis of a committed information rate (CIR) of 20 percent has been configured, and the bc and be have been specified in milliseconds. As part of the traffic policing configuration, optional conform, exceed, and violate actions have been specified.
Router# show policy-map policy1Policy Map policy1Class class1police cir percent 20 bc 300 ms pir percent 40 be 400 msconform-action transmitexceed-action dropviolate-action dropTable 5 describes the significant fields shown in the display.
Two-Rate Traffic Policing: Example
The following is sample output from the show policy-map command when two-rate traffic policing has been configured. As shown below, two-rate traffic policing has been configured for a class called "police." In turn, the class called police has been configured in a policy map called "policy1." Two-rate traffic policing has been configured to limit traffic to an average committed rate of 500 kbps and a peak rate of 1 Mbps.
Router(config)# class-map policeRouter(config-cmap)# match access-group 101Router(config-cmap)# policy-map policy1Router(config-pmap)# class policeRouter(config-pmap-c)# police cir 500000 bc 10000 pir 1000000 be 10000 conform-action transmit exceed-action set-prec-transmit 2 violate-action dropRouter(config-pmap-c)# interface serial3/0Router(config-pmap-c)# exitRouter(config-pmap)# exitRouter(config)# interface serial3/0Router(config-if)# service-policy output policy1Router(config-if)# endThe following sample output shows the contents of the policy map called "policy1":Router# show policy-map policy1Policy Map policy1Class policepolice cir 500000 conform-burst 10000 pir 1000000 peak-burst 10000 conform-actiontransmit exceed-action set-prec-transmit 2 violate-action dropTraffic marked as conforming to the average committed rate (500 kbps) will be sent as is. Traffic marked as exceeding 500 kbps, but not exceeding 1 Mbps, will be marked with IP Precedence 2 and then sent. All traffic exceeding 1 Mbps will be dropped. The burst parameters are set to 10000 bytes.
Table 6 describes the significant fields shown in the display.
Multiple Traffic Policing Actions: Example
The following is sample output from the show policy-map command when the Policer Enhancement—Multiple Actions feature has been configured. The following sample output from the show policy-map command displays the configuration for a service policy called "police." In this service policy, traffic policing has been configured to allow multiple actions for packets marked as conforming to, exceeding, or violating the CIR or the PIR shown in the example.
Router# show policy-map policePolicy Map policeClass class-defaultpolice cir 1000000 bc 31250 pir 2000000 be 31250conform-action transmitexceed-action set-prec-transmit 4exceed-action set-frde-transmitviolate-action set-prec-transmit 2violate-action set-frde-transmitPackets conforming to the specified CIR (1000000 bps) are marked as conforming packets. These are transmitted unaltered.
Packets exceeding the specified CIR (but not the specified PIR, 2000000 bps) are marked as exceeding packets. For these packets, the IP Precedence level is set to 4, the discard eligibility (DE) bit is set to 1, and the packet is transmitted.
Packets exceeding the specified PIR are marked as violating packets. For these packets, the IP Precedence level is set to 2, the DE bit is set to 1, and the packet is transmitted.
Note
Table 7 describes the significant fields shown in the display.
Explicit Congestion Notification: Example
The following is sample output from the show policy-map command when the WRED—Explicit Congestion Notification (ECN) feature has been configured. The words "explicit congestion notification" (along with the ECN marking information) included in the output indicate that ECN has been enabled.
Router# show policy-mapPolicy Map pol1Class class-defaultWeighted Fair QueueingBandwidth 70 (%)exponential weight 9explicit congestion notificationclass min-threshold max-threshold mark-probability--------------------------------------------------------------------------------------------------------------------0 - - 1/101 - - 1/102 - - 1/103 - - 1/104 - - 1/105 - - 1/106 - - 1/107 - - 1/10rsvp - - 1/10Table 8 describes the significant fields shown in the display.
Modular QoS CLI (MQC) Unconditional Packet Discard: Example
The following example displays the contents of the policy map called "policy1." All the packets belonging to the class called "c1" are discarded.
Router# show policy-map policy1Policy Map policy1Class c1dropTable 9 describes the significant fields shown in the display.
Percentage-Based Policing and Shaping: Example
The following example displays the contents of two service policy maps—one called "policy1" and one called "policy2." In policy1, traffic policing based on a CIR of 50 percent has been configured. In policy 2, traffic shaping based on an average rate of 35 percent has been configured.
Router# show policy-map policy1Policy Map policy1 class class1 police cir percent 50Router# show policy-map policy2Policy Map policy2 class class2 shape average percent 35The following example displays the contents of the service policy map called "po1":
Router# show policy-map po1Policy Map po1 Weighted Fair Queueing Class class1 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class2 Bandwidth 937 (kbps) Max thresh 64 (packets)Class class3
Bandwidth 937 (kbps) Max thresh 64 (packets)
Class class4
Bandwidth 937 (kbps) Max thresh 64 (packets)
The following example displays the contents of all policy maps on the router:Router# show policy-mapPolicy Map poH1 Weighted Fair Queueing Class class1 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class2 Bandwidth 937 (kbps) Max thresh 64 (packets)Class class3 Bandwidth 937 (kbps) Max thresh 64 (packets) Class class4 Bandwidth 937 (kbps) Max thresh 64 (packets) Policy Map policy2 Weighted Fair Queueing Class class1 Bandwidth 300 (kbps) Max thresh 64 (packets) Class class2 Bandwidth 300 (kbps) Max thresh 64 (packets)Class class3 Bandwidth 300 (kbps) Max thresh 64 (packets) Class class4 Bandwidth 300 (kbps) Max thresh 64 (packets)Table 10 describes the significant fields shown in the display.
Enhanced Packet Marking: Example
The following sample output from the show policy-map command displays the configuration for policy maps called "policy1" and "policy2".
In "policy1", a table map called "table-map-cos1" has been configured to determine the precedence based on the class of service (CoS) value. Policy map "policy 1" converts and propagates the packet markings defined in the table map called "table-map-cos1".
The following sample output from the show policy-map command displays the configuration for service polices called "policy1" and "policy2". In "policy1", a table map called "table-map1" has been configured to determine the precedence according to the CoS value. In "policy2", a table map called "table-map2" has been configured to determine the CoS value according to the precedence value.
Router# show policy-map policy1Policy Map policy1Class class-defaultset precedence cos table table-map1Router# show policy-map policy2Policy Map policy2Class class-defaultset cos precedence table table-map2Table 11 describes the fields shown in the display.
Bandwidth-Remaining Ratio: Example
The following sample output for the show policy-map command indicates that the class-default class of the policy map named vlan10_policy has a bandwidth-remaining ratio of 10. When congestion occurs, the scheduler allocates class-default traffic 10 times the unused bandwidth allocated in relation to other subinterfaces.
Router# show policy-map vlan10_policyPolicy Map vlan10_policyClass class-defaultAverage Rate Traffic Shapingcir 1000000 (bps)bandwidth remaining ratio 10service-policy child_policyTable 12 describes the fields shown in the display.
ATM Overhead Accounting: Example
The following sample output for the show policy-map command indicates that ATM overhead accounting is enabled for the class-default class. The BRAS-DSLAM encapsulation is dot1q and the subscriber encapsulation is snap-rbe for the AAL5 service.
Policy Map unit-testClass class-defaultAverage Rate Traffic Shapingcir 10% account dot1q aal5 snap-rbeTable 13 describes the significant fields shown in the display.
Tunnel Marking: Example
In this sample output of the show policy-map command, the character string "ip precedence tunnel 4" indicates that L2TPv3 tunnel marking has been configured to set the IP precedence value to 4 in the header of a tunneled packet.
Router# show policy-mapPolicy Map TUNNEL_MARKINGClass MATCH_FRDEset ip precedence tunnel 4Table 14 describes the fields shown in the display.
Related Commands
show running-config
To display the contents of the current running configuration file or the configuration for a specific module, Layer 2 VLAN, class map, interface, map class, policy map, or virtual circuit (VC) class, use the show running-config command in user EXEC or privileged EXEC mode.
Supported Platforms Other than the Cisco 7600 Series Router
show running-config [options]
Cisco 7600 Series Router
show running-config [module number | vlan vlan-id]
Syntax Description
Command Default
Displays the entire contents of the running configuration file.
Command Modes
User EXEC (>)
Privileged EXEC (#)Command History
Usage Guidelines
The show running-config command is technically a command alias of the more system:running-config command. Although more commands are recommended (due to their uniform structure across platforms and their expandable syntax), the show running-config command remains enabled to accommodate its widespread use, and to allow typing shortcuts such as show run.
The show running-config interface command is useful when there are multiple interfaces and you want to look at the configuration of a specific interface.
The linenum keyword causes line numbers to be displayed in the output. This option is useful for identifying a particular portion of a very large configuration.
Cisco 7600 Series Router
In some cases, you might see a difference in the duplex mode that is displayed between the show interfaces command and the show running-config command. The duplex mode that is displayed in the show interfaces command is the actual duplex mode that the interface is running. The show interfaces command shows the operating mode for an interface, while the show running-config command shows the configured mode for an interface.
The show running-config command output for an interface might display the duplex mode but no configuration for the speed. This output indicates that the interface speed is configured as auto and that the duplex mode shown becomes the operational setting once the speed is configured to something other than auto. With this configuration, it is possible that the operating duplex mode for that interface does not match the duplex mode that is shown with the show running-config command.
Examples
For Platforms Other than the Cisco 7600 Router
The following example applies shows the configuration for serial interface 1:
Router# show running-config interface serial 1Building configuration...Current configuration:!interface Serial1no ip addressno ip directed-broadcastno ip route-cacheno ip mroute-cacheshutdownendThe following example shows the configuration for Ethernet interface 0/0. Line numbers are displayed in the output.
Router# show running-config interface ethernet 0/0 linenumBuilding configuration...Current configuration : 104 bytes1 : !2 : interface Ethernet0/03 : ip address 10.4.2.63 255.255.255.04 : no ip route-cache5 : no ip mroute-cache6 : endThe following example shows how to set line numbers in the command output and then use the output modifier to start the display at line 10:
Router# show running-config linenum | begin 1010 : boot-start-marker11 : boot-end-marker12 : !13 : no logging buffered14 : enable password #####15 : !16 : spe 1/0 1/717 : firmware location bootflash:mica-modem-pw.172.6.0.0.bin18 : !19 : !20 : resource-pool disable21 : !22 : no aaa new-model23 : ip subnet-zero24 : ip domain name cisco.com25 : ip name-server 172.16.11.4826 : ip name-server 172.16.2.13327 : !28 : !29 : isdn switch-type primary-5ess30 : !...126 : endATM Overhead Accounting Example
The following sample output for the show running-config command indicates that accounting is enabled for shaping. The BRAS-DSLAM encapsulation is qinq and the subscriber line encapsulation is snap-rbe based on the AAL5 service.
subscriber policy recording rules limit 64no mpls traffic-eng auto-bw timers frequency 0call rsvp-sync!controller T1 2/0framing sflinecode ami!controller T1 2/1framing sflinecode ami!!policy-map unit-testclass class-defaultshape average percent 10 account qinq aal5 snap-rbe!Cisco 7600 Series Router Example
This example shows how to display the module and status configuration for all modules:
Router#show running-configBuilding configuration...Current configuration:!version 12.0service timestamps debug datetime localtimeservice timestamps log datetime localtimeno service password-encryption!hostname Router!boot buffersize 126968boot system flash slot0:halleyboot bootldr bootflash:c6msfc-boot-mz.120-6.5T.XE1.0.83.binenable password lab!clock timezone Pacific -8clock summer-time Daylight recurringredundancymain-cpuauto-sync standard!ip subnet-zero!ip multicast-routingip dvmrp route-limit 20000ip cefmls flow ip destinationmls flow ipx destinationcns event-service server!spanning-tree portfast bpdu-guardspanning-tree uplinkfastspanning-tree vlan 200 forward-time 21port-channel load-balance sdip!!!shutdown!!...Related Commands
Feature Information for MQC—Traffic Shaping Overhead Accounting for ATM
Table 15 lists the release history for this feature.
Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS 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
Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.
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