MQC-Based Frame Relay Traffic Shaping

MQC is used to configure FRTS. MQC is a framework that provides a clear separation between a classification policy and the specification of other parameters that act on the results of that applied classification policy.

Before this feature was introduced in Cisco IOS Release 12.2(13)T, FRTS for the Cisco routers specified in the MQC Overview section could be configured only by using traditional FRTS commands (refer to the How to Configure MQC-Based Frame Relay Traffic Shaping section for more information). With the addition of the MQC-Based Frame Relay Traffic Shaping feature, FRTS can be configured on routers throughout the Cisco router product line by using MQC.

Broadly, MQC is configured and implemented as follows:

• Define a traffic class with the class-map command.
• Create a service policy by associating the traffic class with one or more QoS features (using the policy-map command).
• Attach the service policy to the interface with the service-policy command.

For more detailed information on MQC, refer to the document Modular Quality of Service Command-Line Interface. MQC commands used for FRTS are further explained in the How to Configure MQC-Based Frame Relay Traffic Shaping section of this document.

FRTS allows you to control the traffic going out through a PVC in order to match its flow to the speed of the remote target interface and to ensure that the traffic conforms to the parameters that have been set for it. Traffic that matches a particular profile can be shaped to meet downstream requirements, thereby eliminating the bottlenecks that occur in topologies that have data-rate mismatches.

The primary reasons you would use FRTS are the following:

• To allow high-priority packets to take precedence over other packets as they are encapsulated and forwarded over the Frame Relay network. FRTS is useful for applications such as VoIP and streaming video, which require a low latency to be effective.
• To control access to available bandwidth.
• To ensure that traffic conforms to the parameters established for it.
• To regulate the flow of traffic in order to avoid congestion that can occur when the sent traffic exceeds the access speed of its remote target interface.
• To eliminate bottlenecks in Frame Relay networks that have high-speed connections at the central site and low-speed connections at branch sites by configuring rate enforcement to limit the rate at which data is sent on the virtual circuit (VC) at the central site. Rate enforcement is a peak rate configured to limit outbound traffic.

The MQC-Based Frame Relay Traffic Shaping feature allows the Cisco routers specified in the Feature Design of MQC-Based Frame Relay Traffic Shaping section to have FRTS configured using MQC instead of traditional FRTS commands.

Before this feature was introduced in Cisco IOS Release 12.2(13)T, FRTS for the Cisco routers specified in the Feature Design of MQC-Based Frame Relay Traffic Shaping section could be configured only by using traditional FRTS commands (for example, the frame-relay traffic-shaping command). For traditional FRTS, all traffic shaping and fragmentation values are entered under the map class. Traffic shaping is defined by entering the map-class frame-relay command, then entering the traffic shaping and, optionally, fragmentation values.

For routers in the Cisco 7500 and above product range, Distributed Traffic Shaping (DTS) is used for traffic shaping. With DTS, the traffic-shaping values are configured by entering the policy-mapcommand, then entering the traffic-shaping values. However, fragmentation values are still entered under the map class--the map-class frame-relay command is still used before any fragmentation values are entered.

The traffic-shaping commands supported by the MQC-Based Frame Relay Traffic Shaping feature are listed in the Supported MQC Frame Relay Traffic Shaping Commands section.

CBWFQ can also be configured under the policy map by entering the policy-mapcommand and then entering the traffic-shaping CBWFQ values.

Note	Configuring traffic shaping using MQC and configuring traffic shaping using traditional FRTS commands are mutually exclusive. Traffic shaping cannot be configured on the same interface using both methods.

• Supported MQC Frame Relay Traffic Shaping Commands
  

MQC allows users to specify a traffic class independently of QoS parameters.

The MQC-Based Frame Relay Traffic Shaping feature allows users to apply FRTS parameters using MQC across the entire Cisco router product line.

This feature ensures that FRTS is defined in the same manner for routers across the Cisco router product line, rather than only for routers in the Cisco 7500 and above product range.

Before this feature was introduced in Cisco IOS Release 12.2(13)T, FRTS for the Cisco routers specified in the Benefits of MQC-Based Frame Relay Traffic Shaping section could be defined only by using traditional FRTS commands. Using different methods to define FRTS for different routers can introduce inconsistency and complexity when FRTS is being implemented on different router platforms.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    class-map class-map-name

4.    match match-criteria

5.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	class-map class-map-name Example: Router(config)# class-map voice	Creates a class map to be used for matching packets to a specified class and enters class-map configuration mode. The example command creates a class map named "voice".
Step 4	match match-criteria Example: Router(config-cmap)# match ip dscp ef	Identifies packets that will belong to the class map. The example command identifies an IP differentiated service code point (DSCP) value of EF (101110) as a match criterion for the class map named "voice".
Step 5	end Example: Router(config-cmap)# end	(Optional) Exits class-map configuration mode and returns to privileged EXEC mode.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    policy-map policy-map-name

4.    class name

5.    priority [bandwidth-kbps | percent percentage] [burst

6.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	policy-map policy-map-name Example: Router(config)# policy-map llq	Creates a policy map that can be attached to one or more interfaces to specify a service policy and enters policy-map configuration mode. The example command creates a policy map named "llq". This policy map will be used for low latency queueing (LLQ).
Step 4	class name Example: Router(config-pmap)# class voice	Specifies the name of the class whose policy you want to create and enters policy-map class configuration mode. The example command creates a traffic class named "voice".
Step 5	priority [bandwidth-kbps | percent percentage] [burst Example: Router(config-pmap-c)# priority 32	(Optional) Gives priority to a class of traffic belonging to a policy map. The example command provides a guaranteed allowed bandwidth of 32 kbps and a guaranteed low latency for up to 32 kbps to the traffic class "voice" that was created in Step 4 .
Step 6	end Example: Router(config-pmap-c)# end	(Optional) Exits policy-map class configuration mode and returns to privileged EXEC mode.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    policy-map policy-map-name

4.    class class-default

5.    shape {average | peak} {mean-rate [burst-size [excess-burst-size]] | percent percentage [burst-size ms [excess-burst [ms]]]}

6.    shape adaptive mean-rate-lower-bound

7.    shape fecn-adapt

8.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	policy-map policy-map-name Example: Router(config)# policy-map shape-policy-map	Creates a policy map that can be attached to one or more interfaces to specify a service policy and enters policy-map configuration mode. The example command creates a policy map named shape-policy-map.
Step 4	class class-default Example: Router(config-pmap)# class class-default	Specifies the default class (commonly known as the class-default class) before you configure its policy and enters policy-map class configuration mode. The class-default class is the class to which traffic is directed if that traffic does not satisfy the match criteria of other classes whose policy is defined in the policy map. Only one class is defined with this command (the class-default class); therefore, it will match all traffic.
Step 5	shape {average | peak} {mean-rate [burst-size [excess-burst-size]] | percent percentage [burst-size ms [excess-burst [ms]]]} Example: Router(config-pmap-c)# shape average 64000	Shapes traffic to the indicated bit rate according to the algorithm specified. The example command configures a shape entity with a CIR of 64,000 bytes per second (bps). Any FRTS commands supported by this feature can be used for traffic shaping. Refer to the Restrictions for MQC-Based Frame Relay Traffic Shaping section for a list of supported FRTS commands.
Step 6	shape adaptive mean-rate-lower-bound Example: Router(config-pmap-c)# shape adaptive 32000	(Optional) Configures a Frame Relay PVC to estimate the available bandwidth by backward explicit congestion notification (BECN) integration while traffic shaping is enabled. The example command sets the lower bound CIR to 32,000 bps when BECNs are received.
Step 7	shape fecn-adapt Example: Router(config-pmap-c)# shape fecn-adapt	(Optional) Configures a Frame Relay interface to reflect received forward explicit congestion notification (FECN) bits as BECN bits in Q.922 "Test Response" messages. The example command adapts the Frame Relay message with FECN to BECN.
Step 8	end Example: Router(config-pmap-c)# end	(Optional) Exits policy-map class configuration mode and returns to privileged EXEC mode.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    policy-map policy-map-name

4.    class class-default

5.    service-policy policy-map-name

6.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	policy-map policy-map-name Example: Router(config)# policy-map shape-policy-map	Creates a policy map that can be attached to one or more interfaces to specify a service policy and enters policy-map configuration mode. The example command creates a policy map named shape-policy-map.
Step 4	class class-default Example: Router(config-pmap)# class class-default	Specifies the default class (commonly known as the class-default class) before you configure its policy and enters policy-map class configuration mode. The class-default class is the class to which traffic is directed if that traffic does not satisfy the match criteria of other classes whose policy is defined in the policy map. Only one class is defined with this command (the class-default class); therefore, it will match all traffic.
Step 5	service-policy policy-map-name Example: Router(config-pmap-c)# service-policy llq	Attaches a service policy as a traffic shaping policy within a policy map. This parent-child service policy association is called a hierarchical service policy. The example command creates a hierarchical service policy with the parent policy map being "shape-policy-map", and the child policy map being "llq".
Step 6	end Example: Router(config-pmap-c)# end	(Optional) Exits policy-map class configuration mode and returns to privileged EXEC mode.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    map-class frame-relay map-class-name

4.    service-policy {input | output} policy-map-name

5.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	map-class frame-relay map-class-name Example: Router (config)# map-class frame-relay shape-map-class	Specifies a map class to define fragmentation values for both a PVC and a MQC policy map attachment and enters static maps class configuration mode. The example command specifies a map class named shape-map-class.
Step 4	service-policy {input | output} policy-map-name Example: Router(config-map-class)# service-policy input shape-policy-map	Attaches a service policy for a PVC.
Step 5	end Example: Router(config-map-class)# end	(Optional) Exits static maps class configuration mode and returns to privileged EXEC mode.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number [name-tag]

4.    encapsulation frame-relay [MFR | ietf]

5.    exit

6.    interface type slot / port . subinterface-number [multipoint | point-to-point]

7.    ip address ip-address mask [secondary]

8.    frame-relay interface-dlci dlci [ietf | cisco]

9.    class name

10.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	interface type number [name-tag] Example: Router(config)# interface serial 0/0	Configures an interface type and enters interface configuration mode.
Step 4	encapsulation frame-relay [MFR | ietf] Example: Router(config-if)# encapsulation frame-relay	Enables Frame Relay encapsulation.
Step 5	exit Example: Router(config-if)# exit	Exits interface configuration mode and returns to global configuration mode.
Step 6	interface type slot / port . subinterface-number [multipoint | point-to-point] Example: Router(config)# interface serial 0/0.1 point-to-point	Configures a subinterface and enters subinterface configuration mode.
Step 7	ip address ip-address mask [secondary] Example: Router(config-subif)# ip address 192.168.1.1 255.255.255.0	Sets the primary IP address and mask for the subinterface.
Step 8	frame-relay interface-dlci dlci [ietf | cisco] Example: Router(config-subif)# frame-relay interface-dlci 100	Assigns a data-link connection identifier (DLCI) to a specified Frame Relay subinterface on the router and enters Frame Relay DLCI configuration mode. The example command creates a PVC with a DLCI number of 100 under serial 0/0.1 subinterface.
Step 9	class name Example: Router(config-fr-dlci)# class shape-map-class	Associates a map class with the subinterface. The example command associates the map class named shape-map-class with the PVC created in Step 8 .
Step 10	end Example: Router(config-fr-dlci)# end	(Optional) Exits Frame Relay DLCI configuration mode and returns to privileged EXEC mode.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    map-class frame-relay map-class-name

4.    frame-relay fragment fragment-size [switched]

5.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	map-class frame-relay map-class-name Example: Router (config)# map-class frame-relay shape-map-class	Specifies a map class to define fragmentation parameters for both a PVC and an MQC policy map attachment and enters static map class configuration mode. The example command specifies a map class named shape-map-class.
Step 4	frame-relay fragment fragment-size [switched] Example: Router(config-map-class)# frame-relay fragment 80	(Optional) Enables fragmentation of Frame Relay frames for a Frame Relay map class. The example command specifies that 80 payload bytes from the original Frame Relay frame will go into each fragment.
Step 5	end Example: Router(config-map-class)# end	(Optional) Exits static maps class configuration mode and returns to privileged EXEC mode.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    policy-map policy-map-name

4.    class class-default

5.    service-policy policy-map

6.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	policy-map policy-map-name Example: Router(config)# policy-map shape-policy-map	Creates a policy map that can be attached to one or more interfaces to specify a service policy and enters policy-map configuration mode. The example command creates a policy map named shape-policy-map.
Step 4	class class-default Example: Router(config-pmap)# class class-default	Specifies the default class (commonly known as the class-default class) before you configure its policy and enters policy-map class configuration mode. The class-default class is the class to which traffic is directed if that traffic does not satisfy the match criteria of other classes whose policy is defined in the policy map. Only one class is defined with this command (the class-default class); therefore, it will match all traffic.
Step 5	service-policy policy-map Example: Router(config-pmap-c)# service-policy shape-policy-map	Adds a policy map to a map class and enters policy-map class configuration mode. The example command attaches the policy map named shape-policy-map. This command will also attach the policy map shape to any other PVCs that are using the map class.
Step 6	end Example: Router(config-pmap-c)# end	(Optional) Exits policy-map class configuration mode and returns to privileged EXEC mode.

The following example provides a sample configuration for Class-Based Weighted Fair Queueing (CBWFQ) with FRTS:

class-map voice
 match ip dscp ef
policy-map llq
 class voice
  priority 32
policy-map shape-policy-map
 class class-default
  shape average 64000
  shape adaptive 32000
  service-policy llq
map-class frame-relay shape-map-class
 
service-policy output shape-policy-map
interface serial 0/0
encapsulation frame-relay
interface serial 0/0.1 point-to-point
ip address 192.168.1.1 255.255.255.0
frame-relay interface-dlci 100
class shape-map-class

The following example provides a sample configuration for CBWFQ and fragmentation with FRTS. This configuration example is exactly the same as the example shown in the Example Configuring Class-Based Weighted Fair Queueing section, with the addition of the frame-relay fragment command to configure fragmentation.

class-map voice
 match ip dscp ef
policy-map llq
 class voice
  priority 32
policy-map shape-policy-map
 class class-default
  shape average 64000
  shape adaptive 32000
  service-policy llq
map-class frame-relay shape-map-class
 frame-relay fragment 80
 service-policy output shape-policy-map
interface serial 0/0
 encapsulation frame-relay
interface serial 0/0.1 point-to-point
 ip address 192.168.1.1 255.255.255.0
 frame-relay interface-dlci 100
  class shape-map-class