Frame Relay PVC Bundles with QoS Support for IP and MPLS

Last Updated: December 2, 2012

Frame Relay permanent virtual circuit (PVC) bundle functionality allows you to associate a group of Frame Relay PVCs with a single next-hop address. When Frame Relay PVC bundles are used with IP, packets are mapped to specific PVCs in the bundle on the basis of the precedence value or differentiated services code point (DSCP) settings in the type of service (ToS) field of the IP header. Each packet is treated differently according to the QoS configured for each PVC.

MPLS QoS support for Frame Relay PVC bundles extends Frame Relay PVC bundle functionality to support the mapping of Multiprotocol Label Switching (MPLS) packets to specific PVCs in the bundle. MPLS packets are mapped to PVCs according to the settings of the experimental (EXP) bits in the MPLS packet header.

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Prerequisites for Frame Relay PVC Bundles with QoS Support for IP and MPLS

To implement Frame Relay PVC bundles between two routers, you must enable IP Cisco Express Forwarding switching on the routers.

To configure MPLS EXP levels on bundle member PVCs, you must have tag-switching enabled on the interface.

It is recommended (but not required) that you implement PVC Interface Priority Queueing (PIPQ) in conjunction with Frame Relay PVC bundles. This will ensure that if the interface becomes congested, higher-priority traffic can exit the interface ahead of lower-priority traffic.

Restrictions for Frame Relay PVC Bundles with QoS Support for IP and MPLS

  • A PVC can be a part of one and only one PVC bundle.
  • A PVC bundle may contain no more than eight PVCs.
  • A PVC that is a bundle member cannot be used in any other capacity, For example a PVC bundle member cannot be configured in a map statement.
  • A PVC bundle cannot perform precedence and DSCP matching at the same time. If the wrong matching scheme is configured, unpredictable behavior will result.
  • A PVC bundle will not come up unless all the precedence, DSCP, or EXP levels are configured in the bundle.
  • Voice over Frame Relay (VoFR) is not supported on PVC-bundle members.
  • Fast switching over Frame Relay PVC bundles is not supported.

Information About Frame Relay PVC Bundles with QoS Support for IP and MPLS

Benefits of Frame Relay PVC Bundles with QoS Support for IP and MPLS

  • IP or MPLS packets carrying different types of traffic can be transported on different PVCs within the same PVC bundle.
  • Precedence-based PVC bundles can be converted to EXP-based PVC bundles by enabling tag-switching. EXP-based PVC bundles can be converted to precedence-based PVC bundles by disabling tag-switching.
  • This feature provides flexible PVC management within a PVC bundle by allowing traffic assigned to a failed PVC to be redirected to an alternate PVC within the bundle. This feature also allows you to configure the bundle to go down when certain PVCs go down.

Frame Relay PVC Bundle Support

The use of Frame Relay PVC bundles allows you to configure multiple PVCs with different QoS characteristics between any pair of Frame Relay-connected routers. As shown in the figure below, a PVC bundle may contain up to eight PVCs. The individual PVCs within a bundle are called bundle members .

To determine which PVC in a bundle will be used to forward a specific type of traffic, the router maps the IP precedence level or DSCP value in an IPv4 packet header to a PVC configured with the same value. In the case of MPLS, packets are mapped to specific PVCs in a bundle based on the settings of the EXP bits in the MPLS packet headers.

Once you define a Frame Relay bundle and add PVCs to it, you can configure attributes and characteristics to discrete PVC bundle members, or you can apply them collectively at the bundle level. Frame Relay traffic shaping may be applied to every PVC within a bundle. As with individual PVCs, you can enable rate adaptation to occur in response to incoming backward explicit congestion notifications (BECN) from the network.

Figure 1 Frame Relay PVC bundle


You can create differentiated service using PVC bundles by distributing IP precedence levels or DSCP values over the various bundle members. You can map either a single precedence level or a range of precedence levels to each PVC in the bundle. Thus, either you can limit an individual PVC to carry only packets marked with a specific precedence level or you can enable a PVC to carry packets marked with different precedence levels.

Service Levels and PVC Selection Criteria

The DSCP and Precedence bits classify IP packet service levels. The Precedence field consists of the first three bits of the ToS octet in the IPv4 header. These bits define eight precedence levels. When DSCP mapping is used, the DSCP octet replaces the ToS octet in the IPv4 header. Currently the first six bits are used, defining 64 service levels.

Using precedence-based or DSCP-based mapping, each IPv4 packet is mapped to a specific PVC in the bundle, according to the value of the ToS or DSCP octet in the IP header. There is no special treatment for broadcast or multicast or IP routing packets; the only differentiation in treatment is a result of the ToS or DSCP octet settings.

The MPLS EXP bits make up a three-bit experimental field in the MPLS packet header. They are a bit-by-bit copy of the IP Precedence bits and provide the same eight QoS levels. Under MPLS EXP-based mapping, each MPLS packet is mapped to a specific PVC in the bundle, according the setting of the EXP bits.

Frame Relay PVC Bundle Management

In addition to mapping specific traffic types to specific PVCs according to QoS parameters designated by the ToS or DSCP values in the IPv4 headers or EXP values in the MPLS headers, PVC bundle management takes care of handling non-IP traffic and determining what happens if a PVC goes down.

By default, Inverse Address Resolution Protocol (ARP) traffic and other critical non-IP traffic is carried by the PVC configured for carrying IP Precedence or EXP level 6 or DSCP level 63. You can select a PVC with a different QoS to carry Inverse ARP traffic if required. Noncritical non-IP traffic is carried by the PVC that configured for carrying IP precedence, EXP, or DSCP level 0.

It is important during configuration to account for every precedence, EXP, or DSCP level in the configuration of the PVC bundle members. If all the packet service levels are not accounted for, the PVC bundle will never come up.

Once a PVC bundle is up, if an individual bundle member goes down, an attempt is made to identify an alternate PVC to handle the packet service level or levels that were carried by the downed PVC. If no alternate PVC is found, the entire PVC bundle is brought down.

Traffic Bumping

You can configure each PVC bundle member to bump traffic to another PVC in the bundle in the event that the bundle member goes down. You can specify whether the bumping will be implicit or explicit bumping. You can also specify that a particular PVC will never accept bumped traffic from another PVC. The default conditions are to perform implicit traffic bumping and to accept bumped traffic.

Implicit bumping diverts the traffic from a failed PVC to the PVC having the next-lower service level. Explicit bumping forces the traffic to a specific PVC rather than allowing it to find a PVC carrying traffic of the next-lower service level. For example, PVC x , responsible for carrying precedence level 3 traffic, can be configured to bump its traffic to PVC y , responsible for carrying precedence level 6 traffic--provided that PVC y is configured to accept bumped traffic. If PVC x goes down, PVC y takes over. If PVC y is already down or goes down later, the alternate PVC selected will depend on the bumping rule for PVC y . If no alternate PVC can be found for bumped traffic, the entire PVC bundle goes down.

PVC-Bundle Protection Rules

Traffic bumping provides a way to keep a PVC bundle up and traffic flowing even though some individual PVCs may be down. Protection rules provide a way to force the PVC bundle down even though some individual PVCs are up and might be able to handle all the traffic, though perhaps not in a satisfactory manner.

You can configure a PVC bundle member as an individually protected PVC or as part of a PVC bundle protected group. Only one protected group may exist within a PVC bundle; however, many individually protected PVCs may exist. The protection rules add flexibility for controlling the PVC bundle state.

When any one individually protected PVC goes down, the entire bundle goes down. If all the PVCs in a protected group go down, the entire bundle goes down.

If no protection rule is specified, the PVC bundle goes down only when all the PVCs go down. However, protection is overridden if a PVC that has no place to bump its traffic goes down. In this case, the entire bundle will go down despite any protection rules that have been set up.

MPLS EXP-based Mapping

To enable MPLS EXP-based mapping, tag-switching must be enabled on the interface or subinterface by using the tag-switching ip command. When tag-switching is enabled, MPLS and IP packets can flow across the interface and PVC bundles that are configured for IP Precedence mapping are converted to MPLS EXP mapping. The PVC bundle functionality remains the same with respect to priority levels, bumping, and so on, but the match precedence command is replaced by match exp, and each precedence command is replaced by the exp command. The effect is that a bundle member PVC previously configured to carry precedence level 1 IP traffic now carries EXP level 1 MPLS traffic.

PVC bundles configured for DSCP mapping go down when tag-switching is enabled. The DSCP configuration for each bundle member PVC is reset, resulting in the PVCs being unmapped and Inverse ARP, bumping, and protection settings being unconfigured. The match dscp command is replaced by match expcommand.

When tag-switching is disabled, the match precedenceand match dscpcommands are restored and the exp commands are replaced by precedence commands.

When tag-switching is enabled or disabled, PVC bundles configured for IP precedence mapping or MPLS EXP mapping will stay up and traffic will transmit over the appropriate bundle member PVCs.

How to Configure Frame Relay PVC Bundles with QoS Support for IP and MPLS

Configuring Frame Relay PVC Bundles with IP QoS Support

To configure Frame Relay PVC bundles for handling IP packets, perform the following steps:

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ip routing

4.    ip cef

5.   Do one of the following:

  • interface type number
  • interface type number . subinterface-number
  • multipoint | point-to-point]

6.    encapsulation frame-relay [cisco |ietf]

7.    ip address ip-address mask [secondary]

8.    frame-relay map protocol protocol-address {dlci| vc-bundle vc-bundle-name} [broadcast] [ietf| cisco]

9.    frame-relay vc-bundle vc-bundle-name

10.    encapsulation [cisco | ietf]

11.    match {dscp dscp-value| precedence precedence-value}

12.    pvc dlci [vc-name]

13.    class name

14.   Do one of the following:

  • precedence {level | other}
  • dscp {level | other}

15.    bump {explicit level | implicit | traffic}

16.    protect {group | vc}

17.    inarp

18.    end

19.    Configure the PVC bundle on the peer router.


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
ip routing


Example:

Router(config)# ip routing

 

Enables IP routing.

 
Step 4
ip cef


Example:

Router(config)# ip cef

 

Enables Cisco Express Forwarding.

Note    For the Cisco 7500, enter ip cef distributed.
 
Step 5
Do one of the following:
  • interface type number
  • interface type number . subinterface-number
  • multipoint | point-to-point]


Example:

Router(config)# interface serial 0



Example:



Example:



Example:

Router(config)# interface serial 1.1 multipoint

 

Specifies the interface type and number and enters interface configuration mode.

  • Physical interfaces are multipoint subinterfaces by default.

or

Specifies the interface type and subinterface and enters subinterface configuration mode.

  • Once you create a specific type of subinterface (point-to-point or multipoint), you cannot change it without a reload. To change it, you must either reload the router or create another subinterface.
 
Step 6
encapsulation frame-relay [cisco |ietf]


Example:

Router(config-if)# encapsulation frame-relay

 

Enables Frame Relay encapsulation.

  • The default encapsulation method is cisco.
 
Step 7
ip address ip-address mask [secondary]


Example:

Router(config-if)# ip address 10.1.1.1 255.0.0.0

 

Sets a primary IP address for the interface.

  • The optional secondary keyword specifies that the configured address is a secondary IP address. If this keyword is omitted, the configured address is the primary IP address.
 
Step 8
frame-relay map protocol protocol-address {dlci| vc-bundle vc-bundle-name} [broadcast] [ietf| cisco]


Example:

Router(config-if)# frame-relay map ip 10.2.2.2 vc-bundle MAIN-1

 

(Optional) Maps between a next-hop protocol address and a data-link connection identifier (DLCI) destination address, and creates a PVC bundle if it does not already exist.

  • The protocol-address is the destination IP address.
  • The frame-relay map command is required for multipoint interfaces if Inverse ARP has been disabled or is not supported at the other end of the connection.
 
Step 9
frame-relay vc-bundle vc-bundle-name


Example:

Router(config-if)# frame-relay vc-bundle MAIN-1

 

Creates a PVC bundle if it does not already exist, and enters Frame Relay VC-bundle configuration mode.

 
Step 10
encapsulation [cisco | ietf]


Example:

Router(config-fr-vcb)# encapsulation ietf

 

(Optional) Overrides the encapsulation type configured on the interface and configures the Frame Relay encapsulation type for the PVC bundle.

  • This command is available only when the PVC bundle is configured on a point-to-point subinterface.
 
Step 11
match {dscp dscp-value| precedence precedence-value}


Example:

Router(config-fr-vcb)# match precedence 5

 

Establishes the type of matching to use between incoming packet headers and PVC-bundle members.

  • The default match type is precedence.
 
Step 12
pvc dlci [vc-name]


Example:

Router(config-fr-vcb)# pvc 100 1a

 

Creates a PVC-bundle member and enters Frame Relay VC-bundle-member configuration mode.

  • The vc-name argument is an optional name that can be used for referring to the PVC.
 
Step 13
class name


Example:

Router(config-fr-vcb-vc)# class premium

 

(Optional) Assigns a map class to the PVC-bundle member defined in the previous step.

 
Step 14
Do one of the following:
  • precedence {level | other}
  • dscp {level | other}


Example:

Router(config-fr-vcb-vc)# precedence 6-7



Example:



Example:



Example:

Router(config-fr-vcb-vc)# dscp other

 

(Optional) Enters the mapped service level or range for the PVC-bundle member.

  • The precedence command is available when the PVC-bundle match type is set to precedence.
  • The precedence range is from 0 to 7.
  • The dscp command is available when the PVC-bundle match type is set to dscp.
  • The dscp range is from 0 to 63.
  • The other keyword is used to designate a PVC to handle all the remaining levels that have not been assigned to other PVCs in the bundle.
  • Critical non-IP traffic will automatically use precedence level 0.
 
Step 15
bump {explicit level | implicit | traffic}


Example:

Router(config-fr-vcb-vc)# bump explicit 7

 

(Optional) Specifies the bumping rule for the PVC-bundle member.

  • The default bumping rule is implicit bumping.
  • Use the explicit level option to specify the service level to which traffic on this PVC will be bumped if the PVC goes down. In that event, the traffic will be directed to a PVC mapped with the service level configured here. If the PVC that picks up and carries the traffic also goes down, the traffic is subject to the bumping rules for that PVC. You can specify only one service level for bumping.
  • The PVC-bundle member accepts bumped traffic by default when the PVC-bundle match type is precedence. To configure the PVC to reject bumped traffic from another PVC-bundle member, use the no bump traffic command.
 
Step 16
protect {group | vc}


Example:

Router(config-fr-vcb-vc)# protect group

 

(Optional) Specifies the protection rule for the PVC-bundle member.

  • By default, the PVC-bundle member is not protected.
  • If you use the vc keyword, the PVC bundle goes down whenever this PVC goes down.
  • If you use the group keyword, the PVC bundle goes down when the last PVC in the protected group goes down.
 
Step 17
inarp


Example:

Router(config-fr-vcb-vc)# inarp

 

(Optional) Enables Inverse ARP for the PVC-bundle member.

  • By default, Inverse ARP traffic uses the PVC configured for precedence level 6 or DSCP level 63.
 
Step 18
end


Example:

Router(config-fr-vcb-vc)# end

 

Exits to privileged EXEC mode.

 
Step 19
Configure the PVC bundle on the peer router. 

(Optional) While it is not necessary to configure a PVC bundle on the peer router, it is recommended that you do so for applications that rely on communications on the same PVC (such as TCP header-compression.)

 

Configuring Frame Relay PVC Bundles with MPLS QoS Support

To configure Frame Relay PVC bundles for handling MPLS packets, perform the following steps:

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ip routing

4.    ip cef

5.   Do one of the following:

  • interface type number
  • interface {type slot | port-adapter | port.subinterface-number} [multipoint | point-to-point]

6.    encapsulation frame-relay [cisco | ietf]

7.    tag-switching ip

8.    ip address ip-address mask [secondary]

9.    frame-relay map protocol protocol-address {dlci| vc-bundle vc-bundle-name} [broadcast] [ietf| cisco]

10.    frame-relay vc-bundle vc-bundle-name

11.    encapsulation [ietf | cisco]

12.    pvc dlci [vc-name]

13.    class name

14.    exp {level | other}

15.    bump {explicit level | implicit | traffic}

16.    protect {group | vc}

17.    inarp

18.    end

19.    Configure the PVC bundle on the peer router.


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
ip routing


Example:

Router(config)# ip routing

 

Enables IP routing.

 
Step 4
ip cef


Example:

Router(config)# ip cef

 

Enables Cisco Express Forwarding.

Note    For the Cisco 7500, enter ip cef distributed.
 
Step 5
Do one of the following:
  • interface type number
  • interface {type slot | port-adapter | port.subinterface-number} [multipoint | point-to-point]


Example:

Router(config)# interface serial 0



Example:



Example:



Example:



Example:

Router(config)# interface serial 1.1 multipoint

 

Specifies the interface type and number and enters interface configuration mode.

  • Physical interfaces are multipoint subinterfaces by default.

or

Specifies the interface type and subinterface and enters subinterface configuration mode.

  • Once you create a specific type of subinterface (point-to-point or multipoint), you cannot change it without a reload. To change it, you need to either reload the router or create another subinterface.
 
Step 6
encapsulation frame-relay [cisco | ietf]


Example:

Router(config-if)# encapsulation frame-relay

 

Enables Frame Relay encapsulation.

  • The default encapsulation method is cisco.
 
Step 7
tag-switching ip


Example:

Router(config-if)# tag-switching ip

 

Enables label switching of IPv4 packets on an interface.

 
Step 8
ip address ip-address mask [secondary]


Example:

Router(config-if)# ip address 10.1.1.1 255.0.0.0

 

Sets a primary IP address for the interface.

  • The optional secondary keyword specifies that the configured address is a secondary IP address. If this keyword is omitted, the configured address is the primary IP address.
 
Step 9
frame-relay map protocol protocol-address {dlci| vc-bundle vc-bundle-name} [broadcast] [ietf| cisco]


Example:

Router(config-if)# frame-relay map ip 10.2.2.2 vc-bundle MAIN-1

 

(Optional) Maps between a next-hop protocol address and a DLCI destination address, and creates a PVC bundle if it does not already exist.

  • The protocol-address is the destination IP address.
  • The frame-relay map command is required for multipoint interfaces if Inverse ARP has been disabled or is not supported at the other end of the connection.
 
Step 10
frame-relay vc-bundle vc-bundle-name


Example:

Router(config-if)# frame-relay vc-bundle MAIN-1

 

Creates a PVC bundle if it does not already exist, and enters Frame Relay VC-bundle configuration mode.

 
Step 11
encapsulation [ietf | cisco]


Example:

Router(config-fr-vcb)# encapsulation ietf

 

(Optional) Overrides the encapsulation type configured on the interface and configures the Frame Relay encapsulation type for the PVC bundle.

  • This command is available only when the PVC bundle is configured on a point-to-point subinterface.
 
Step 12
pvc dlci [vc-name]


Example:

Router(config-fr-vcb)# pvc 100 1a

 

Creates a PVC-bundle member and enters Frame Relay VC-bundle-member configuration mode.

  • The vc-name argument is an optional name that can be used for referring to the PVC.
 
Step 13
class name


Example:

Router(config-fr-vcb-vc)# class premium

 

(Optional) Assigns a map class to the PVC-bundle member.

 
Step 14
exp {level | other}


Example:

Router(config-fr-vcb-vc)# exp 6-7

 

(Optional) Enters the mapped EXP level or range for the PVC-bundle member.

  • The exp command is available only when tag-switching has been enabled.
  • The EXP level values are from 0 to 7.
  • The other keyword is used to designate a PVC to handle all the remaining levels that have not been assigned to other PVCs in the bundle.
 
Step 15
bump {explicit level | implicit | traffic}


Example:

Router(config-fr-vcb-vc)# bump explicit 7

 

(Optional) Specifies the bumping rule for the PVC-bundle member defined above.

  • The default bumping rule is implicit bumping.
  • Use the explicit level option to specify the EXP level to which traffic on this PVC will be bumped if the PVC goes down. In that event, the traffic will be directed to a PVC mapped with the EXP level configured here. If the PVC that picks up and carries the traffic also goes down, the traffic is subject to the bumping rules for that PVC. You can specify only one EXP level for bumping.
  • To configure the PVC to reject bumped traffic from another PVC-bundle member, use the no bump traffic command.
 
Step 16
protect {group | vc}


Example:

Router(config-fr-vcb-vc)# protect group

 

(Optional) Specifies the protection rule for the PVC-bundle member defined above.

  • By default, the PVC-bundle member is not protected.
  • If you use the vc keyword, the PVC bundle goes down whenever this PVC goes down.
  • If you use the group keyword, the PVC bundle goes down when the last PVC in the protected group goes down.
 
Step 17
inarp


Example:

Router(config-fr-vcb-vc)# inarp

 

(Optional) Enables Inverse ARP for the PVC-bundle member defined above.

  • By default, Inverse ARP traffic uses the PVC configured for EXP level 6.
 
Step 18
end


Example:

Router(config-fr-vcb-vc)# end

 

(Optional) Exits to privileged EXEC mode.

 
Step 19
Configure the PVC bundle on the peer router. 

(Optional) While it is not necessary to configure a PVC bundle on the peer router, it is recommended that you do so for applications that rely on communications on the same PVC (such as TCP header-compression.)

 

Verifying Frame Relay PVC Bundles Configuration

To verify the configuration and operation of Frame Relay PVC bundles with QoS support, perform the following optional steps:

SUMMARY STEPS

1.    enable

2.    show frame-relay vc-bundle vc-bundle-name [detail

3.    show frame-relay map

4.    show frame-relay pvc

5.    show frame-relay ip rtp header-compression [interface type number]

6.    show frame-relay ip tcp header-compression [interface type number]

7.    show adjacency [type number] [detail] [summary]


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
show frame-relay vc-bundle vc-bundle-name [detail


Example:

Router# show frame-relay vc-bundle mp-3-static

 

Displays status, bumping information, protection information, and active and configured precedence or DSCP levels for the PVCs in a PVC bundle.

 
Step 3
show frame-relay map


Example:

Router# show frame-relay map

 

Displays the current Frame Relay map entries and information about the connections.

 
Step 4
show frame-relay pvc


Example:

Router# show frame-relay pvc

 

Displays PVC statistics for the PVC-bundle members.

 
Step 5
show frame-relay ip rtp header-compression [interface type number]


Example:

Router# show frame-relay ip rtp header-compression

 

Displays Frame Relay Real-Time Transport Protocol (RTP) header compression statistics for PVC bundles.

 
Step 6
show frame-relay ip tcp header-compression [interface type number]


Example:

Router# show frame-relay ip tcp header-compression serial 1/4

 

Displays Frame Relay TCP/IP header compression statistics for PVC bundles.

 
Step 7
show adjacency [type number] [detail] [summary]


Example:

Router# show adjacency

 

Displays Cisco Express Forwarding adjacency table information.

 

Monitoring and Maintaining Frame Relay PVC Bundles

To monitor and maintain Frame Relay PVC bundles, perform this task.

SUMMARY STEPS

1.    enable

2.    debug frame-relay adjacency {pvc[dlci] | vc-bundle [vc-bundle-name]}

3.    debug frame-relay vc-bundle {detail | state-change} [vc-bundle-name]


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Router> enable

 

Enables higher privilege levels, such as privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
debug frame-relay adjacency {pvc[dlci] | vc-bundle [vc-bundle-name]}


Example:

Router# debug frame-relay adjacency pvc

 

Displays information pertaining to an adjacent node that has one or more Frame Relay PVCs or PVC bundles.

  • Use this command to monitor adjacency activity.
 
Step 3
debug frame-relay vc-bundle {detail | state-change} [vc-bundle-name]


Example:

Router# debug frame-relay vc-bundle state-change

 

Displays information about the Frame Relay PVC bundles configured on a router.

  • Use this command to monitor state changes and Inverse ARP activity for one or all of the PVC bundles and bundle members configured on a router.
Note    Using the detail keyword generates a large number of debugs that can quickly fill up a log buffer.
 

Configuration Examples for Frame Relay PVC Bundles with QoS Support for IP and MPLS

PVC Bundles with IP QoS Support on Interfaces Example

The following example shows the configuration of five PVC bundles with IP precedence and DSCP mapping. Two bundles are configured on the main interface, one bundle with static mapping and one with dynamic mapping. Two bundles are configured on a multipoint subinterface, one bundle with static mapping and one with dynamic mapping. One bundle is configured on a point-to-point subinterface.

configure terminal 
ip routing 
ip cef 
interface Serial 1/4 
 encapsulation frame-relay 
 frame-relay intf-type dte 
 ip address 10.1.1.1 255.0.0.0 
 frame-relay map ip 192.168.2.2 vc-bundle MAIN-1-static 
 frame-relay vc-bundle MAIN-1-static 
 match precedence 
 pvc 100 1a 
 precedence other 
 pvc 101 1b 
 precedence 1 
 pvc 102 1c 
 precedence 2 
 pvc 103 1d 
 precedence 3 
 pvc 104 1e 
 precedence 4 
 pvc 105 1f 
 precedence 5 
 pvc 106 1g 
 precedence 6 
 pvc 107 1h 
 frame-relay vc-bundle MAIN-2-dynamic 
 match precedence 
 pvc 200 
 precedence 0 
 pvc 201 
 precedence 1 
 pvc 202 
 precedence 2 
 pvc 203 
 precedence 3 
 pvc 204 
 precedence 4 
 pvc 205 
 precedence 5 
 pvc 206 
 precedence 6 
 pvc 207 
 precedence 7 
interface Serial 1/4.1 multipoint 
 ip address 172.16.1.1 255.0.0.0 
 frame-relay map ip 172.17.2.2 vc-bundle MP-3-static 
 frame-relay vc-bundle MP-3-static 
  match precedence 
 pvc 300 3a 
 precedence 0 
 pvc 301 3b 
 precedence 1 
 pvc 302 3c 
 precedence 2 
 pvc 303 3d 
 precedence 3 
 pvc 304 3e 
 precedence 4 
 pvc 305 3f 
 precedence 5 
 pvc 306 3g 
 precedence 6 
 pvc 307 3h 
 precedence 7 
interface Serial 1/4.1 multipoint 
 frame-relay vc-bundle MP-4-dynamic 
 match precedence 
 match dscp 
 pvc 400 4a 
 dscp other 
 pvc 401 4b 
 dscp 10-19 
 pvc 402 4c 
 dscp 20-29 
 pvc 403 4d 
 dscp 30-39 
 pvc 404 4e 
 dscp 40-49 
 pvc 405 4f 
 dscp 50-59 
 pvc 406 4g 
 dscp 60-62 
 pvc 407 4h 
 dscp 63 
 end 
interface Serial 1/4.2 point-to-point 
 ip address 192.168.2.1 255.0.0.0 
 frame-relay vc-bundle P2P-5 
 match precedence 
 pvc 500 5a 
 precedence 0 
 pvc 501 5b 
 precedence 1 
 pvc 502 5c 
 precedence 2 
 pvc 503 5d 
 precedence 3 
 pvc 504 5e 
 precedence 4 
 pvc 505 5f 
 precedence 5 
 pvc 506 5g 
 precedence 6 
 pvc 507 5h 
 precedence 7

PVC Bundle with IP QoS Support with Multiple QoS Parameters Example

The following example shows the configuration of a Frame Relay PVC bundle with DSCP-based mapping. The bundle member PVCs are configured with bumping, protection, and other parameters.

interface Serial 1/4.2 point-to-point
 frame-relay vc-bundle BUNDLE-SEFEN
 encapsulation ietf
 match dscp
  pvc 301
 dscp other
 bump explicit 45
 protect group
 class CIR-64000
 pvc 302
 dscp 40-49
 bump explicit 20
 no bump traffic
 protect vc
 inarp
 pvc 303
 dscp 30-39
 bump implicit
 protect group

PVC Bundle with MPLS QoS Support Example

The following example shows the configuration of four Frame Relay PVC bundle members with MPLS EXP level support in the PVC bundle named "user1".

interface serial 0.1 point-to-point
 encapsulation frame-relay
 ip address 10.1.1.1
 tag-switching ip
 frame-relay vc-bundle user1
 pvc 100 ny-control
 class control
 exp 7
 protect vc
 pvc 101 ny-premium
 class premium
 exp 6-5
 bump explicit 7
 no bump traffic
 protect group
 pvc 102 my-priority
 class priority
 exp 4-2
 protect group
 pvc 103 ny-basic
 class basic
 exp other

protect group

Verifying Frame Relay PVC Bundle Configuration Examples

The following examples show output for the commands that can be used to verify Frame Relay PVC bundle configuration.

Sample Output for the show frame-relay vc-bundle Command

The following example shows the Frame Relay PVC bundle named "MP-4-dynamic" with PVC protection applied. Note that in this PVC bundle, DLCI 400 is configured to bump traffic explicitly to the PVC that handles DSCP level 40, which is DLCI 404. All the other DLCIs are configured for implicit bumping. In addition, all the DLCIs are configured to accept bumped traffic.

The asterisk (*) before PVC 4a indicates that this PVC was configured with the precedence other command, which means the PVC will handle all levels that are not explicitly configured on other PVCs.

In this example all PVCs are up so the values in the "Active level" fields match the values in the "Config level" fields. If a PVC goes down and its traffic is bumped, the "Active level" field value for the PVC that went down is cleared. The "Active level" field values for the PVC that the traffic bumped to will be updated to include the levels of the PVC that went down.

The first three PVCs in the following example make up a protected group. All three of these PVCs must go down before the bundle will go down. The last two PVCs are protected PVCs: if either of these PVCs go down, the bundle will go down. 

Router# show frame-relay vc-bundle MP-4-dynamic
MP-4-dynamic on Serial 1/4.1 - Status: UP Match-type: DSCP
Name 		DLCI 		Config. 	Active 				Bumping 			PG/ 		CIR 		Status 
				level 		level 			to/accept 			PV 		kbps
*4a 		400 		0-9 		0-9 			40/Yes 			pg 				up 
4b 		401 		10-19 		10-19 			9/Yes 			pg 				up 
4c 		402 		20-29 		20-29 			19/Yes 			pg 				up 
4d 		403 		30-39 		30-39 			29/Yes 			- 				up 
4e 		404 		40-49 		40-49 			39/Yes 			- 				up 
4f 		405 		50-59 		50-59 			49/Yes 			- 				up 
4g 		406 		60-62 		60-62 			59/Yes 			pv 				up 
4h 		407 		63 		63 			62/Yes 			pv 				up
Packets sent out on vc-bundle MP-4-dynamic : 0:
Router#

The following example shows the detail output of a PVC bundle. Note in this example that because all packet service levels are not handled, and because the PVCs are currently down, this bundle can never come up.

Router# show frame-relay vc-bundle x41 detail
x41 on Serial1/1 - Status: DOWN Match-type: DSCP
Name 		DLCI 		Config. 		Active 			Bumping 			PG/ 		CIR 		Status 
				level 		level 			to/accept 			PV 		kbps
		410 		50-62 					49/Yes 			- 				down 
		411 		30,32,34,36,3.. 					29/Yes 			- 				down
Packets sent out on vc-bundle x41 : 0
Active configuration and statistics for each member PVC
DLCI 		Output pkts 				Active level
410 		0 				50-62 
411 		0 				30,32,34,36,38-40 
Router#

Sample Output for the show frame-relay map Command

The following sample output displays map and connection information for a PVC bundle called "MAIN-1-static":

Router# show frame-relay map
Serial1/4 (up):ip 10.2.2.2 vc-bundle MAIN-1-static, static,
              CISCO, status up

Sample Output for the show frame-relay pvc Command

The following sample output indicates that PVC 202 is a member of VC bundle "MAIN-1-static":

Router# show frame-relay pvc 202
PVC Statistics for interface Serial1/4 (Frame Relay DTE)
DLCI = 202, DLCI USAGE = LOCAL, PVC STATUS = STATIC, INTERFACE = Serial1/4
  input pkts 0             output pkts 45           in bytes 0
  out bytes 45000          dropped pkts 0           in FECN pkts 0
  in BECN pkts 0           out FECN pkts 0          out BECN pkts 0
  in DE pkts 0             out DE pkts 0
  out bcast pkts 0         out bcast bytes 0
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 2000 bits/sec, 2 packets/sec
  pvc create time 00:01:25, last time pvc status changed 00:01:11
  VC-Bundle MAIN-1-static

Sample Output for the show adjacency Command

The following is sample output for the show adjacency command for a PVC bundle configured on serial subinterface 1/4.1. Each bundle member is listed. The bundle itself is indicated by "incomplete" because no traffic actually transmitted on that entry.

Router# show adjacency
      Protocol Interface                 Address
      IP       Serial1/4.1               10.2.2.2(4)
      IP       Serial1/4.1               10.2.2.2(4)
      IP       Serial1/4.1               10.2.2.2(4)
      IP       Serial1/4.1               10.2.2.2(4)
      IP       Serial1/4.1               10.2.2.2(4)
      IP       Serial1/4.1               10.2.2.2(4)
      IP       Serial1/4.1               10.2.2.2(4)
      IP       Serial1/4.1               10.2.2.2(4)
      IP       Serial1/4.1               10.2.2.2(5) (incomplete)

Monitoring and Maintaining Frame Relay PVC Bundles Examples

The following examples show output for the debug frame-relay adjacencyand debug frame-relay vc-bundle commands, which can be used to troubleshoot Frame Relay PVC bundle operation. "FR-VCB" indicates output from the debug frame-relay vc-bundle command, and "FR-ADJ" indicates output from the debug frame-relay adjacencycommand.


Note
Debug messages that are prefixed with "FR_ADJ" (instead of FR-ADJ") or "FR_VCB" (instead of "FR-VCB") indicate serious failures in the Frame Relay PVC bundle performance. Contact the Cisco Technical Assistance Center (TAC) if you see debug messages with these prefixes.

The following is sample output that shows a PVC bundle that uses static map coming up. PVC bundle member 100 comes up first, then the PVC bundle itself can come up. 

Router# debug frame-relay vc-bundle state-change
Router# debug frame-relay adjacency vc-bundle

00:35:58:FR-VCB:MAIN-1-static:member 100 state changed to UP 00:35:58:FR-VCB:MAIN-1-static:state changed to UP 
00:35:58:FR-ADJ:vcb MAIN-1-static:ip 10.2.2.2:adding primary adj  
00:35:58:FR-ADJ:vcb MAIN-1-static:member 100:adding adj 
00:35:58:FR-ADJ:vcb MAIN-1-static:member 100:locking adj at index 0 00:35:58:FR-ADJ:vcb MAIN-1-static:member 100:locking adj at index 1
00:35:58:FR-ADJ:vcb MAIN-1-static:member 100:locking adj at index 2
00:35:58:FR-ADJ:vcb MAIN-1-static:member 100:locking adj at index 3
00:35:58:FR-ADJ:vcb MAIN-1-static:member 100:locking adj at index 4
00:35:58:FR-ADJ:vcb MAIN-1-static:member 100:locking adj at index 5
00:35:58:FR-ADJ:vcb MAIN-1-static:member 100:locking adj at index 6
00:35:58:FR-ADJ:vcb MAIN-1-static:member 100:locking adj at index 7
00:35:58:%FR-5-DLCICHANGE:Interface Serial1/4 - DLCI 100 state changed to ACTIVE 00:35:58:FR-VCB:MAIN-1-static:member 101 state changed to UP 
00:35:58:FR-ADJ:vcb MAIN-1-static:ip 10.2.2.2:updating primary adj 
00:35:58:FR-ADJ:vcb MAIN-1-static:member 100:updating adj 
00:35:58:FR-ADJ:vcb MAIN-1-static:member 101:adding adj 
00:35:58:FR-ADJ:vcb MAIN-1-static:member 100:unlocking adj at index 1 
00:35:58:FR-ADJ:vcb MAIN-1-static:member 101:locking adj at index 1

The following is sample output that shows a PVC bundle going down. Each bundle member PVC is marked for removal from Cisco Express Forwarding adjacency table, and then the adjacency for the PVC bundle itself is marked for removal. The adjacencies are actually removed from the table later when a background clean-up process runs.

00:38:35:FR-VCB:MP-3-static:state changed to DOWN 
00:38:35:FR-ADJ:vcb MP-3-static:ip 172.17.2.2:member 300:removing adj 
00:38:35:FR-ADJ:vcb MP-3-static:ip 172.17.2.2:member 301:removing adj
00:38:35:FR-ADJ:vcb MP-3-static:ip 172.17.2.2:member 302:removing adj
00:38:35:FR-ADJ:vcb MP-3-static:ip 172.17.2.2:member 303:removing adj
00:38:35:FR-ADJ:vcb MP-3-static:ip 172.17.2.2:member 304:removing adj
00:38:35:FR-ADJ:vcb MP-3-static:ip 172.17.2.2:member 305:removing adj
00:38:35:FR-ADJ:vcb MP-3-static:ip 172.17.2.2:removing primary adj

The following is sample output that shows Inverse ARP information for the PVC bundle. PVC bundle member 406 is the only PVC in the bundle to handle Inverse ARP packets. The Inverse ARP packets coming in on other bundle member PVCs are dropped.

00:23:48:FR-VCB:MP-4-dynamic:inarp received on elected member 406 
00:23:48:FR-VCB:MP-4-dynamic:installing dynamic map 
00:23:48:FR-VCB:MP-4-dynamic:dropping inarp received on member 407 
00:23:52:FR-VCB:MP-4-dynamic:sending inarp pkt on member 406

In the following example the PVC bundle goes down because the protected group goes down. All information about active transmission on each PVC is removed.

00:58:27:FR-VCB:MP-4-dynamic:member 402 state changed to DOWN 
00:58:27:FR-VCB:MP-4-dynamic:protected group is DOWN 
00:58:27:FR-VCB:MP-4-dynamic:state changed to DOWN 
00:58:27:FR-VCB:MP-4-dynamic:active table reset

Additional References

Related Documents

Related Topic

Document Title

Frame Relay configuration tasks

"Configuring Frame Relay chapter in the Cisco IOS Wide-Area Networking Configuration Guide , Release 12.2

Frame Relay commands

"Frame Relay Commands chapter in the Cisco IOS Wide-Area Networking Command Reference , Release 12.2

Frame Relay PVC interface priority queueing configuration tasks

"Configuring Weighted Fair Queueing " section in the Congestion Management chapter in the Cisco IOS Quality of Service Configuration Guide , Release 12.2

Standards

Standards

Title

None

--

MIBs

MIBs

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFCs

Title

None

--

Technical Assistance

Description

Link

The Cisco Technical Support & Documentation website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

http://www.cisco.com/techsupport

Feature Information for Frame Relay PVC Bundles with QoS Support for IP and MPLS

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.

Table 1 Feature Information for Frame Relay PVC Bundles with QoS Support for IP and MPLS

Feature Name

Releases

Feature Information

Frame Relay VC Bundling

12.2(13)T 12.2(28)SB 15.0(1)S

Frame Relay permanent virtual circuit (PVC) bundle functionality allows you to associate a group of Frame Relay PVCs with a single next-hop address.

The following commands were introduced or modified: bump (Frame Relay VC-bundle-member), class, debug frame-relay adjacency, debug frame-relay vc-bundle, dscp (Frame Relay VC-bundle-member), encapsulation (Frame Relay VC-bundle), exp, frame-relay inverse-arp, frame-relay map, frame-relay vc-bundle, inarp (Frame Relay VC-bundle-member), match, precedence (Frame Relay VC-bundle-member), protect (Frame Relay VC-bundle-member), pvc (Frame Relay VC-bundle), show frame-relay ip rtp header-compression, show frame-relay ip tcp header-compression, show frame-relay map, show frame-relay pvc, show frame-relay vc-bundle..

Glossary

DLCI --data-link connection identifier. Value that specifies a permanent virtual circuit (PVC) or switched virtual circuit (SVC) in a Frame Relay network.

FIFO queueing -- First-in, first-out queueing. FIFO involves buffering and forwarding of packets in the order of arrival. FIFO embodies no concept of priority or classes of traffic. There is only one queue, and all packets are treated equally. Packets are sent out an interface in the order in which they arrive.

Frame Relay traffic shaping --See FRTS.

FRF.12 --The FRF.12 Implementation Agreement was developed to allow long data frames to be fragmented into smaller pieces and interleaved with real-time frames. In this way, real-time voice and nonreal-time data frames can be carried together on lower-speed links without causing excessive delay to the real-time traffic.

FRTS --Frame Relay traffic shaping. FRTS uses queues on a Frame Relay network to limit surges that can cause congestion. Data is buffered and then sent into the network in regulated amounts to ensure that the traffic will fit within the promised traffic envelope for the particular connection.

PIPQ --Permanent virtual circuit (PVC) interface priority queueing. An interface-level priority queueing scheme in which prioritization is based on destination PVC rather than packet contents.

quality of service --Measure of performance for a transmission system that reflects its transmission quality and service availability.

VoFR --Voice over Frame Relay. Enables a router to carry voice traffic over a Frame Relay network. When voice traffic is sent over Frame Relay, the voice traffic is segmented and encapsulated for transit across the Frame Relay network using FRF.12 encapsulation.

Voice over Frame Relay --See VoFR.

WFQ --weighted fair queueing. 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 among these individual conversations. WFQ is an automatic way of stabilizing network behavior during congestion and results in increased performance and reduced retransmission.

WRED --Weighted Random Early Detection. Combines IP Precedence and standard Random Early Detection (RED) to allow for preferential handling of voice traffic under congestion conditions without exacerbating the congestion. WRED uses and interprets IP Precedence to give priority to voice traffic over data traffic, dropping only data packets.

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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

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