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Table Of Contents
Multilink Frame Relay (FRF.16.1)
Prerequisites for Multilink Frame Relay (FRF.16.1)
Restrictions for Multilink Frame Relay (FRF.16.1)
Information About Multilink Frame Relay (FRF.16.1)
Benefits of Multilink Frame Relay (FRF.16.1)
Link Integrity Protocol Control Messages
Variable Bandwidth Class Support
Load Balancing with Multilink Frame Relay (FRF.16.1)
How to Enable Multilink Frame Relay (FRF.16.1)
Configuring a Multilink Frame Relay Bundle
Configuring a Multilink Frame Relay Bundle Link
Monitoring and Maintaining Multilink Frame Relay (FRF.16.1)
Configuration Examples for Multilink Frame Relay (FRF.16.1)
Configuring Multilink Frame Relay: Example
Configuring Variable Bandwidth Class Support: Example
frame-relay multilink bandwidth-class
frame-relay multilink output-threshold
Multilink Frame Relay (FRF.16.1)
First Published: May 14, 2001Last Updated: May 28, 2008The Multilink Frame Relay (FRF.16.1) feature introduces functionality based on the Frame Relay Forum Multilink Frame Relay UNI/NNI Implementation Agreement (FRF.16.1). This feature provides a cost-effective way to increase bandwidth for particular applications by enabling multiple serial links to be aggregated into a single bundle of bandwidth. Multilink Frame Relay (MFR) is supported on User-to-Network Interfaces (UNI) and Network-to-Network Interfaces (NNI) in Frame Relay networks.
History for the Multilink Frame Relay (FRF.16.1) Feature
Finding Support Information for Platforms and Cisco IOS and Catalyst OS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Contents
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Prerequisites for Multilink Frame Relay (FRF.16.1)
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Prerequisites for Multilink Frame Relay (FRF.16.1)
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Restrictions for Multilink Frame Relay (FRF.16.1)
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Information About Multilink Frame Relay (FRF.16.1)
To enable multilink Frame Relay (FRF.16.1) variable bandwidth class support, you should understand the following concepts:
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Benefits of Multilink Frame Relay (FRF.16.1)
Flexible Pool of Bandwidth
By combining multiple physical interfaces into a bundle, you can design a Frame Relay interface that has more bandwidth than is available from any single physical interface. For example, many new network applications require more bandwidth than is available on a T1 line. One option is to invest in a T3 line; however, T3 lines can be expensive and are not available in some locations. Multilink Frame Relay provides a cost-effective solution to this problem by allowing multiple T1 lines to be aggregated into a single bundle of bandwidth.
Greater Service Resilience When Links Fail
Greater service resilience is provided when multiple physical interfaces are provisioned as a single bundle. When a link fails, the bundle continues to support the Frame Relay service by transmitting across the remaining bundle links.
Link Integrity Protocol Control Messages
For link management, each end of a bundle link follows the MFR Link Integrity Protocol and exchanges link-control messages with its peer (the other end of the bundle link). For a bundle link to be brought up, each end of the link must complete an exchange of ADD_LINK and ADD_LINK_ACK messages. To maintain the link, both ends periodically initiate the exchange of HELLO and HELLO_ACK messages. This exchange of hello messages and acknowledgments serves as a keepalive mechanism for the link. If a router is sending hello messages but not receiving acknowledgments, it will resend the hello message up to a configured maximum number of times. If the router exhausts the maximum number of retries, the bundle link line protocol is considered down (nonoperational).
The bundle link interface's line protocol status is considered up (operational) when the peer device acknowledges that it will use the same link for the bundle. The line protocol remains up when the peer device acknowledges the hello messages from the local router.
The bundle interface's line protocol status is considered up when the Frame Relay data-link layer at the local router and peer device is synchronized using the Local Management Interface (LMI), when LMI is enabled. The bundle line protocol remains up as long as the LMI keepalives are successful.
Variable Bandwidth Class Support
Multilink Frame Relay (FRF.16.1) variable bandwidth class support allows you to specify the criterion used to activate or deactivate a Frame Relay bundle. Consistent with the Frame Relay Forum Multilink Frame Relay UNI/NNI Implementation Agreement (FRF.16.1), bandwidth classes A (single link), B (all links), and C (threshold) are supported.
Class A (Single Link)
The Frame Relay bundle is provisioned when one or more bundle links indicate by issuing a BL_ACTIVATE message that operational bandwidth is available. When this occurs, the bundle emulates a physical link by issuing a PH_ACTIVATE message to the data-link layer.
When the operational bandwidth of a bundle link fails to meet operational requirements (for instance, if it is in rollback mode), the bundle link issues a BL_DEACTIVATE message. When all bundle links are down in a class A bundle, a PH_DEACTIVATE message is sent to the data-link layer, indicating that the Frame Relay bundle cannot accept frames.
Class B (All Links)
The Frame Relay bundle is provisioned when all bundle links indicate by issuing a BL_ACTIVATE message that operational bandwidth is available. When this occurs, the bundle emulates a physical link by issuing a PH_ACTIVATE message to the data-link layer.
When the operational bandwidth of a bundle link fails to meet operational requirements (for instance, if it is in loopback mode), the bundle link issues a BL_DEACTIVATE message. When any bundle link is down in a class B bundle, a PH_DEACTIVATE message is sent to the data-link layer, indicating that the Frame Relay bundle cannot accept frames.
Class C (Threshold)
The Frame Relay bundle is provisioned when the minimum number of links in the configured bundle issue a BL_ACTIVATE message. When this occurs, the bundle emulates a physical link by issuing a PH_ACTIVATE message to the data-link layer.
When the number of bundle links that are issuing a BL_ACTIVATE message falls below the configured threshold value, a PH_DEACTIVATE message is sent to the data-link layer, indicating that the Frame Relay bundle cannot accept frames.
Load Balancing with Multilink Frame Relay (FRF.16.1)
Multilink Frame Relay provides load balancing across the bundle links within a bundle. If a bundle link chosen for transmission happens to be busy transmitting a long packet, the load-balancing mechanism can try another link, thus solving the problems seen when delay-sensitive packets have to wait.
How to Enable Multilink Frame Relay (FRF.16.1)
This section contains the following procedures:
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Configuring a Multilink Frame Relay Bundle
To configure the bundle interface for multilink Frame Relay, perform the steps in this section.
SUMMARY STEPS
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DETAILED STEPS
Configuring a Multilink Frame Relay Bundle Link
To configure a bundle link interface for multilink Frame Relay, perform the steps in this section.
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DETAILED STEPS
Monitoring and Maintaining Multilink Frame Relay (FRF.16.1)
To monitor and maintain multilink Frame Relay, perform the steps in this section.
SUMMARY STEPS
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DETAILED STEPS
Examples
The following example shows output for the show frame-relay multilink command. Because a particular bundle or bundle link is not specified, information for all bundles and bundle links is displayed:
Router# show frame-relay multilinkBundle: MFR0, state up, class A, no fragmentationID: Bundle-DallasSerial5/1, state up/up, ID: BL-Dallas-1Serial5/3, state up/add-sent, ID: BL-Dallas-3Bundle: MFR1, state down, class B, fragmentationID: Bundle-NewYork#1Serial3/0, state up/up, ID: BL-NewYork-1Serial3/2, state admin-down/idle, ID: BL-NewYork-2The following example shows output for the show frame-relay multilink command when a Frame Relay bundle is configured as bandwidth class C (threshold):
Router# show frame-relay multilinkBundle: MFR0, state down, class C (threshold 3), no fragmentationID: Bundle-DallasSerial5/1, state up/up, ID: BL-Dallas-1Serial5/3, state up/add-sent, ID: BL-Dallas-3The following example shows output for the show frame-relay multilink command when the serial number keyword and argument are specified. It displays information about the specified bundle link:
Router# show frame-relay multilink serial 3/2Bundle links :Serial3/2, HW state :down, Protocol state :Down_idle, LID :Serial3/2Bundle interface = MFR0, BID = MFR0The following examples show output for the show frame-relay multilink command when the serial number keyword and argument and the detailed option are specified. Detailed information about the specified bundle links is displayed. The first example shows a bundle link in the "idle" state. The second example shows a bundle link in the "up" state:
Router# show frame-relay multilink serial 3 detailBundle links:Serial3, HW state = up, link state = Idle, LID = Serial3Bundle interface = MFR0, BID = MFR0Cause code = none, Ack timer = 4, Hello timer = 10,Max retry count = 2, Current count = 0,Peer LID = Serial5/3, RTT = 0 msStatistics:Add_link sent = 0, Add_link rcv'd = 10,Add_link ack sent = 0, Add_link ack rcv'd = 0,Add_link rej sent = 10, Add_link rej rcv'd = 0,Remove_link sent = 0, Remove_link rcv'd = 0,Remove_link_ack sent = 0, Remove_link_ack rcv'd = 0,Hello sent = 0, Hello rcv'd = 0,Hello_ack sent = 0, Hello_ack rcv'd = 0,outgoing pak dropped = 0, incoming pak dropped = 0Router# show frame-relay multilink serial 3 detailBundle links:Serial3, HW state = up, link state = Up, LID = Serial3Bundle interface = MFR0, BID = MFR0Cause code = none, Ack timer = 4, Hello timer = 10,Max retry count = 2, Current count = 0,Peer LID = Serial5/3, RTT = 4 msStatistics:Add_link sent = 1, Add_link rcv'd = 20,Add_link ack sent = 1, Add_link ack rcv'd = 1,Add_link rej sent = 19, Add_link rej rcv'd = 0,Remove_link sent = 0, Remove_link rcv'd = 0,Remove_link_ack sent = 0, Remove_link_ack rcv'd = 0,Hello sent = 0, Hello rcv'd = 1,Hello_ack sent = 1, Hello_ack rcv'd = 0,outgoing pak dropped = 0, incoming pak dropped = 0Configuration Examples for Multilink Frame Relay (FRF.16.1)
This section provides the following configuration examples:
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Configuring Multilink Frame Relay: Example
The following example shows the configuration of bundle "MFR1." Serial interfaces 5/0 and 6/0 are configured as bundle links:
interface MFR1no ip addressmls qos trust dscpframe-relay intf-type dceframe-relay multilink bid router1!interface MFR1.1 point-to-pointip address 10.0.1.1 255.255.255.0ip pim sparse-modemls qos trust dscpframe-relay interface-dlci 100interface Serial5/0encapsulation frame-relay MFR1frame-relay multilink lid first-linkframe-relay multilink hello 9frame-relay multilink retry 3interface Serial6/0encapsulation frame-relay MFR1frame-relay multilink ack 4Configuring Variable Bandwidth Class Support: Example
The following example configures the Frame Relay bundle "MFR1" to use the class B (all links) criterion to be activated or deactivated:
interface MFR1ip address 10.1.1.1 255.255.255.0frame-relay interface-dlci 100frame-relay multilink bandwidth-class bAdditional References
The following sections provide references related to multilink Frame Relay (FRF.16.1).
Related Documents
Frame Relay configuration
Cisco IOS Wide-Area Networking Configuration Guide, Release 12.4T
Frame Relay commands
Cisco IOS Wide-Area Networking Command Reference, Release 12.4T
Standards
MIBs
None
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
RFCs
Technical Assistance
Command Reference
This section documents only commands that are new or modified.
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debug frame-relay multilink
To display debug messages for multilink Frame Relay bundles and bundle links, use the debug frame-relay multilink command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug frame-relay multilink [control [mfr number | serial number]]
no debug frame-relay multilink
Syntax Description
Command Modes
Privileged EXEC (#)
Command History
Usage Guidelines
Caution
Using the debug frame-relay multilink command without the mfr or serial keywords displays error conditions that occur at the bundle layer.
Examples
The following example shows output from the debug frame-relay multilink command for bundle "MFR0," which has three bundle links:
Router# debug frame-relay multilink control MFR000:42:54:Serial5/3(o):msg=Add_link, Link=Serial5/3, Bundle=MFR0, Link id=Serial5/3, BL state=IdleE1 00 01 01 07 4D 46 52 30 0000:42:54:Serial5/2(o):msg=Add_link, Link=Serial5/2, Bundle=MFR0, Link id=Serial5/2, BL state=IdleE1 00 01 01 07 4D 46 52 30 0000:42:54:Serial5/1(o):msg=Add_link, Link=Serial5/1, Bundle=MFR0, Link id=Serial5/1, BL state=IdleE1 00 01 01 07 4D 46 52 30 0000:42:54:%LINK-3-UPDOWN:Interface MFR0, changed state to down00:42:54:Serial5/3(i):msg=Add_link_ack, Link=Serial5/3, Bundle=MFR0, Link id=Serial5/3, BL state=Add_sentE1 00 02 01 07 4D 46 52 30 0000:42:54:Serial5/2(i):msg=Add_link_ack, Link=Serial5/2, Bundle=MFR0, Link id=Serial5/2, BL state=Add_sentE1 00 02 01 07 4D 46 52 30 0000:42:54:Serial5/1(i):msg=Add_link_ack, Link=Serial5/1, Bundle=MFR0, Link id=Serial5/1, BL state=Add_sentE1 00 02 01 07 4D 46 52 30 0000:42:54:%SYS-5-CONFIG_I:Configured from console by console00:43:00:Serial5/1(i):msg=Add_link, Link=Serial5/1, Bundle=MFR0, Link id=Serial5/1, BL state=Ack_rxE1 00 01 01 07 4D 46 52 30 0000:43:00:Serial5/1(o):msg=Add_link_ack, Link=Serial5/1, Bundle=MFR0, Link id=Serial5/1, BL state=Ack_rxE1 00 02 01 07 4D 46 52 30 0000:43:00:%LINK-3-UPDOWN:Interface MFR0, changed state to up00:43:00:Serial5/1(i):msg=Hello, Link=Serial5/1, Bundle=MFR0, Linkid=Serial5/1, BL state=UpE1 00 04 03 06 30 A7 E0 54 0000:43:00:Serial5/1(o):msg=Hello_ack, Link=Serial5/1, Bundle=MFR0, Link id=Serial5/1, BL state=UpE1 00 05 03 06 90 E7 0F C2 0600:43:01:Serial5/2(i):msg=Add_link, Link=Serial5/2, Bundle=MFR0, Link id=Serial5/2, BL state=Ack_rxE1 00 01 01 07 4D 46 52 30 0000:43:01:Serial5/2(o):msg=Add_link_ack, Link=Serial5/2, Bundle=MFR0, Link id=Serial5/2, BL state=Ack_rxE1 00 02 01 07 4D 46 52 30 0000:43:01:Serial5/2(i):msg=Hello, Link=Serial5/2, Bundle=MFR0, Linkid=Serial5/2, BL state=UpE1 00 04 03 06 30 A7 E0 54 0000:43:01:Serial5/2(o):msg=Hello_ack, Link=Serial5/2, Bundle=MFR0, Link id=Serial5/2, BL state=UpE1 00 05 03 06 90 E7 0F C2 0600:43:01:%LINEPROTO-5-UPDOWN:Line protocol on Interface Serial5/1, changed state to up00:43:01:Serial5/3(i):msg=Add_link, Link=Serial5/3, Bundle=MFR0, Link id=Serial5/3, BL state=Ack_rxE1 00 01 01 07 4D 46 52 30 0000:43:01:Serial5/3(o):msg=Add_link_ack, Link=Serial5/3, Bundle=MFR0, Link id=Serial5/3, BL state=Ack_rxE1 00 02 01 07 4D 46 52 30 0000:43:01:Serial5/3(i):msg=Hello, Link=Serial5/3, Bundle=MFR0, Linkid=Serial5/3, BL state=UpE1 00 04 03 06 30 A7 E0 54 0000:43:01:Serial5/3(o):msg=Hello_ack, Link=Serial5/3, Bundle=MFR0, Link id=Serial5/3, BL state=UpE1 00 05 03 06 90 E7 0F C2 0600:43:02:%LINEPROTO-5-UPDOWN:Line protocol on Interface Serial5/2 , changed state to up00:43:02:%LINEPROTO-5-UPDOWN:Line protocol on Interface Serial5/3 , changed state to upTable 1 describes the significant fields shown in the display.
Related Commands
show frame-relay multilink
Displays configuration information and statistics about multilink Frame Relay bundles and bundle links.
encapsulation frame-relay mfr
To create a multilink Frame Relay bundle link and to associate the link with a bundle, use the encapsulation frame-relay mfr command in interface configuration mode. To remove the bundle link from the bundle, use the no form of this command.
encapsulation frame-relay mfr number [name]
no encapsulation frame-relay mfr number [name]
Syntax Description
Command Default
Frame Relay encapsulation is not enabled.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
Use the name argument to assign a LID name to a bundle link. This name will be used to identify the bundle link to peer devices and to enable the devices to determine which bundle links are associated with which bundles. The LID name can also be assigned or changed by using the frame-relay multilink lid command on the bundle link interface. If the LID name is not assigned, the default name is the name of the physical interface.
Tips
To remove a bundle link from a bundle, use the no encapsulation frame-relay mfr command or configure a new type of encapsulation on the interface by using the encapsulation command.
Examples
The following example shows serial interface 0 being associated as a bundle link with bundle interface "mfr0." The bundle link identification name is "BL1."
interface mfr0!interface serial 0encapsulation frame-relay mfr0 BL1Related Commands
frame-relay multilink ack
To configure the number of seconds for which a bundle link will wait for a hello message acknowledgment before resending the hello message, use the frame-relay multilink ack command in interface configuration mode. To reset this parameter to the default setting, use the no form of this command.
frame-relay multilink ack seconds
no frame-relay multilink ack
Syntax Description
seconds
Number of seconds for which a bundle link will wait for a hello message acknowledgment before resending the hello message. Range: 1 to 10. Default: 4.
Command Default
The acknowledgment interval is 4 seconds.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
The frame-relay multilink ack command can be configured only on bundle link interfaces that have been associated with a bundle using the encapsulation frame-relay mfr command.
Both ends of a bundle link send out hello messages at regular intervals. When a peer device receives a hello message, it responds by sending an acknowledgment. This exchange of hello messages and acknowledgments serves as a keepalive mechanism for the link. If the bundle link sends a hello message but does not receive an acknowledgment, it will resend the hello message up to a configured maximum number of times. If the bundle link exhausts the maximum number of retries, the bundle link line protocol is considered down (nonoperational).
The frame-relay multilink ack command setting on the local router is independent of the setting on the peer device.
Examples
The following example shows how to configure the bundle link to wait 6 seconds before resending hello messages:
interface serial0encapsulation frame-relay mfr0frame-relay multilink ack 6Related Commands
frame-relay multilink bandwidth-class
To specify the criterion used to activate or deactivate a Frame Relay bundle, use the frame-relay multilink bandwidth-class command in interface configuration mode. To reset the bandwidth class to the default, use the no form of this command.
frame-relay multilink bandwidth-class [a | b | c [threshold]]
no frame-relay multilink bandwidth-class
Syntax Description
Command Default
Frame Relay bundles use bandwidth class A (single link).
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
The frame-relay multilink bandwidth-class command can be configured only on a bundle's main interface. If no bandwidth class is specified by using the frame-relay multilink bandwidth-class command, the Frame Relay bundle uses the class A (single link) criterion.
Examples
The following example shows how to specify the class B (all links) bandwidth class to trigger activation or deactivation of the Frame Relay bundle on MFR interface 0:
interface mfr0frame-relay multilink bandwidth-class bThe following example shows how to specify the class C (threshold) bandwidth class to trigger activation or deactivation of the Frame Relay bundle on MFR interface 0, where the minimum threshold of links indicating BL_ACTIVATE is 3:
interface mfr0frame-relay multilink bandwidth-class c 3Related Commands
frame-relay multilink bid
To assign a bundle identification (BID) name to a multilink Frame Relay bundle, use the frame-relay multilink bid command in interface configuration mode. To reset the name to the default, use the no form of this command.
frame-relay multilink bid name
no frame-relay multilink bid
Syntax Description
Command Default
The BID name is assigned automatically as "mfr" followed by the number assigned to the bundle.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
This command can be entered only on the multilink Frame Relay bundle interface.
Note
Only one BID is allowed per bundle. A later entry of the frame-relay multilink bid command supersedes prior entries.
The local and peer BIDs do not have to be unique.
Examples
The following example shows how to assign a BID of "bundle1" to the multilink Frame Relay bundle. The previous BID for the bundle was "mfr0."
interface mfr0frame-relay multilink bid bundle1Related Commands
frame-relay multilink hello
To configure the interval at which a bundle link will send out hello messages, use the frame-relay multilink hello command in interface configuration mode. To reset this value to the default setting, use the no form of this command.
frame-relay multilink hello seconds
no frame-relay multilink hello
Syntax Description
seconds
Interval, in seconds, at which a bundle link will send out hello messages. Range: 1 to 180. Default: 10.
Command Default
The interval is set at 10 seconds.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
The frame-relay multilink hello command can be configured only on bundle link interfaces that have been associated with a bundle using the encapsulation frame-relay mfr command.
Both ends of a bundle link send out hello messages at regular intervals. When a peer device receives a hello message, it responds by sending an acknowledgment. This exchange of hello messages and acknowledgments serves as a keepalive mechanism for the link. If the bundle link sends a hello message but does not receive an acknowledgment, it will resend the hello message up to a configured maximum number of times. If the bundle link exhausts the maximum number of retries, the bundle link line protocol is considered down (nonoperational).
The setting of the hello message interval on the local router is independent of the setting on the peer device.
Examples
The following example shows how to configure a bundle link to send hello messages every 15 seconds:
interface serial0encapsulation frame-relay mfr0frame-relay multilink hello 15Related Commands
frame-relay multilink lid
To assign a bundle link identification (LID) name to a multilink Frame Relay bundle link, use the frame-relay multilink lid command in interface configuration mode. To reset the name to the default, use the no form of this command.
frame-relay multilink lid name
no frame-relay multilink lid
Syntax Description
name
Bundle link identification (LID) name. The name can be up to 49 characters long. The default is the name of the physical interface.
Command Default
The name of the physical interface is used as the LID.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
The frame-relay multilink lid command can be configured only on bundle link interfaces that have been associated with a bundle using the encapsulation frame-relay mfr command.
Note
The LID will be used to identify the bundle link to peer devices and to enable the devices to identify which bundle links are associated with which bundles. The LID can also be assigned when the bundle link is created by using the encapsulation frame-relay mfr command with the name argument. If the LID is not assigned, the default LID is the name of the physical interface.
The local and peer LIDs do not have to be unique.
Examples
The following example shows the LID "BL1" assigned to serial interface 0:
interface serial 0encapsulation frame-relay mfr0frame-relay multilink lid BL1Related Commands
frame-relay multilink output-threshold
To configure the number of bytes that a bundle link will transmit before the load-balancing mechanism causes transmission to roll over to the next available link, use the frame-relay multilink output-threshold command in interface configuration mode. To reset this value to the default setting, use the no form of this command.
frame-relay multilink output-threshold bytes
no frame-relay multilink output-threshold
Syntax Description
bytes
Number of bytes that a bundle link will transmit before the load-balancing mechanism causes transmission to roll over to the next link. Range: 20 to 2147483647. Default: 300.
Command Default
The number of bytes transmitted is set at 300.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
Multilink Frame Relay enables load balancing across bundle links that are in the same bundle. When a bundle link has reached its output threshold, transmission rolls over to the next available bundle link in the bundle.
The output threshold mechanism applies only when the bundle interface is using FIFO output queueing. When the bundle interface is not using FIFO output queuing, the algorithm for choosing a bundle link interface for output selects the bundle link that has the empty or shortest output queue.
The default output threshold is 300 bytes. This default value will work effectively if all the bundle links in the bundle have the same speed. To efficiently use bundle links with different speeds, use the frame-relay multilink output-threshold command to adjust the output threshold of the links as appropriate.
The frame-relay multilink output-threshold command can be used on the bundle interface and the bundle links. If the command is used on the bundle interface, the configured output threshold will apply to all bundle links in the bundle. If the command is used on a specific bundle link, the output threshold will overwrite the current setting for that bundle link.
Examples
The following example shows how to configure the bundle link output threshold at 600 bytes. When the bundle link reaches the threshold, transmission will roll over to the next link.
interface serial0encapsulation frame-relay mfr0frame-relay multilink output-threshold 600Related Commands
frame-relay multilink retry
To configure the maximum number of times that a bundle link will resend a hello message while waiting for an acknowledgment, use the frame-relay multilink retry command in interface configuration mode. To reset this value to the default setting, use the no form of this command.
frame-relay multilink retry number
no frame-relay multilink retry
Syntax Description
number
Maximum number of times that a bundle link will resend a hello message while waiting for an acknowledgment. Range: 1 through 5. Default: 2.
Command Default
The number of retries is set at 2.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
The frame-relay multilink retry command can be configured only on bundle link interfaces that have been associated with a bundle using the encapsulation frame-relay mfr command.
If the bundle link sends the maximum number of hello messages without receiving an acknowledgment, the bundle link line protocol is considered down (nonoperational).
The maximum number of retries configured on the local router is independent of the maximum number configured on the peer device.
Examples
The following example shows how to configure a bundle link to send a hello message a maximum of 3 times while waiting for an acknowledgment:
interface serial0encapsulation frame-relay mfr0frame-relay multilink retry 3Related Commands
interface mfr
To configure a multilink Frame Relay bundle interface, use the interface mfr command in global configuration mode. To remove the bundle interface, use the no form of this command.
interface mfr number
no interface mfr number
Syntax Description
Command Default
A Frame Relay bundle interface is not configured.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
Frame Relay encapsulation is the default encapsulation type for multilink Frame Relay bundle interfaces.
A bundle interface is a virtual interface that serves as the Frame Relay data link and performs the same functions as a physical interface. The bundle is made up of physical serial links, called bundle links. The bundle links within a bundle function as one physical link and one pool of bandwidth. Functionality that you want to apply to the bundle links must be configured on the bundle interface.
The no interface mfr command will work only if all bundle links have been removed from the bundle by using the no encapsulation frame-relay mfr command.
Examples
The following example shows the configuration of a bundle interface called "mfr0." The bundle identification (BID) name "BUNDLE-A" is assigned to the bundle. Serial interfaces 0 and 1 are assigned to the bundle as bundle links.
interface mfr0frame-relay multilink bid BUNDLE-A!interface serial0encapsulation frame-relay mfr0!interface serial1encapsulation frame-relay mfr0Related Commands
show frame-relay multilink
To display configuration information and statistics about multilink Frame Relay bundles and bundle links, use the show frame-relay multilink command in privileged EXEC mode.
show frame-relay multilink [mfr number | serial number] [detailed]
Syntax Description
Command Default
Information for all bundles and bundle links is displayed.
Command Modes
Privileged EXEC (#)
Command History
Usage Guidelines
If you do not specify a bundle or bundle link, information for all bundles and bundle links is displayed.
Examples
All Bundles and Bundle Links: Example
The following example shows output for the show frame-relay multilink command (see Table 2 for descriptions of the fields). Because a specific bundle or bundle link is not specified, information for all bundles and bundle links is displayed:
Router# show frame-relay multilinkBundle:MFR0, State = up, class = A, fragmentation disabledBID = MFR0Bundle links :Serial2/1:3, HW state :up, Protocol state :Idle, LID :Serial2/1:3Serial2/1:2, HW state :up, Protocol state :Idle, LID :Serial2/1:2Serial2/1:1, HW state :up, Protocol state :Idle, LID :Serial2/1:1The following example shows output for the show frame-relay multilink command when a Frame Relay bundle is configured as bandwidth class C (threshold) (see Table 2 for descriptions of the fields):
Router# show frame-relay multilinkBundle: MFR0, state down, class C (threshold 2), no fragmentationID: Bundle-DallasSerial5/1, state up/up, ID: BL-Dallas-1Serial5/3, state up/add-sent, ID: BL-Dallas-3Bundle Link: Example
The following example shows output for the show frame-relay multilink command when it is issued with the serial number option (see Table 2 for descriptions of the fields). It displays information about the specified bundle link:
Router# show frame-relay multilink serial 3/2Bundle links :Serial3/2, HW state : down, Protocol state :Down_idle, LID :Serial3/2Bundle interface = MFR0, BID = MFR0Detailed Bundle Links: Examples
The following example shows output for the show frame-relay multilink command when it is issued with the serial number and detailed options (see Table 2 for descriptions of the fields). The example shows a bundle link in the "idle" state:
Router# show frame-relay multilink serial 3 detailedBundle links:Serial3, HW state = up, link state = Idle, LID = Serial3Bundle interface = MFR0, BID = MFR0Cause code = none, Ack timer = 4, Hello timer = 10,Max retry count = 2, Current count = 0,Peer LID = Serial5/3, RTT = 0 msStatistics:Add_link sent = 0, Add_link rcv'd = 10,Add_link ack sent = 0, Add_link ack rcv'd = 0,Add_link rej sent = 10, Add_link rej rcv'd = 0,Remove_link sent = 0, Remove_link rcv'd = 0,Remove_link_ack sent = 0, Remove_link_ack rcv'd = 0,Hello sent = 0, Hello rcv'd = 0,Hello_ack sent = 0, Hello_ack rcv'd = 0,outgoing pak dropped = 0, incoming pak dropped = 0The following example shows output for the show frame-relay multilink command when it is issued with the serial number and detailed options (see Table 2 for descriptions of the fields). The example shows a bundle link in the "up" state:
Router# show frame-relay multilink serial 3 detailedBundle links:Serial3, HW state = up, link state = Up, LID = Serial3Bundle interface = MFR0, BID = MFR0Cause code = none, Ack timer = 4, Hello timer = 10,Max retry count = 2, Current count = 0,Peer LID = Serial5/3, RTT = 4 msStatistics:Add_link sent = 1, Add_link rcv'd = 20,Add_link ack sent = 1, Add_link ack rcv'd = 1,Add_link rej sent = 19, Add_link rej rcv'd = 0,Remove_link sent = 0, Remove_link rcv'd = 0,Remove_link_ack sent = 0, Remove_link_ack rcv'd = 0,Hello sent = 0, Hello rcv'd = 1,Hello_ack sent = 1, Hello_ack rcv'd = 0,outgoing pak dropped = 0, incoming pak dropped = 0Table 2 describes significant fields shown in the displays.
Related Commands
debug frame-relay multilink
Displays debug messages for multilink Frame Relay bundles and bundle links.
Glossary
BID—Bundle identification. The BID is the name used to identify the bundle. The BID can be assigned, or the default can be used.
BL_ACTIVATE—A message that controls the addition of a bundle link to a Frame Relay bundle.
BL_DEACTIVATE—A message that controls the removal a bundle link from a Frame Relay bundle.
bundle—A logical grouping of one or more physical interfaces using the formats and procedures of multilink Frame Relay. A bundle emulates a physical interface to the Frame Relay data-link layer. The bundle is also referred to as the MFR interface.
bundle link—An individual physical interface that is a member of a bundle.
DLCI—data-link connection identifier. A value that identifies a permanent virtual circuit (PVC) in a Frame Relay network.
HELLO message—A message that notifies a peer endpoint that the local endpoint is in the operational state (up).
HELLO_ACK—A message that notifies a peer endpoint that a hello message has been received.
LID—link identification. The LID is the name used to identify a bundle link. The LID can be assigned, or the default can be used.
LMI—Local Management Interface. A set of enhancements to the basic Frame Relay specification. LMI includes support for a keepalive mechanism, which verifies that data is flowing; a multicast mechanism, which provides the network server with its local DLCI and the multicast DLCI; global addressing, which gives DLCIs global rather than local significance in Frame Relay networks; and a status mechanism, which provides an ongoing status report on the DLCIs known to the switch.
NNI—Network-to-Network Interface. The interface between two Frame Relay devices that are both located in a private network or both located in a public network.
PH_ACTIVATE—A message that indicates that the Frame Relay bundle is up.
PH_DEACTIVATE—A message that indicates that the Frame Relay bundle is down.
UNI—User-to-Network Interface. The interface between a Frame Relay device in a public network and a Frame Relay device in a private network.
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