Multilink Bundle and IMA Group Commands

Note:

Unless otherwise specified, references to multilink bundles refer to both multilink (MLPPP) bundles and IMA groups.

multilink-bundle

Syntax

[no] multilink-bundle

Context

config>port

Description

This command enables the context to configure bundle properties for this bundle port.

Default

n/a

fragment-threshold

Syntax

fragment-threshold fragment-threshold

no fragment-threshold

Context

config>port>multilink-bundle

Description

This command sets the maximum length (in bytes) of a fragment transmitted across the specified MLPPP bundle or sets the length of a Tx frame across the specified IMA group bundle in ATM cells.

The no form of this command resets the fragment threshold back to the default value.

Default

128

Parameters

fragment-threshold

specifies the maximum fragment length in bytes (for MLPPP bundles) or the Tx frame size (for IMA bundles)

Values

128 to 512 bytes (MLPPP)

128 bytes (IMA)

member

Syntax

[no] member port-id

Context

config>port>multilink-bundle

Description

This command binds a channel group to a multilink bundle.

To bind a channel group to a multilink bundle, all the timeslots on the channel group must be allocated.

When you configure a channel group on the network side with ppp-auto encapsulation, the system automatically allocates all timeslots to the channel group. When you configure a channel group on the access side with IPCP encapsulation, the system does not automatically allocate all timeslots to the channel group. In order to use the port or channel group as a member in an multilink bundle, you must manually allocate all the timeslots to the channel group before adding it to the bundle.

The following lists the cards, modules, and platforms that support multilink bundles and the number of channel groups on the network and/or access side that can be bound to an MLPPP bundle:

  • T1/E1 ports on the 7705 SAR-A

    Network: 8 Access: 8

  • T1/E1 ports on the 7705 SAR-M

    Network: 16 Access: 8

  • T1/E1 ports on the 7705 SAR-X

    Network: 8 Access: 8

    The following must have all member links of an MLPPP bundle configured on the same card or module:

    • 16-port T1/E1 ASAP Adapter card

      Network: 16 Access: 8

    • 32-port T1/E1 ASAP Adapter card

      Network: 16 Access: 8

    • T1/E1 ports on the 4-port T1/E1 and RS-232 Combination module (on 7705 SAR-H)

      Network: 2 Access: 2

    The following must have all member links of an MLPPP bundle configured on the same card or module, and on the same port:

    • 2-port OC3/STM1 Channelized Adapter card

      Network: 8 Access: 8

    • 4-port OC3/STM1 / 1-port OC12/STM4 Adapter card

      Network: 8 Access: 8

The following lists the cards, modules, and platforms that support IMA groups and the number of channel groups on the network and/or access side that can be bound to an IMA group:

  • T1/E1 ports on the 7705 SAR-M

    IMA: 16

    The following must have all member links of an IMA bundle configured on the same card or module:

    • 16-port T1/E1 ASAP Adapter card

      IMA: 16

    • 32-port T1/E1 ASAP Adapter card

      IMA: 16

    The following must have all member links of an IMA bundle configured on the same card or module, and on the same port:

    • 2-port OC3/STM1 Channelized Adapter card

      IMA: 8

The no form of this command removes the specified channel group from the multilink bundle.

Default

n/a

Parameters

port-id

the physical port ID

Syntax: slot/mda/port.channel

minimum-links

Syntax

minimum-links minimum-links

no minimum-links

Context

config>port>multilink-bundle

Description

This command sets the minimum number of links that must be active for the bundle to be active.

If the number of active links drops below the configured minimum, then the multilink bundle will transition to an operationally down state.

The no form of this command removes the minimum link limit.

Default

1

Parameters

minimum-links

the minimum link limit, expressed as an integer

Values

Table: Minimum Link Limit Values lists the minimum link limit values.

Table: Minimum Link Limit Values

Port

MLPP Bundles

IMA Bundles

Access

Network

Access

T1/E1 ports on the 7705 SAR-A

1 to 8

1 to 8

T1/E1 ports on the 7705 SAR-M

1 to 8

1 to 16

1 to 16

T1/E1 ports on the 7705 SAR-X

1 to 8

1 to 8

T1/E1 ports on the 4-port T1/E1 and RS-232 Combination module (on 7705 SAR-H)

1 to 2

1 to 2

DS1/E1 channels on the 2-port OC3/STM1 Channelized Adapter card

1 to 8

1 to 8

1 to 8

4-port OC3/STM1 / 1-port OC12/STM4 Adapter card

1 to 8

16-port T1/E1 ASAP Adapter card

1 to 8

1 to 16

1 to 16

32-port T1/E1 ASAP Adapter card

1 to 8

1 to 16

1 to 16

mlppp

Syntax

mlppp

Context

config>port>multilink-bundle

Description

This command enables the context to configure MLPPP bundle attributes.

endpoint-discriminator

Syntax

endpoint-discriminator class {ip-address | global-mac-address | null} [discriminator-id discriminator-id]

no endpoint-discriminator

Context

config>port>multilink-bundle>mlppp

Description

This command configures the endpoint-discriminator class and ID. The port must be shut down to modify the endpoint-discriminator parameters.

If the null option is configured, the 7705 SAR will advertise an endpoint-discriminator class value of NULL in link membership negotiations. If the far-end node rejects the NULL object, the 7705 SAR will remove the object from future requests. The null option should only be used if the far-end node cannot support the ip-address or global-mac-address endpoint-discriminator class options, as these options provide more protection from incorrectly adding a link to an MLPPP bundle.

The no form of this command removes the configured parameters.

Parameters

class

specifies the link control protocol endpoint-discriminator class field

Default

global-mac-address (for physical MLPPP bundle)

ip-address (for physical MLPPP bundle protection group)

null (when the endpoint-discriminator option is not present in a received configure request)

discriminator-id

specifies the endpoint-discriminator identifier value within the specified endpoint-discriminator class

Values

any valid IP address

magic-number

Syntax

[no] magic-number

Context

config>port>multilink-bundle>mlppp

Description

This command allows loopback detection to be enabled and disabled for MLPPP bundles. The command is disabled by default. When the magic number option is disabled, the magic number option will not be requested when a member is trying to bring up the LCP layer on a member link; if the remote peer requests this option, it will be rejected. When transmitting echo-requests, a magic number of 0 is used. When responding to echo-requests, a magic number of 0 is sent.

If the magic-number option is enabled, the option is sent to the remote peer during protocol negotiation. If this option is rejected by the remote peer, the router will bring the link up but will be unable to detect loopbacks since the router will always send a magic number of 0 in the echo messages upon rejection. If this option is accepted by the remote peer, the router will send echo messages with randomly generated (non-zero) magic numbers. If the 7705 SAR receives a config-req with the same magic number that was sent out, the router will calculate a new magic number to use and send out another config-request. If the router persistently sees the randomly generated magic number in the received config-req, the router will declare a loopback.

The no form of the command disables the loopback detection.

Default

no magic-number

multiclass

Syntax

multiclass count

no multiclass

Context

config>port>multilink-bundle>mlppp

Description

This command enables multi-class MLPPP (MC-MLPPP) as defined by RFC 2686, The Multi-Class Extension to Multi-Link PPP. The 7705 SAR supports MC-MLPPP bundles with 2, 3 or 4 classes. To change the number of classes, all member links must be removed and then the bundle must be shut down.

The packets transmitted on the MC-MLPPP bundle are sent with class values from 0 to one less than the configured class size. For example, a 4-class MLPPP bundle has 4 classes and transmits packets with class numbers 0, 1, 2, and 3. A 4-class bundle transmits packets with class numbers 0, 1 and 2 and a 2-class bundle transmits packets with class numbers 0 and 1. A 0-class MLPPP bundle has the highest priority.

Entries are created and deleted by the system depending on the number of classes being used by a given MLPPP bundle. The no form of the command disables multi-class MLPPP.

Default

no multiclass

Parameters

count

specifies the number of classes in an MLPPP bundle

Values

2 to 4

mrru

Syntax

mrru mrru

no mrru

Context

config>port>multilink-bundle

Description

This command specifies the maximum received reconstructed unit (MRRU), which is similar to a maximum transmission unit (MTU) but applies only to MLPPP multilink bundles. The MRRU is the maximum frame size that can be reconstructed from multilink fragments. This command is only valid for MLPPP bundles.

The no form of this command resets the MRRU to the default.

Default

1524

Parameters

mrru

the maximum received reconstructed unit size, expressed as an integer

Values

1500 to 2088 bytes (for MLPPP)

1500 to 2090 bytes (for PPP)

red-differential-delay

Syntax

red-differential-delay red-diff-delay [down]

no red-differential-delay

Context

config>port>multilink-bundle

Description

This command sets the maximum acceptable differential delay for individual circuits within a multilink bundle.

The no form of this command restores the red-differential-delay defaults.

Default

n/a

Parameters

red-diff-delay

the maximum red differential delay value, in milliseconds

Values

0 to 25 ms for MLPPP bundles

2 to 75 ms for IMA bundles on the 16-port T1/E1 ASAP Adapter card or 32-port T1/E1 ASAP Adapter card

2 to 75 ms for IMA bundles on the 2-port OC3/STM1 Channelized Adapter card

down

transition the circuit that exceeded the differential delay to a down state (for example, remove it from the multilink bundle from an operational perspective). To transition the circuit back to the up state, the user should shutdown, then no shutdown the channel group.

short-sequence

Syntax

[no] short-sequence

Context

config>port>multilink-bundle

Description

This command specifies that the MLPPP bundle should use short (12 bit) sequence numbers instead of the default 24-bit sequence number. This command is only valid for MLPPP bundles.

The no form of this command disables the short-sequence feature.

Default

no short-sequence

yellow-differential-delay

Syntax

yellow-differential-delay yellow-diff-delay

no yellow-differential-delay

Context

config>port>multilink-bundle

Description

This command sets the yellow warning threshold for the differential delay for members within a multilink bundle. If circuit’s delay exceeds the yellow-differential delay value, a log message and SNMP trap is sent. This command is only valid for MLPPP bundles.

The no form of this command removes the yellow-differential-delay.

Default

n/a

Parameters

yellow-diff-delay

the maximum yellow differential delay threshold value, in milliseconds

Values

1 to 25

ima

Syntax

ima

Context

config>port>multilink-bundle

Description

This command enables the context to configure parameters for an IMA group. An IMA group is a collection of physical links bundled together and assigned to an ATM port. IMA enables a high-speed channel that is composed of ATM cells to be transported as a number of lower-speed circuits. They are then reassembled as the original high-speed ATM channel.

This command is only valid for IMA bundles.

link-delay

Syntax

link-delay {activate | deactivate} milliseconds

no link-delay {activate | deactivate}

Context

config>port>multilink-bundle>ima

Description

This command specifies the time delay between detection of a link activation/deactivation condition and acting upon it (going in/out of the Rx failure state on a link).

Parameters

activate milliseconds

the time, in milliseconds, used to clear an existing LIF, LODS, or FRI-IMA alarm. The time specified determines how long is needed for member links to stabilize before being activated.

Values

1 to 30000 ms

Default

1000

deactivate milliseconds

the time, in milliseconds, used to raise an LIF, LODS, or FRI-IMA alarm. The time specified determines how long before a member link is declared in error and is deactivated.

Values

1 to 30000 ms

Default

2000

test-pattern-procedure

Syntax

test-pattern-procedure

Context

config>port>multilink-bundle>ima

Description

This command enables the context to configure IMA test pattern procedures. This command and its sub-commands are not saved in the router configuration between reboots.

test-link

Syntax

test-link port-id

no test-link

Context

config>port>multilink-bundle>ima>test-pattern-procedure

Description

This command specifies IMA members on which an IMA test pattern procedure is to be performed.

The no form of this command deletes the link from the test-pattern procedure. The test-pattern procedure must be shut down first.

Default

no test-link

Parameters

port-id

the port ID to be used to verify link connectivity within an IMA group

test-pattern

Syntax

test-pattern pattern

no test-pattern

Context

config>port>multilink-bundle>ima>test-pattern-procedure

Description

This command specifies the transmit test pattern in an IMA group loopback operation. This value can only be changed when the test-pattern-procedure command is shut down.

The no form of this command restores the test pattern to the default.

Default

0

Parameters

pattern

specifies an integer taking the following values:

Values

0 to 255

shutdown

Syntax

[no] shutdown

Context

config>port>multilink-bundle>ima>test-pattern-procedure

Description

This command enables a configured IMA test pattern procedure.

The no form of this command disables the IMA test pattern procedure.

version

Syntax

version IMA-version

no version

Context

config>port>multilink-bundle>ima>

Description

This command configures the IMA version for the multilink bundle group. If there is a version mismatch between this IMA group and the far-end IMA group, the IMA group will go operationally down. To change the IMA version, you must first remove all member links from the group.

Only IMA version 1.1 is supported.

Default

1-1

Parameters

IMA-version

specifies the IMA version for this group

Values

1-1 — IMA version 1.1