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hold-time

Syntax

Hierarchy Level

Hierarchy Level (ae- interfaces) (PTX5000, PTX1000, PTX10002, PTX10008, PTX10016, and MX Series routers)

Description

Specify the hold-time value to use to damp shorter interface transitions milliseconds. The hold timer enables interface damping by not advertising interface transitions until the hold timer duration has passed. When a hold-down timer is configured and the interface goes from up to down, the down hold-time timer is triggered. Every interface transition that occurs during the hold-time is ignored. When the timer expires and the interface state is still down, then the router begins to advertise the interface as being down. Similarly, when a hold-up timer is configured and an interface goes from down to up, the up hold-time timer is triggered. Every interface transition that occurs during the hold-time is ignored. When the timer expires and the interface state is still up, then the router begins to advertise the interface as being up.

The attribute “up” and “down” is mandatory when we configure the knob “hold-time”. Failing to configure either one, will result in a commit error.

We recommend you to configure sub-second down hold timer value as 500 milliseconds on:

  • MX204 router

  • MX routers with MPC7E, MPC8E, MPC9E, MPC10E, and MX10003-LC2103 MPCs

The sub-second down hold timer is not supported on the interfaces created on MX routers with MPC3E, MPC4E, MPC5E, MPC5EQ, MPC6E, and MPC11E MPCs. The sub-second hold timer is a configuration of hold timer less than a second.

Starting from Junos OS release 21.4R1, you can specify the hold-time value on aggregated ethernet interfaces. When you configure hold-timer for ae- interfaces, we recommend not to configure the hold-time for member links.

Note:
  • We recommend that you configure the hold-time value after determining an appropriate value by performing repeated tests in the actual hardware environment. This is because the appropriate value for hold-time depends on the hardware (XFP, SFP, SR, ER, or LR) used in the networking environment.

  • The hold-time option is not available for controller interfaces.

Note:

On MX Series routers with MPC3E and MPC4E, we recommend that you do not configure the hold-down timer to be less than 1 second. On MX Series routers with MPC5EQ-100G10G (MPC5EQ) or MPC6E (MX2K-MPC6E) with 100-Gigabit Ethernet MIC with CFP2 OTN interfaces, we recommend that you do not configure the hold-down timer to be less than 3 seconds.

Default

Interface transitions are not damped.

Options

down milliseconds—Hold time to use when an interface transitions from up to down. Junos OS advertises the transition within 100 milliseconds of the time value you specify.

  • Range: 0 through 4,294,967,295

  • Default: 0 (interface transitions are not damped)

up milliseconds—Hold time to use when an interface transitions from down to up. Junos OS advertises the transition within 100 milliseconds of the time value you specify.

  • Range: 0 through 4,294,967,295

  • Default: 0 (interface transitions are not damped)

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.

Release Information

Statement introduced before Junos OS Release 7.4.

Statement introduced in Junos OS Release 12.2 for ACX Series Universal Metro Routers.