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Physical Interface Properties

The physical interfaces undergo various transitions which is advertised to the Junos OS for proper functioning of the routers and switches. Accounting profiles that specify the characteristics of data about the traffic passing through the routers and switches can also be configured on the physical interfaces. Simple Network Management Protocol (SNMP) notifications can be enabled on the physical interface to provide information about the state of an interface or when a connection changes. The interface offers to configure various modes like short-reach-mode, flow-control and media type on the devices for ease of access.

Damping Shorter Physical Interface Transitions

By default, when an interface changes from being up to being down, or from down to up, this transition is advertised immediately to the hardware and Junos OS. In some situations—for example, when an interface is connected to an add/drop multiplexer (ADM) or wavelength-division multiplexer (WDM), or to protect against SONET/SDH framer holes—you might want to damp interface transitions. This means not advertising the interface’s transition until a certain period of time has passed, called the hold-time. When you have damped interface transitions 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 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. For information about physical interface damping, see Physical Interface Damping Overview.

This task applies to damping shorter physical interface transitions in milliseconds. To damp longer physical interface transitions in seconds, see Damping Longer Physical Interface Transitions.

To configure damping of shorter physical interface transitions:

  1. Select the interface to damp, where the interface name is interface-type-fpc/pic/port:
  2. Configure the hold-time for link up and link down.

The hold time can be a value from 0 through 4,294,967,295 milliseconds. The default value is 0, which means that interface transitions are not damped. Junos OS advertises the transition within 100 milliseconds of the time value you specify.

For most Ethernet interfaces, hold timers are implemented using a one-second polling algorithm. For 1-port, 2-port, and 4-port Gigabit Ethernet interfaces with small form-factor pluggable transceivers (SFPs), hold timers are interrupt-driven.

Note:

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

Configuring Accounting for the Physical Interface

Accounting Profiles Overview

Juniper Networks routers and switches can collect various kinds of data about traffic passing through the router and switch. You can set up one or more accounting profiles that specify some common characteristics of this data, including the following:

  • The fields used in the accounting records

  • The number of files that the router or switch retains before discarding, and the number of bytes per file

  • The polling period that the system uses to record the data

You configure the profiles and define a unique name for each profile using statements at the [edit accounting-options] hierarchy level. There are two types of accounting profiles: interface profiles and filter profiles. You configure interface profiles by including the interface-profile statement at the [edit accounting-options] hierarchy level. You configure filter profiles by including the filter-profile statement at the [edit accounting-options] hierarchy level. For more information, see the Junos OS Network Management Administration Guide for Routing Devices.

You apply filter profiles by including the accounting-profile statement at the [edit firewall filter filter-name] and [edit firewall family family filter filter-name] hierarchy levels. For more information, see the Routing Policies, Firewall Filters, and Traffic Policers User Guide.

Configuring Accounting for the Physical Interface

Before you begin

You must configure a profile to collect error and statistic information for input and output packets on a particular physical interface. An accounting profile specifies what statistics should be collected and written to a log file. For more information on how to configure an accounting-data log file, see the Configuring Accounting-Data Log Files.

An interface profile specifies the information collected and written to a log file. You can configure a profile to collect error and statistic information for input and output packets on a particular physical interface.

  1. To configure which statistics should be collected for an interface, include the fields statement at the [edit accounting-options interface-profile profile-name] hierarchy level.
  2. Each accounting profile logs its statistics to a file in the /var/log directory. To configure which file to use, include the file statement at the [edit accounting-options interface-profile profile-name] hierarchy level.
    Note:

    You must specify a file statement for the interface profile that has already been configured at the [edit accounting-options] hierarchy level. For more information, see the Configuring Accounting-Data Log Files

  3. Each interface with an accounting profile enabled has statistics collected once per interval time specified for the accounting profile. Statistics collection time is scheduled evenly over the configured interval. To configure the interval, include the interval statement at the [edit accounting-options interface-profile profile-name] hierarchy level.
    Note:

    The minimum interval allowed is 1 minute. Configuring a low interval in an accounting profile for a large number of interfaces might cause serious performance degradation.

  4. To configure the interfaces on which the accounting needs to be performed, apply the interface profile to a physical interface by including the accounting-profile statement at the [edit interfaces interface-name] hierarchy level.

Displaying Accounting Profile for the Physical Interface

Purpose

To display the configured accounting profile a particular physical interface at the [edit accounting-options interface-profile profile-name] hierarchy level:

  • interface-name—ge-1/0/1

  • Interface profile —if_profile

  • File name—if_stats

  • Interval—15 minutes

Action

  • Run the show command at the [edit edit interfaces ge-1/0/1] hierarchy level.

  • Run the show command at the [edit accounting-options] hierarchy level.

Meaning

The configured accounting and its associated set options are displayed as expected.

Enabling or Disabling SNMP Notifications on Physical Interfaces

By default, Simple Network Management Protocol (SNMP) notifications are sent when the state of an interface or a connection changes. You can enable or disable these notification based on you requirements.

To explicitly enable sending SNMP notifications on the physical interface, perform the following steps:

  1. In configuration mode, go to the [edit interfaces interface-name] hierarchy level:
  2. Configure the traps option to enable sending of Simple Network Management Protocol (SNMP) notifications when the state of the connection changes.

To disable sending SNMP notifications on the physical interface, perform the following steps:

  1. In configuration mode, go to the [edit interfaces interface-name] hierarchy level:

  2. Configure the no-traps option to disable sending of Simple Network Management Protocol (SNMP) notifications when the state of the connection changes.

Configuring Ethernet Loopback Capability

To place an interface in loopback mode, include the loopback statement:

To return to the default—that is, to disable loopback mode—delete the loopback statement from the configuration:

To explicitly disable loopback mode, include the no-loopback statement:

You can include the loopback and no-loopback statements at the following hierarchy levels:

  • [edit interfaces interface-name aggregated-ether-options]

  • [edit interfaces interface-name ether-options]

Configuring Short Reach Mode on QFX5100-48T

You can enable short-reach mode for individual as well as a range of copper-based 10-Gigabit Ethernet interfaces using short cable lengths (less than 10m) on the QFX5100-48T switch. Short-reach mode reduces power consumption up to 5W on these interfaces.

  1. To enable short-reach mode on an individual interface, issue the following command:

    For example, to enable short-reach mode on port 0 on PIC 0, issue the following command:

  2. To enable short-reach mode on a range of interfaces, issue the following command:

    For example, to enable short-reach mode on a range of interfaces between port 0 and port 47 on PIC 0, issue the following command:

  3. To disable short-reach mode on an individual interface, issue the following command:

    For example, to disable short-reach mode on port 0 on PIC 0, issue the following command:

  4. To disable short-reach mode on a range of interfaces, issue the following command:

    For example, to disable short-reach mode on a range of interfaces between port 0 and port 47 on PIC 0, issue the following command:

Configuring Flow Control

By default, the router or switch imposes flow control to regulate the amount of traffic sent out on a Fast Ethernet, Tri-Rate Ethernet copper, Gigabit Ethernet, and 10-Gigabit Ethernet interface. Flow control is not supported on the 4-port Fast Ethernet PIC. This is useful if the remote side of the connection is a Fast Ethernet or Gigabit Ethernet switch.

You can disable flow control if you want the router or switch to permit unrestricted traffic. To disable flow control, include the no-flow-control statement:

To explicitly reinstate flow control, include the flow-control statement:

You can include these statements at the following hierarchy levels:

  • [edit interfaces interface-name aggregated-ether-options]

  • [edit interfaces interface-name ether-options]

  • [edit interfaces interface-name fastether-options]

  • [edit interfaces interface-name gigether-options]

Note:

On the Type 5 FPC, to prioritize control packets in case of ingress oversubscription, you must ensure that the neighboring peers support MAC flow control. If the peers do not support MAC flow control, then you must disable flow control.

Disabling a Physical Interface

Disabling a Physical Interface

You can disable a physical interface, marking it as being down, without removing the interface configuration statements from the configuration.

CAUTION:

Dynamic subscribers and logical interfaces use physical interfaces for connection to the network. The Junos OS allows you to set the interface to disable and commit the change while dynamic subscribers and logical interfaces are still active. This action results in the loss of all subscriber connections on the interface. Use care when disabling interfaces.

To disable a physical interface:

  1. In configuration mode, go to [edit interfaces interface-name] hierarchy level.
  2. Include the disable statement.
Note:

On the router, when you use the disable statement at the edit interfaces hierarchy level, depending on the PIC type, the interface might or might not turn off the laser. Older PIC transceivers do not support turning off the laser, but newer Gigabit Ethernet PICs with SFP and XFP transceivers do support it and the laser will be turned off when the interface is disabled.

Laser Warning:

Do not stare into the laser beam or view it directly with optical instruments even if the interface has been disabled.

Example: Disabling a Physical Interface

Sample interface configuration:

Disabling the interface:

Verifying the interface configuration:

Effect of Disabling Interfaces on T series PICs

The following table describes the effect of using the set interfaces disable interface_name statement on T series PICs.

Table 1: Effect of set interfaces disable <interface_name> on T series PICs

PIC Model Number

PIC Description

Type of PIC

Behaviour

PF-12XGE-SFPP

10-Gigabit Ethernet LAN/WAN PIC with SFP+ (T4000 Router)

5

Tx laser disabled

PF-24XGE-SFPP

10-Gigabit Ethernet LAN/WAN PIC with Oversubscription and SFP+ (T4000 Router)

5

Tx laser disabled

PF-1CGE-CFP

100-Gigabit Ethernet PIC with CFP (T4000 Router)

5

Tx laser disabled

PD-4XGE-XFP

10-Gigabit Ethernet, 4-port LAN/WAN XFP

4

Tx laser disabled

PD-5-10XGE-SFPP

10-Gigabit LAN/WAN with SFP+

4

Tx laser disabled

PD-1XLE-CFP

40-Gigabit with CFP

4

Tx laser disabled

PD-1CE-CFP-FPC4

100-Gigabit with CFP

4

Tx laser disabled

PD-TUNNEL

40-Gigabit Tunnel Services

4

NA

PD-4OC192-SON-XFP

OC192/STM64, 4-port XFP

4

Tx laser not disabled

PD-1OC768-SON-SR

OC768c/STM256, 1-port

4

Tx laser not disabled

Release History Table
Release
Description
19.3R1
Starting with Junos OS Release 19.3R1, you can configure the 2-port 40-Gigabit Ethernet QSFP+/100-Gigabit Ethernet QSFP28 uplink module on EX4300-48MP switches to operate either two 40-Gigabit Ethernet ports or two 100-Gigabit Ethernet ports.
19.1R1
Starting with Junos OS Release 19.1R1, in the 2-port 40-Gigabit Ethernet QSFP+/1-port 100-Gigabit Ethernet QSFP28 uplink module of EX4300-48MP switches, you can channelize the 100-Gigabit four independent 25-Gigabit Ethernet ports by using breakout cables.