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Monitor T3 Interfaces

 

This section includes the following information to assist you when troubleshooting T3 interfaces:

Checklist for Monitoring T3 Interfaces

Purpose

To monitor T3 interfaces and begin the process of isolating T3 interface problems when they occur.

Action

Table 1 provides the links and commands for monitoring T3 interfaces.

Table 1: Checklist for Monitoring T3 Interfaces

Tasks

Command or Action

Monitor T3 Interfaces
  1. Display the Status of T3 Interfaces

show interfaces terse t3*

  1. Display the Status of a Specific T3 Interface

show interfaces t3-fpc/pic/port

  1. Display Extensive Status Information for a Specific T3 Interface

show interfaces t3-fpc/pic/port extensive

  1. Monitor Statistics for a T3 Interface

monitor interface t3-fpc/pic/port

Monitor T3 Interfaces

By monitoring T3 interfaces, you begin the process of isolating T3 interface problems when they occur.

To monitor T3 interfaces, follow these steps:

  1. Display the Status of T3 Interfaces

  2. Display the Status of a Specific T3 Interface

  3. Display Extensive Status Information for a Specific T3 Interface

  4. Monitor Statistics for a T3 Interface



Display the Status of T3 Interfaces

Purpose

To display the status of T3 interfaces, use the following Junos OS command-line interface (CLI) operational mode command:

Action

Sample Output

user@host> show interfaces terse t3*

Meaning

The sample output shows the status of both the physical and logical interfaces. See Table 2 for a description of what the output means.

Table 2: Status of T3 Interfaces

Physical Interface

Logical Interface

Status Description

t3-1/0/0

Admin Down

Link Up

t3-1/0/0.0

Admin Up

Link Down

This interface is administratively disabled and the physical link is healthy (Link Up), but the logical interface is not established. The logical interface is down because the physical link is disabled (Link Down).

t3-1/0/1

Admin Up

Link Down

t3-1/0/1.0

Admin Up

Link Down

This interface is not functioning between the local router and the remote router because both the physical and logical links are down (Link Down). The interface is not administratively disabled because both the physical and logical links are up (Admin Up).

t3-1/0/2

Admin Up

Link Up

t3-1/0/2.0

Admin Up

Link Up

This interface has both the physical and logical links up and running.

t3-1/0/3

Admin Up

Link Down

 

This interface does not have a logical link configured.



Display the Status of a Specific T3 Interface

Purpose

To display the status of a specific T3 interface when you need to investigate its status further, use the following Junos OS CLI operational mode command:

Action

Sample Output

user@host> show interfaces t3-1/0/0

Meaning

The first line of the sample output shows the status of the link. If this line shows that the physical link is up, the physical link is healthy and can pass packets. If this line shows that the physical link is down, the physical link is unhealthy and cannot pass packets.



Display Extensive Status Information for a Specific T3 Interface

Purpose

To display extensive status information about a specific T3 interface, use the following Junos OS CLI operational mode command:

Action

Sample Output

user@router> show interfaces t3-1/0/0 extensive

Meaning

The sample output shows where the errors might be occurring. Look at the active alarms and active defects for the T3 interface and investigate the T3 media accordingly. See Checklist of Common T3 Alarms and Errors for an explanation of T3 alarms.



Monitor Statistics for a T3 Interface

Purpose

To monitor statistics for a T3 interface, use the following Junos OS CLI operational mode command:

Action

Sample Output

user@host> monitor interface t3-1/0/0

Meaning

This command checks for and displays common interface failures, indicates whether loopback is detected, and reports any increases in framing errors. Use the information from this command to narrow down possible causes of an interface problem.

Note

If you are accessing the router from the console connection, make sure you set the CLI terminal type using the set cli terminal command.

Table 3 presents problem situations and actions to help you further understand the problem.

Table 3: Problem Situations and Actions

Problem Situation

Action

Framing errors are increasing.

Check the frame check sequence (FCS), scrambling, and subrate configuration.

Framing errors are increasing, and the configuration is correct.

Check the cabling to the router and have the carrier verify the integrity of the line.

Input errors are increasing.

Check the cabling to the router and have the carrier verify the integrity of the line.

Note

We recommend that you use this command only for troubleshooting purposes. Do not leave it on during normal router operations because real-time monitoring of traffic consumes additional CPU and memory resources.

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