Step 4: Monitor Statistics for a T1 Interface

Action

To monitor statistics for a T1 interface, use the following JUNOS CLI operational mode command:

user@host> monitor interface t1-fpc/pic/port

Sample Output

user@host> monitor interface t1-1/0/0

Seconds: 2                   Time: 00:04:49             Delay: 0/0/1

Interface: t1-1/1/0, Enabled, Link is Down

Encapsulation: PPP, Keepalives, Speed: T1

Traffic statistics:                                           Current delta

  Input bytes:                          0 (0 bps)                       [0]

  Output bytes:                         0 (0 bps)                       [0]

  Input packets:                        0 (0 pps)                       [0]

  Output packets:                       0 (0 pps)                       [0]

Error statistics:

  Input errors:                         0                               [0]

  Input drops:                          0                               [0]

  Input framing errors:                 0                               [0]

  Policed discards:                     0                               [0]

  L3 incompletes:                       0                               [0]

  L2 channel errors:                    0                               [0]

  L2 mismatch timeouts:                 0                               [0]

  Carrier transitions:                  0                               [0]

  Output errors:                        0                               [0]

  Output drops:                         0                               [0]

  Aged packets:                         0                               [0]

Active alarms : LOF LOS

Active defects: LOF LOS

T1 statistics:

  BPV                                   0                               [0]

  EXZ                                   0                               [0]

  LCV                                   0                               [0]

  PCV                               40335                             [332]

  CS                                    0                               [0]

Interface warnings:

  o Outstanding DS1 alarm(s)

Next='n', Quit='q' or ESC, Freeze='f', Thaw='t', Clear='c', Interface='i'

What It Means

The sample output shows that the T1 interface is enabled but the link is down. The bps value is in bytes per second and not bits per second. To calculate bits per second, multiply the bps value by 8.

The monitor command checks for and displays common interface failures, indicates whether loopback is detected, and shows any increases in framing errors. Use information from this command to help 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 8 lists additional problem situations and actions to help you further diagnose a problem.

Table 8: Problem Situations and Actions

Problem Situation	Action
Framing errors are increasing.	Check the frame checksum 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 diagnostic purposes. Do not leave it on during normal router operations because real-time monitoring of traffic consumes additional CPU and memory resources.