Verifying an ATM-over-SHDSL Configuration

Purpose

Verify that the interface properties are correct.

Action

From the CLI, enter the show interfaces interface-name extensive command.

Sample Output

Physical interface: at-6/0/0, Enabled, Physical link is Up
  Interface index: 141, SNMP ifIndex: 23, Generation: 48
  Link-level type: ATM-PVC, MTU: 4482, Clocking: Internal, ADSL mode, Speed: ADSL,
  Loopback: None
  Device flags   : Present Running
  Link flags     : None
  CoS queues     : 8 supported
  Hold-times     : Up 0 ms, Down 0 ms
  Current address: 00:05:85:c7:44:3c
  Last flapped   : 2005-05-16 05:54:41 PDT (00:41:42 ago)
  Statistics last cleared: Never
  Traffic statistics:
   Input  bytes  :                 4520                    0 bps
   Output bytes  :                39250                    0 bps
   Input  packets:                   71                    0 pps
   Output packets:                 1309                    0 pps
  Input errors:
    Errors: 0, Drops: 0, Invalid VCs: 0, Framing errors: 0, Policed discards: 0,
    L3 incompletes: 0, L2 channel errors: 1, L2 mismatch timeouts: 0, Resource errors: 0
  Output errors:
    Carrier transitions: 3, Errors: 0, Drops: 0, Aged packets: 0, MTU errors: 0,
    Resource errors: 0
  Queue counters:       Queued packets  Transmitted packets      Dropped packets
    0 best-effort                    4                    4                    0
    1 expedited-fo                   0                    0                    0
    2 assured-forw                   0                    0                    0
    3 network-cont                2340                 2340                    0
  SHDSL  alarms   : None
  SHDSL  defects  : None 
  SHDSL media:            Seconds        Count  State
    LOSD                  239206            2  OK
    LOSW                  239208            1  OK
    ES                         3            1  OK
    SES                        0            0  OK
    UAS                        3            1  OK
    
  SHDSL status:
    Line termination 	:STU-R
	 Annex					:Annex B
	 Line Mode				:2–wire
	 Modem Status			:Data
	 Last fail code		:0
	 Framer mode			:ATM
	 Dying Gasp				:Enabled
	 Chipset version		:1
	 Firmware version		:R3.0
  SHDSL Statistics:                        
   Loop Attenuation (dB)			:0.600
	Transmit power (dB)			 	:8.5
	Receiver gain (dB)				:21.420
	SNR sampling (dB)					:39.3690
	Bit rate	 (kbps)					:2304
	Bit error rate						:0
	CRC errors							:0
	SEGA errors							:1
	LOSW errors							:0
	Received cells						:1155429
	Transmitted cells					:1891375
	HEC errors							:0
	Cell drop							:0				

Meaning

The output shows a summary of interface information. Verify the following information:

• The physical interface is Enabled. If the interface is shown as Disabled, do either of the following:
  • In the CLI configuration editor, delete the disable statement at the [edit interfaces interface-name] level of the configuration hierarchy.
  • In the J-Web configuration editor, clear the Disable check box on the Interfaces>interface-name page.
• The physical link is Up. A link state of Down indicates a problem with the interface module, interface port, or physical connection (link-layer errors).
• The Last Flapped time is an expected value. The Last Flapped time indicates the last time the physical interface became unavailable and then available again. Unexpected flapping indicates likely link-layer errors.
• The traffic statistics reflect expected input and output rates. Verify that the number of inbound and outbound bytes and packets matches expected throughput for the physical interface. To clear the statistics and see only new changes, use the clear interfaces statistics interface-name command.
• No SHDSL alarms and defects appear that can render the interface unable to pass packets. When a defect persists for a certain amount of time, it is promoted to an alarm.
  • LOS—Loss of signal. No signal was detected on the line.
  • LOSW—Loss of sync word. A message ID was sent.
  • Power status—A power failure has occurred.
  • LOSD—Loss of signal was detected at the remote application interface.
  • ES—Errored seconds. One or more cyclic redundancy check (CRC) anomalies were detected.
  • SES—Severely errored seconds. At least 50 CRC anomalies were detected.
  • UAS—Unavailable seconds. An interval has occurred during which one or more LOSW defects were detected.

Examine the SHDSL interface status:

• Line termination—SHDSL transceiver unit–remote (STU–R). (Only customer premises equipment is supported.)
• Annex—Either Annex A or Annex B. Annex A is supported in North America, and Annex B is supported in Europe.
• Line Mode—SHDSL mode configured on the G.SHDSL interface pair, either 2-wire or 4-wire.
• Modem Status—Data. Sending or receiving data.
• Last fail code—Code for the last interface failure.
• Framer mode—Framer mode of the underlying interface: ATM.
• Dying Gasp—Ability of a J Series device that has lost power to send a message informing the attached DSL access multiplexer (DSLAM) that it is about to go offline.
• Chipset version—Version number of the chipset on the interface
• Firmware version—Version number of the firmware on the interface.

Examine the operational statistics for a SHDSL interface.

• Loop Attenuation (dB)—Reduction in signal strength measured in decibels.
• Transmit power (dB)—Amount of SHDSL usage in %.
• Receiver gain (dB)—Maximum extraneous signal allowed without causing the output to deviate from an acceptable level.
• SNR sampling (dB)—Signal-to-noise ratio at a receiver point, in decibels.
• Bit Rate (kbps)—Data transfer speed on the SHDSL interface.
• CRC errors—Number of cyclic redundancy check errors.
• SEGA errors—Number of segment anomaly errors. A regenerator operating on a segment received corrupted data.
• LOSW errors—Number of loss of signal defect errors. Three or more consecutively received frames contained one or more errors in the framing bits.
• Received cells—Number of cells received through the interface.
• Transmitted cells—Number of cells sent through the interface.
• HEC errors—Number of header error checksum errors.
• Cell drop—Number of dropped cells on the interface.

Related Topics

For a complete description of show interfaces extensive output, see the JUNOS Interfaces Command Reference.