Juniper Show Interface Commands

• Show Interfaces
• Show Interfaces Detail
• Show Interfaces Extensive
• Input Errors
• Output Errors
• Output Field Definitions

show interfaces

Sample Output

 user@host> show interfaces t3-5/2/0 
 Physical interface: t3-5/2/0, Enabled, Physical link is Up
   Interface index: 30, SNMP ifIndex: 41
   Link-level type: Frame-Relay, MTU: 4474, Clocking: Internal
   Speed: T3, Loopback: None, CRC: 16, Mode: C/Bit parity
   Device flags   : Present Running
   Interface flags: Point-To-Point SNMP-Traps
   Link flags     : No-Keepalives, DCE
   Input rate     : 35784 bps (1 pps), Output rate: 35792 bps (1 pps)
   Active alarms  : None
   Active defects : None
   Logical interface t3-5/2/0.0 (Index 11) (SNMP ifIndex 42)
     Flags: Point-To-Point SNMP-Traps, DLCI 10, Encapsulation: FR-NLPID
     Input packets: 54 Output packets: 54
     Protocol inet, MTU: 4470
       Addresses, Flags: Is-Preferred Is-Primary
         Destination: 192.168.2.200, Local: 192.168.2.225
     Protocol iso, MTU: 4470
 
   Logical interface t3-5/2/0.1 (Index 12) (SNMP ifIndex 52)
 ...

show interfaces detail (for T3 Interfaces)

Sample Output

 user@host> show interfaces t3-5/2/0 detail 
 Physical interface: t3-5/2/0, Enabled, Physical link is Up
   Interface index: 30, SNMP ifIndex: 41
   Link-level type: Frame-Relay, MTU: 4474, Clocking: Internal
   Speed: T3, Loopback: None, CRC: 16, Mode: C/Bit parity
   Device flags   : Present Running
   Interface flags: Point-To-Point SNMP-Traps
   Link flags     : No-Keepalives, DCE
   Statistics last cleared: Never
   Traffic statistics:
    Input  bytes  :               232855                    0 bps
    Output bytes  :               232914                    0 bps
    Input  packets:                   59                    0 pps
    Output packets:                   59                    0 pps
   Active alarms  : None
   Active defects : None
   Logical interface t3-5/2/0.0 (Index 11) (SNMP ifIndex 42)
     Flags: Point-To-Point SNMP-Traps, DLCI 10, Encapsulation: FR-NLPID
     Traffic statistics:
      Input  bytes  :               233032
      Output bytes  :               233032
      Input  packets:                   59
      Output packets:                   59
     Local statistics:
      Input  bytes  :               233032
      Output bytes  :               233032
      Input  packets:                   59
      Output packets:                   59
     Transit statistics:
      Input  bytes  :                    0                    0 bps
      Output bytes  :                    0                    0 bps
      Input  packets:                    0                    0 pps
      Output packets:                    0                    0 pps
     Protocol inet, MTU: 4470, Flags: None
       Addresses, Flags: Is-Preferred Is-Primary
         Destination: 192.168.2.200, Local: 192.168.2.225, Broadcast:Unspecified
     Protocol iso, MTU: 4470, Flags: None
 
   Logical interface t3-5/2/0.1 (Index 12) (SNMP ifIndex 52)
 ...

show interfaces extensive (for T3 Interfaces)

Sample Output

 user@host> show interfaces t3-5/2/0 extensive 
 Physical interface: t3-5/2/0, Enabled, Physical link is Up
   Interface index: 30, SNMP ifIndex: 41
   Link-level type: Frame-Relay, MTU: 4474, Clocking: Internal
   Speed: T3, Loopback: None, CRC: 16, Mode: C/Bit parity
   Device flags   : Present Running
   Interface flags: Point-To-Point SNMP-Traps
   Link flags     : No-Keepalives, DCE
   Statistics last cleared: Never
   Traffic statistics:
    Input  bytes  :               268676                    0 bps
    Output bytes  :               268744                    0 bps
    Input  packets:                   68                    0 pps
    Output packets:                   68                    0 pps
   Input errors:
     Errors: 0, Drops: 0, Framing errors: 0, Policed discards: 0
     L3 incompletes: 0, L2 channel errors: 0, L2 mismatch timeouts: 0
     SRAM errors: 0, HS link CRC errors: 0
   Output errors:
     Carrier transitions: 1, Errors: 0, Drops: 0, Aged packets: 0
   Active alarms  : None
   Active defects : None
   DS3 Media:            Seconds        Count  State
     PLL Lock                  0            0  OK
     Reframing                 0            0  OK
     AIS                       0            0  OK
     LOF                       0            0  OK
     LOS                       0            0  OK
     IDLE                      0            0  OK
     YELLOW                    0            0  OK
     BPV                       0            0
     EXZ                       0            0
     LCV                       1        65535
     PCV                       0            0
     CCV                       0            0
     LES                       1
     PES                       0
     PSES                      0
     CES                       0
     CSES                      0
     SEFS                      0
     UAS                       0
   HDLC configuration:
     Policing bucket: Enabled, Bit rate:0 %, Threshold:0
     Shaping bucket : Enabled, Bit rate:0 %, Threshold:0
     Giant threshold: 4484, Runt threshold: 3
   DSU configuration:
     Compatibility mode: None, Scrambling: Disabled, Subrate: Disabled
     FEAC loopback: Inactive, Response: Disabled, Count: 0
     BERT time period: 10 seconds, Elapsed: 0 seconds
     Algorithm: 2^3 - 1, Pseudorandom (1), Error rate: 10e-0
   PFE configuration:
     Destination slot: 5, Stream number: 8, PLP byte: 1 (0x00)
     COS transmit queue bandwidth:
       Queue0: 100, Queue1: 0, Queue2: 0, Queue3: 0
     COS weighted round robin:
       Queue0: 100, Queue1: 0, Queue2: 0, Queue3: 0
  Logical interface t3-5/2/0.0 (Index 11) (SNMP ifIndex 42)
     Flags: Point-To-Point SNMP-Traps, DLCI 10, Encapsulation: FR-NLPID
     Traffic statistics:
      Input  bytes  :               268880
      Output bytes  :               268880
      Input  packets:                   68
      Output packets:                   68
     Local statistics:
      Input  bytes  :               268880
      Output bytes  :               268880
      Input  packets:                   68
      Output packets:                   68
     Transit statistics:
      Input  bytes  :                    0                    0 bps
      Output bytes  :                    0                    0 bps
      Input  packets:                    0                    0 pps
      Output packets:                    0                    0 pps
     Protocol inet, MTU: 4470, Flags: None
       Addresses, Flags: Is-Preferred Is-Primary
         Destination: 192.168.2.200, Local: 192.168.2.225, Broadcast:Unspecified
     Protocol iso, MTU: 4470, Flags: None
 
   Logical interface t3-5/2/0.1 (Index 12) (SNMP ifIndex 52)
 ...

Input Errors

The following paragraphs explain the counters that are not obvious:

• Errors
  Sum of the incoming frame aborts and FCS errors.

• Policed Discards
  Frames that the incoming packet match code discarded because they were not recognized or of interest. Usually, this field reports protocols that the JUNOS software does not handle, such as CDP.

• L3 incompletes
  This counter is incremented when the incoming packet fails Layer 3 (usually IPv4) sanity checks of the header. For example, a frame with less than 20 bytes of available IP header would be discarded and this counter would be incremented.

• L2 channel errors
  This counter increments when the software could not find a valid logical interface (that is, something like t3-1/2/3.0) for an incoming frame.

• L2 mismatch timeouts
  Count of malformed or short packets that cause the incoming packet handler to discard the frame as unreadable.

• SRAM errors
  The counter increments when a hardware error has occurred in the SRAM on the PIC. The value in this field should always be 0. If it increments, the PIC is broken.

• HS link CRC errors
  Count of errors on the high-speed links between the ASICs responsible for handling the router interfaces.

Output Errors

• Carrier transitions
  Number of times the interface has gone from down to up. This number should not increment quickly, increasing, for example, only when the cable is unplugged or the far end system is powered down and up. If it does increment quickly (perhaps, 1 every 10 seconds), then something is broken check the cable, the far end system, or the PIC.

• Errors
  Sum of the outgoing frame aborts and FCS errors.

• Drops
  Number of packets dropped by the output queue of the I/O Manager ASIC. If the interface is saturated, this number increment once for every packet that is dropped by the ASIC's RED mechanism.

• Aged packets
  Number of packets that remained in shared packet SDRAM for so long that the system automatically purged them. The value in this field should never increment. If it does, it is most likely a software bug or possible broken hardware.

Output Field Definitions

Active alarms and Active defects	T3 media-specific defects 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. Based on the router configuration, an alarm can ring the red or yellow alarm bell on the router, or the red or yellow alarm LED on the craft interface.
Addresses	Addresses associated with the logical interface.
Broadcast	The IP address for the broadcast of this interface.
Clocking	Reference clock source.
CRC	Frame checksum on the interface (either 16 or 32).
Destination	IP address of the remote side of the connection.
Device Flags	Specific information about the physical device. Possible values are described in Device Flags Field.
DLCI	If Frame Relay encapsulation is configured, the DLCI number of the logical interface.
DS3 media	Counts of T3 media-specific errors.
DSU configuration	Information about the DSU configuration. The last three lines (Bit count, Error bit count, and LOS information) are displayed only if a BERT test has ever been run on the interface.
Enabled	State of the interface. Possible values are described in Enabled Field.
Encapsulation	Encapsulation on the logical interface.
HDLC configuration	Information about the HDLC configuration.
Input rate, Output rate	The rate of bits and packets received and transmitted on the interface.
Interface Flags	Specific information about the interface. Possible values are described in Interface Flags Field.
Interface index	Physical interface's index number, which reflects its initialization sequence.
Link flags	Specific information about the links.
Link level type	Encapsulation being used on the physical interface.
Local	IP address of the logical interface.
Local statistics	Statistics for traffic received from and transmitted to the Routing Engine. When a burst of traffic is received, the value in the output packet rate field might briefly exceed the peak cell rate. It takes a while (generally, less than 1 second) for this counter to stabilize.
Logical interface, Index, SNMP ifIndex	Name of the logical interface, the logical interface's index number (which reflects its initialization sequence), and the logical interface's SNMP interface index number.
Loopback	Whether loopback is enabled and the type of loopback (local or remote).
Mode	Indicates whether or not C-bit parity mode is enabled.
MTU	MTU size on the physical interface.
PFE configuration	Information about how the Packet Forwarding Engine is configured.
Physical Interface	Name of the physical interface.
Protocol	Protocol running on the logical interface.
SNMP ifIndex	SNMP index number for the interface.
Speed	Speed at which the interface is running.
Statistics Last Cleared	Time when the statistics for the interface were last zeroed.
Traffic Statistics	Number and rate of bytes and packets received and transmitted on the physical interface.
Transit statistics	Statistics for traffic transiting the router. When a burst of traffic is received, the value in the output packet rate field might briefly exceed the peak cell rate. It takes a while (generally, less than 1 second) for this counter to stabilize.