Step 3: Verify That the T3 Interface Is Up

Purpose

Display the status of the T3 interface to provide the information you need to determine whether the physical link is up or down.

Action

To verify that the status of the T3 interface is up, use the following JUNOS CLI operational mode command:

user@host> show interfaces t3-fpc/pic/port

Sample Output

The following output is for a T3 interface with the physical link up:

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

Physical interface: t3-1/0/0, Enabled, Physical link is Up

  Interface index: 9, SNMP ifIndex: 10

  Link-level type: PPP, MTU: 4474, Clocking: Internal

  Speed: T3, Loopback: None, CRC: 16, Mode: C/Bit parity

  Device flags   : Present Running Loop-Detected

  Interface flags: Link-Layer-Down Point-To-Point SNMP-Traps

  Link flags     : Keepalives

  Keepalive Input: 6684 (00:07:51 ago), Output: 6693 (00:06:41 ago)

  NCP state: Down, LCP state: Conf-req-sent

  Input rate     : 224 bps (2 pps), Output rate: 240 bps (2 pps)

  Active alarms  : None

  Active defects : None

  Logical interface t3-1/0/0.0 (Index 13) (SNMP ifIndex 32)

    Flags: Device-down Hardware-Down Point-To-Point SNMP-Traps

    Encapsulation: PPP

    Protocol inet, MTU: 4470, Flags: Protocol-Down

      Addresses, Flags: Dest-route-down Is-Preferred Is-Primary

        Destination: 1.1.1.0/30, Local: 1.1.1.1 

What It Means

The sample output shows that the physical link is up, the loop is detected, and there are no T3 alarms or defects.

Sample Output

If the physical link is down, there may be a problem with the port. The following output is an example of the show interfaces t3-fpc/pic/port command when the physical link is down:

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

Physical interface: t3-1/0/0, Enabled, Physical link is Down

  Interface index: 9, SNMP ifIndex: 10

  Link-level type: Cisco-HDLC, MTU: 4474, Clocking: Internal

  Speed: T3, Loopback: None, CRC: 16, Mode: C/Bit parity

  Device flags   : Present Running Down

  Interface flags: Hardware-Down Link-Layer-Down Point-To-Point SNMP-Traps

  Link flags     : Keepalives

  Keepalive Input: 116 (00:02:32 ago), Output: 185 (00:00:02 ago)

  Input rate     : 0 bps (0 pps), Output rate: 0 bps (0 pps)

  Active alarms  : LOF, LOS

  Active defects : LOF, LOS

  Logical interface t3-1/0/0.0 (Index 12) (SNMP ifIndex 32)

    Flags: Device-down Point-To-Point SNMP-Traps, Encapsulation: Cisco-HDLC

    Protocol inet, MTU: 4470

      Addresses, Flags: Dest-route-down Is-Preferred Is-Primary

        Destination: 1.1.1.0/30, Local: 1.1.1.1

What It Means

The sample output shows that the physical link is down, the device flags and interface flags are down, and that there are T3 alarms and defects. Verify that the fiber can successfully loop a known good port of the same type by checking for damage to the cable.