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 OS CLI operational mode command:
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
Meaning
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
Meaning
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.
