Verify That the Fast Ethernet or Gigabit Ethernet Interface Is Up
Display the status of the Fast Ethernet or Gigabit Ethernet interface to provide the information you need to determine whether the physical link is up or down.
To verify that the status of the Fast Ethernet or Gigabit Ethernet interface is up, use the following Junos OS command-line interface (CLI) operational mode command:
user@host# show interfaces ge-4/0/6 extensive
Physical interface: ge-4/0/6, Enabled, Physical link is Up Interface index: 144, SNMP ifIndex: 516, Generation: 147 Link-level type: Ethernet, MTU: 1514, Speed: 1000mbps, BPDU Error: None, MAC-REWRITE Error: None, Loopback: Enabled, Source filtering: Disabled, Flow control: Enabled, Auto-negotiation: Enabled, Remote fault: Online Device flags : Present Running Loop-Detected Interface flags: SNMP-Traps Internal: 0x4000 Link flags : None CoS queues : 8 supported, 4 maximum usable queues Schedulers : 0 Hold-times : Up 0 ms, Down 0 ms Current address: 00:1f:12:fe:c5:2e, Hardware address: 00:1f:12:fe:c5:2e Last flapped : 2015-01-20 23:40:04 PST (00:02:12 ago) Statistics last cleared: Never Traffic statistics: Input bytes : 0 0 bps Output bytes : 0 0 bps Input packets: 0 0 pps Output packets: 0 0 pps IPv6 transit statistics: Input bytes : 0 Output bytes : 0 Input packets: 0 Output packets: 0 Dropped traffic statistics due to STP State: Input bytes : 0 Output bytes : 0 Input packets: 0 Output packets: 0 Input errors: Errors: 0, Drops: 0, Framing errors: 0, Runts: 0, Policed discards: 0, L3 incompletes: 0, L2 channel errors: 0, L2 mismatch timeouts: 0, FIFO errors: 0, Resource errors: 0 Output errors: Carrier transitions: 1, Errors: 0, Drops: 0, Collisions: 0, Aged packets: 0, FIFO errors: 0, HS link CRC errors: 0, MTU errors: 0, Resource errors: 0 Egress queues: 8 supported, 4 in use Queue counters: Queued packets Transmitted packets Dropped packets 0 best-effort 0 0 0 1 expedited-fo 0 0 0 2 assured-forw 0 0 0 3 network-cont 0 0 0 Queue number: Mapped forwarding classes 0 best-effort 1 expedited-forwarding 2 assured-forwarding 3 network-control Active alarms : None Active defects : None MAC statistics: Receive Transmit Total octets 0 0 Total packets 0 0 Unicast packets 0 0 Broadcast packets 0 0 Multicast packets 0 0 CRC/Align errors 0 0 FIFO errors 0 0 MAC control frames 0 0 MAC pause frames 0 0 Oversized frames 0 Jabber frames 0 Fragment frames 0 VLAN tagged frames 0 Code violations 0 Filter statistics: Input packet count 0 Input packet rejects 0 Input DA rejects 0 Input SA rejects 0 Output packet count 0 Output packet pad count 0 Output packet error count 0 CAM destination filters: 0, CAM source filters: 0 Autonegotiation information: Negotiation status: Complete Link partner: Link mode: Full-duplex, Flow control: Symmetric/Asymmetric, Remote fault: OK Local resolution: Flow control: Symmetric, Remote fault: Link OK Packet Forwarding Engine configuration: Destination slot: 4 CoS information: Direction : Output CoS transmit queue Bandwidth Buffer Priority Limit % bps % usec 0 best-effort 95 950000000 95 0 low none 3 network-control 5 50000000 5 0 low none Interface transmit statistics: Disabled
The sample output shows that the link is up and there are no alarms in this loopback configuration. When an internal loopback is configured, the physical loopback should come up without an alarm.
When you see that the physical link is down, there may be a problem with the port. The following output is an example of the show interfaces fe-fpc/pic/port command when the physical link is down:
user@router> show interfaces fe-1/3/0 Physical interface: fe-1/3/0, Enabled, Physical link is Down Interface index: 44, SNMP ifIndex: 35 Link-level type: Ethernet, MTU: 1514, Source filtering: Disabled Speed: 100mbps, Loopback: Disabled, Flow control: Enabled Device flags : Present Running Down Interface flags: Hardware-Down SNMP-Traps Link flags : None Current address: 00:90:69:8d:2c:db, Hardware address: 00:90:69:8d:2c:db Input rate : 0 bps (0 pps), Output rate: 0 bps (0 pps) Active alarms : LINK Active defects : LINK MAC statistics: Input octets: 0, Input packets: 0, Output octets: 0, Output packets: 0 Filter statistics: Filtered packets: 0, Padded packets: 0, Output packet errors: 0 Autonegotiation information: Negotiation status: Incomplete, Link partner status: Down Reason: Link partner autonegotiation failure Link partner: Half-duplex, Flow control: None
The sample output shows that the physical link is down and there are active alarms and defects.
Table 1 presents problem situations and actions for a physical link that is down.
Table 1: Problems and Solutions for a Physical Link That Is Down
Verify that the fiber connection is correct.
Damaged and/or dirty cable
Verify that the fiber can successfully loop a known good port of the same type.
Too much or too little optical attenuation
Verify that the attenuation is correct per the PIC optical specifications.
The transmit port is not transmitting within the dBm optical range per the specifications
Verify that the Tx power of the optics is within range of the PIC optical specification.
Mismatch between the cable type and the port
Verify that a single-mode fiber cable is connected to a single-mode interface and that a multimode fiber cable is connected to a multimode interface. (This problem does not always cause the physical link to go down; errors and dropped packets are sometimes the result.)