Monitor Statistics for a Fast Ethernet or Gigabit Ethernet Interface
Learn about how to monitor real-time statistics on Fast Ethernet and Gigabit Ethernet interfaces.
Purpose
To monitor statistics for a Fast Ethernet or Gigabit Ethernet interface, use the following Junos OS CLI operational mode command:
Action
user@host> monitor interface (fe-fpc/pic/port| ge-fpc/pic/port)
We recommend that you use the monitor interface fe-fpc/pic/port
or monitor interface ge-fpc/pic/port
command only for diagnostic purposes. Do not leave these commands on during normal
router operations because real-time monitoring of traffic consumes additional CPU and memory
resources.
Sample Output
The following sample output is for a Fast Ethernet interface:
user@host> monitor interface fe-2/1/0 Interface: fe-2/1/0, Enabled, Link is Up Encapsulation: Ethernet, Speed: 100mbps Traffic statistics: Current Delta Input bytes: 282556864218 (14208 bps) [40815] Output bytes: 42320313078 (384 bps) [890] Input packets: 739373897 (11 pps) [145] Output packets: 124798688 (1 pps) [14] Error statistics: Input errors: 0 [0] Input drops: 0 [0] Input framing errors: 0 [0] Policed discards: 6625892 [6] L3 incompletes: 75 [0] L2 channel errors: 0 [0] L2 mismatch timeouts: 0 [0] Carrier transitions: 1 [0] Output errors: 0 [0] Output drops: 0 [0] Aged packets: 0 [0] Active alarms : None Active defects: None Input MAC/Filter statistics: Unicast packets 464751787 [154] Packet error count 0 [0]
Meaning
Use the information from this command to help narrow down possible causes of an interface problem.
If you are accessing the router from the console connection, make sure you set the CLI
terminal type using the set cli terminal command.
The second column shows cumulative statistics since the last time you cleared them using
the clear interfaces statistics interface-name command. The third column
shows cumulative statistics since you ran the monitor interface
interface-name command. If input errors are increasing, follow these steps:
-
Check the cabling to the router and ask the carrier to verify the line’s integrity. Ensure you are using the correct cables for the interface port—single-mode fiber for a single-mode interface, and multimode fiber for a multimode interface.
-
For fiber-optic connections, measure the received light level at the receiver end and ensure it meets the Ethernet interface’s specification.
-
Measure the transmit light level on the Tx port to confirm it is within the specified range.