# Monitoring the Status of Fast Ethernet Interfaces

#### Purpose

Display the status of Fast Ethernet interfaces. You can use the delta keyword to view baselined statistics. You can use the brief keyword to view the operational status of all configured interfaces.

| Note: The E120 and E320 routers output for monitor and show commands is identical to output from other E Series routers, except that the E120 and E320 router output also includes information about the adapter identifier in the interface specifier (slot/adapter/port).

#### Action

To display the status of a Fast Ethernet interface:

    host1:vr2#show interfaces fastEthernet 2/0
    FastEthernet2/0 is Up, Administrative status is Up
      Hardware is Intel 21440, address is 0090.1a10.0552
      MAU is 10BASE-T
      MTU: Operational 1518, Administrative 1518
      Duplex Mode: Operational Full Duplex, Administrative Auto Negotiate
      Speed: Operational 100 Mbps, Administrative Auto Negotiate
      De-bounce: State is Enabled, interval is 2 seconds

      5 minute input rate 0 bits/sec, 0 packets/sec
      5 minute output rate 0 bits/sec, 0 packets/sec

      In: Bytes 39256, Unicast 612
       Multicast 0, Broadcast 0
       Errors 0, Discards 0, Mac Errors 0, Alignment 0
       CRC 0, Too Longs 0, Symbol Errors 0
      Out: Bytes 4579036, Unicast 610
       Multicast 0, Broadcast 70932
       Errors 0, Discards 0, Mac Errors 0, Deferred 0, No Carrier 3
       Collisions: Single 0, Multiple 0, Late 0, Excessive 0
     ARP Statistics:
      In: ARP requests 0, ARP responses 0
       Errors 0, Discards 0
      Out: ARP requests 0, ARP responses 0
       Errors 0, Discards 0
    Administrative qos-shaping-mode: none
    Operational qos-shaping-mode: none

    queue 0: traffic class control, bound to FastEthernet2/0
      Queue length 0 bytes
      Forwarded packets 1, bytes 46
      Dropped committed packets 0, bytes 0
      Dropped conformed packets 0, bytes 0
      Dropped exceeded packets 0, bytes 0

#### Meaning

Table 25 lists the show interfaces fastEthernet command output fields.

Table 25: show interfaces fastEthernet Output Fields

Field Name | Field Description
--- | ---
FastEthernet interfaceSpecifier— | Status of the hardware on this interface: up—Hardware is operational down—Hardware is not operational
Administrative status | Operational state that you configured for this interface: up—Interface is enabled down—Interface is disabled
Hardware | Type of MAC device on this interface
Address | MAC address of the processor on this interface
MAU | Type of medium attachment unit (MAU) on the physical port: 10BASE-T (10 Mbps) 100BASE-TX (100 Mbps) 100BASE-FX-MM (100 Mbps) with the distance appearing after the type 100BASE-LX-SM (100 Mbps) SFP (Empty)—SFPs that are empty SFP (Non-compliant Juniper Part)—SFPs that are installed in the FE-8 I/O module and do not have a Juniper Networks part number programmed
MTU | Size of the MTU for this interface: Operational—Size of the largest packet processed Administrative—Setting for MTU size that you specified
Duplex Mode | Duplex option for this interface: Operational—Duplex option currently used Administrative—Setting for duplex that you specified
Speed | Line speed for this interface: Operational—Current rate at which packets are processed Administrative—Setting for line speed 5 minute input rate—Data rates based on traffic received in the last 5 minutes 5 minute output rate—Data rates based on traffic sent in the last 5 minutes
De-bounce | Debounce configuration for this interface: State is—Enabled, Disabled Interval is—Number of seconds that this interface maintains a given state before the state change is reported to the upper-layer links
In | Analysis of inbound traffic on this interface: Bytes—Number of bytes received in error-free packets Unicast—Number of unicast packets received Multicast—Number of multicast packets received Broadcast—Number of broadcast packets received Errors—Total number of errors in all received packets; some packets might contain more than one error Discards—Total number of discarded incoming packets Mac Errors—Number of incoming packets discarded because of MAC sublayer failures Alignment—Number of incomplete octets received CRC—Number of packets discarded because the checksum the router computed from the data does not match the checksum generated by the originating devices Too Longs—Number of packets discarded because the size exceeded the MTU Symbol Errors—Number of symbols received that the router did not correctly decode
Out | Analysis of outbound traffic on this interface: Bytes—Number of bytes sent Unicast—Number of unicast packets sent Multicast—Number of multicast packets sent Broadcast—Number of broadcast packets sent Errors—Total number of errors in all transmitted packets; some packets might contain more than one error Discards—Total number of discarded outgoing packets Mac Errors—Number of outgoing packets discarded because of MAC sublayer failures Deferred—Number of packets that the router delayed sending because the line was busy. In half duplex mode, a high number of deferrals means the link is very busy with traffic from other stations. In full duplex mode, when the link is always available for transmission, this number is zero. No Carrier—Number of packets sent when carrier sense was unavailable
Collisions | Analysis of the collisions that occurred: Single—Number of packets sent after one collision Multiple—Number of packets sent after multiple collisions Late—Number of packets aborted during sending because of collisions after 64 bytes Excessive—Number of packets not sent because of too many collisions
ARP Statistics | Analysis of ARP traffic on this interface; In fields are for traffic received on the interface and Out fields are for traffic sent on the interface: ARP requests—Number of ARP requests ARP responses—Number of ARP responses Errors—Total number of errors in all ARP packets Discards—Total number of discarded ARP packets
queue | Hardware packet queue associated with the specified traffic class and interface: Queue length—Length of the queue, in bytes Forwarded packets, bytes—Number of packets and bytes that were forwarded on this queue Dropped committed packets, bytes—Number of committed packets and bytes that were dropped Dropped conformed packets, bytes—Number of conformed packets and bytes that were dropped Dropped exceeded packets, bytes—Number of exceeded packets and bytes that were dropped

#### Related Documentation

- Configuring the Physical Interface
- Monitoring the Status of Gigabit Ethernet and 10-Gigabit Ethernet Interfaces
- Setting Statistics Baselines for Ethernet Interfaces
- show interfaces