Show Interface Command Output

35 pts.
Tags:
Cisco
Cisco IOS
Routers
Can anybody interprete "show interface" command output on cisco routers?

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Show Interface Command Output Interpretation:

<b>[Router1#sh int Serial3/0/3:1 </b> (show interface command)
<b>Serial3/0/3:1 is up, line protocol is up </b> Serial interface is up, line protocol is up (line is working ok)
<b>Hardware is PA-MC-2T3+ </b> Type of hardware the serial interface is connected to
<b>Description: Customer T1 </b> Description set by Network Admin
<b>Internet address is x.x.x.x/30</b> (IP address and subnet mask assigned to the serial interface
<b>MTU 1500 bytes, BW 256 Kbit, DLY 20000 usec,</b>
MTU – Maximum Tranmission Unit. By default, this is 1500 bytes, which describes the largest packet that can be sent through the interface before the packet is fragmented.
BW – Bandwidth. This field is defined by the network administrator and has no actual effect on the bandwidth of a line. It is simply used for describing the load on a specific interface.
DLY – Delay. Amount of micro seconds of delay. I do not have any more information on this at this time.
rely – Reliability. Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over five minutes (default).
load – Load Average. Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over five minutes (default).
<b>rely 255/255, load 1/255 </b> rely – Reliability. Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over five minutes (default).
load – Load Average. Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over five minutes (default).
Encapsulation PPP, crc 16, loopback not set Encapsulation is the type of Data-Link encapsulation. This is commonly either PPP, HDLC (Cisco’s proprietary PPP), Frame-Relay, and ATM.
Loopback specifies whether the loopback bit is set in the D channel signaling. )

<b>Keepalive set (10 sec) </b> (The time in seconds between successive keepalive requests. The
range is 10 seconds through 32767 seconds, with a default of 10 seconds)

<b>LCP Open</b> (LCP(Link Control Protocol) is in Opened state)
<b>Open: IPCP, CDPCP </b> (IPCP(IP Control Protocol) is protocol that establishes and configures
IP over PPP is in Open state.
CDPCP(Cisco Discovery Protocol Control Protocol) is in Open state)

<b>Last input 00:00:03, output 00:01:08, output hang never</b> (The last input is the number of hours(00), minutes(00), and seconds(03) since the last packet was successfully received by an interface. This is useful for determining when a dead interface.
The last output is the number of hours (00), minutes (01), and seconds (08) since the last packet was successfully transmitted by an interface. This is useful for determining when a dead interface failed.
The output hang is the number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long.)
<b>Last clearing of “show interface” counters never </b> (This shows the elapsed time, in seconds, since the last clearing of the interface counters.)
Input queue: 0/75/0 (size/max/drops); Total output drops: 0 There is (0 Packets in input queue, input queue has max capacity to
accommodate 75 packets; input queue has dropped 0 packets. Output drops can be caused when the output media cannot accept frames and the output queue reaches the maximum value before it starts dropping packets. Output drops may not necessarily indicate a problem since an explorer frame being dropped because it has already traveled on a particular ring can increment the output drops counter. Increasing input drops on the other hand, can be serious and should be looked into carefully. Input drops can be caused by insufficient system buffers – see 0 no buffer in the show interfaces tokenRing 0 output above. The incrementing no buffer counter of the show interfaces output may correlate to the incrementing misses counter of the show buffers output, and the appropriate buffer pool may need to be tuned.)

<b>Queueing strategy: weighted fair </b> (Weighted fair queuing (WFQ) enables slow-speed links, such as
serial links, to provide fair treatment for all types of traffic. It classifies the traffic into different flows (also known as conversations) based on layer three and layer four information, such as IP addresses and TCP ports. It does this without requiring you to define access lists. This means that low-bandwidth traffic effectively has priority over high-bandwidth traffic because high-bandwidth traffic shares the transmission media in proportion to its assigned weight.)

<b>Output queue: 0/1000/64/0 (size/max total/threshold/drops)</b> (There are 0 packets in output queue, it has capacity to accommodate
1000 packets with threshold of 64 packets, it has dropped 0 packets, Number of packets in output queue. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue.)

<b>Conversations 0/1/256 (active/max active/max total) </b> (It gives queue information)
Reserved Conversations 0/0 (allocated/max allocated) (It gives queue information)
5 minute input rate 0 bits/sec, 0 packets/sec (Average number of bits and packets received per
second in the last five minutes.)
5 minute output rate 0 bits/sec, 0 packets/sec (Average number of bits and packets transmitted per
second in the last five minutes.)

<b>20950 packets input, 1992090 bytes, 0 no buffer</b> (Total number of error-free packets received (20950), bytes
(1992090))

<b>Received 0 broadcasts, 0 runts, 0 giants, 0 throttles </b> (Total number of broadcast or multicast packets (0) received
Runts – Number of packets (0) discarded because they are smaller
than the medium’s minimum packet size.
Giants – Number of packets (0) that are discarded because they exceed the medium’s maximum packet size.
Throttle – This counter indicates the number of times (0) the input buffers of an interface have been cleaned because they have not been serviced fast enough or they are overwhelmed. Typically, an explorer storm can cause the throttles counter to increment. It’s important to note that every time you have a throttle; all the packets in the input queue get dropped. This causes very slow performance and may also disrupt existing sessions. )
<b>1 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 1 abort</b> (Input Errors (1) – Sum of all errors that prevented the receipt of datagrams. This may not balance with the sum of the enumerated output errors, because some datagrams may have more than one error and others may have errors that do not fall into any of the specific categories.
CRC (0) – Cyclic redundancy checksum generated mismatch. CRC errors also are reported when a far-end abort occurs and when the idle flag pattern is corrupted. This makes it possible to get CRC errors even when there is no data traffic.
Frame (0) – Number of packets received incorrectly having a CRC error and a noninteger number of octets.
Overrun (0) – Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver’s ability to handle the data.
Ignored (0)- Number of received packets ignored by the interface because the interface hardware ran low on internal buffers.
Abort (1) – Number of packets whose receipt was aborted. )
<b>31524 packets output, 10804297 bytes, 0 underruns</b> (31524 packets and 10804297 bytes have been transmitted by the
System.
Underruns – Number of times that the far-end router’s transmitter has been running faster than the near-end router’s receiver can handle. This may never happen (be reported) on some interfaces. )
<b>0 output errors, 0 collisions, 0 interface resets Output Errors (0)</b> (Sum of all errors that prevented the final transmission. This may not balance with the sum of the enumerated output errors, because some datagrams may have more than one error and others may have errors that do not fall into any of the specific categories. )
Packet collisions (0)
Interface Resets (0) (Number of times an interface has been completely reset.
<b>0 output buffer failures, 0 output buffers swapped out</b> Failures (0)- identifies the number of failures to grant a buffer to a requester even after an attempt to create an additional buffer is made. The number of failures represents the number of packets that have been dropped due to buffer shortages.
<b>0 carrier transitions no alarm present </b> Carrier Transitions – Number of times the carrier detect signal of a serial interface has changed state. )
<b>Timeslot(s) Used: 1-4, subrate: 256Kb/s, transmit delay is 0 flags</b>

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