CLI Commands for Ethernet Traffic

The show interface Ethernet x/y command gives complete performance data of a given Ethernet interface. It not only shows the number of octets and frames, but also the interface load, an averaged throughput, and much other data.

Example 13-1 provides sample output for the show interface Ethernet x/y command.

Example 13-1 Using show interface Ethernet x/y to evaluate Ethernet traffic.

 nms-7010a#sh int fa0/0 FastEthernet0/0 is up, line protocol is up  Hardware is cyBus FastEthernet Interface, address is 0060.5490.f800 (bia 0060.5490.f800)  MTU 1500 bytes, BW 100000 KbitA, DLY 100 usec, rely 255/255, load 1/255B  Encapsulation ARPA, loopback not set, keepalive set (10 sec), fdxC, 100BaseTX/FX  ARP type: ARPA, ARP Timeout 04:00:00  Last input 00:00:01, output 00:00:01, output hang never Last clearing of "show interface" counters 00:43:40D  Queueing strategy: fifo  Output queue 0/40, 0 drops; input queue 0/75, 0 drops  5 minute input rate 2376 bits/sec, 27 packets/sec  5 minute output rate 1000 bits/sec, 7 packets/sec   3653980 packets input, 269895525 bytesE, 0 no buffer   Received 3499 broadcasts, 0 runts, 0 giants   1119 input errors, 1119 CRC, 540 frame, 0 overrun, 0 ignored, 0 abort   0 watchdog, 744 multicast   0 input packets with dribble condition detected   1507771 packets output, 161101301 bytes, 0 underruns   0 output errors, 0 collisions, 2 interface resets   0 babbles, 0 late collision, 0 deferred   0 lost carrier, 0 no carrier   0 output buffer failures, 0 output buffers swapped out 

The highlighted information in Example 13-1 is as follows:

A BW is the bandwidth of the interface.

B Load indicates a five-minute sliding average of the traffic load on the interface expressed as a fraction of 255. The average is calculated using the formula for a five-minute sliding average, as explained in Chapter 7, "Understanding and Using Basic Network Statistics."

C FDX indicates that the interface is full-duplex. For interfaces capable of only half-duplex operation, this data is not displayed. You can assume that if the mode is not explicitly stated in the show interface output, it is in half-duplex mode.

D The Last clearing of show interface counters shows the last time the clear counters command was executed. It does no good to know that 1000 bytes have been received if you do not know how long it took to receive them.

E The 5-minute bit and packet rates are calculated using a 5-minute sliding averaging algorithm, as explained in "Moving Exponential Average for Cisco Routers CPU Calculation" in Chapter 7. Also present are the total byte or packet counts.

For Catalyst switches, the show mac command gives you raw performance data, showing the number of octets and frames as well as the type of frames: unicast, broadcast, or multicast. This command is illustrated in Example 13-2.

Example 13-2 Using show mac x/y to obtain performance data for Ethernet traffic.

 nms-5500a> (enable) show mac 4/2 MAC      Rcv-Frms   Xmit-Frms   Rcv-Multi  Xmit-Multi Rcv-Broad  Xmit-Broad -------- ---------- ----------  ---------- ---------- ---------- ----------  4/2     124553     623141      11715      464879     22         90320 MAC      Dely-Exced MTU-Exced  In-Discard  Lrn-Discrd  In-Lost    Out-Lost -------- ---------- ---------- ----------  ----------  ---------- ----------  4/2     0          0          0           0           0          0 Port     Rcv-Unicast          Rcv-Multicast        Rcv-Broadcast -------- -------------------- -------------------- --------------------  4/2     112816               11715                22 Port     Xmit-Unicast         Xmit-Multicast       Xmit-Broadcast -------- -------------------- -------------------- --------------------  4/2     67942                464879               90320 Port     Rcv-Octet            Xmit-Octet -------- -------------------- --------------------  4/2     20344641             49348209 Last-Time-Cleared -------------------------- Fri Jan 22 1999, 15:07:39 

Note that for switch software versions 2.x, you only can get frame counts with show mac x/y. For switch software versions 3.x and higher, you can see both frame and octet counts.

The show counters x/y can be a useful command. It generates a complete dump of all the mac and port counters for the switch. Here, you will see the counters from the show mac and the show port command as well as SNMP counters from RFC 1757 (RMON MIB) and RFC 2358 (dot3 MIB). Please refer to Example 13-3.

Example 13-3 Using the show counters command to obtain all the mac and port counters for the switch.

 nms-5505a (enable) sh counters 1/1 64 bit counters 0 ifHCInOctets     =   29477694204 1 ifHCInUcastPkts    =     0 2 ifHCInMulticastPkts   =   120599698 3 ifHCInBroadcastPkts   =     0 4 ifHCOutOctets    =   26516883506 5 ifHCOutUcastPkts    =     0 6 ifHCOutMulticastPkts   =   143919486 7 ifHCOutBroadcastPkts   =     0 32 bit counters 0 etherStatsFragments   =   1 1 dot3StatsInternalMacRxErrs =   1 2 etherStatsJabbers   =   0 3 baseX100StatsSymCodeViolates =   0 4 dot1BasePortDelayExcdAborts =   0 5 badTxCRC      =   0 6 dot3StatsLateCollisions  =   0 7 dot3StatsExcessiveCollisions =   0 8 dot3StatsSQETestErrors  =   0 9 dot3StatsCarrierSenseErrors =   0 10 dmaOverflow     =   0 11 linkFail      =   26 12 txJabber      =   0 13 dmaTxLengthErrors   =   0 14 dmaRxLengthErrors   =   0 15 dmaXferLengthErrors   =   0 16 dmaMonitorPkts    = 40960399 17 dot1dTpPortInFrames   = 120599700 18 dot3StatsFCSErrors   =   0 19 dot1dTpPortOutFrames   = 143919491 20 dot3StatsSingleColFrames  =   0 21 dot3StatsMultiColFrames  =   0 22 dot3StatsInternalMacTxErrs =   0 23 dot3StatsDeferredTx   =   0 24 dot3StatsBadPreamble   =   0 25 dot3StatsAbortLateCollision =   0 26 dot3StatsABortExcessiveLen =   0 27 dot1dTpPortInDiscards  =  125 28 rxRuntErrors     =   0 29 dmaMacMismatch    =   10 30 etherStatsRxPkts256to511  = 13384238 31 etherStatsRxPkts512to1023 = 3024640 32 etherStatsRxPkts1024to1518 = 3203146 33 etherStatsOversizePkts  =   0 34 dot3StatsAlignmentErrors  =   0 35 etherStatsRxMulticastPkts = 120599700 36 etherStatsRxBroadcastPkts =   0 37 etherStatsTxPkts64   =   8 38 etherStatsTxPkts65to127  = 50334315 39 etherStatsTxPkts128to255  = 79605022 40 etherStatsTxPkts256to511  = 10598850 41 etherStatsTxPkts512to1023 = 1827874 42 etherStatsTxPkts1024to1518 =  180548 43 dmaLastChance    =   0 44 etherStatsRxPkts65to127  = 35634715 45 etherStatsRxPkts128to255  = 63332105 46 etherStatsTxBroadcastPkts =   0 47 etherStatsTxMulticastPkts = 143919491 48 etherStatsRxOctets   = 3707890908 49 etherStatsTxOctets   = 747080475 50 dmaTxFull     =   0 51 dmaRetry      =   0 52 dmaLevel2Request    =   0 53 etherStatsUndersizePkts  =   0 54 dot3StatsTotalCollisions  =   0 55 etherStatsRxPkts64   =   9