1 2 3 Previous Next 36 Replies Latest reply: May 29, 2013 12:54 AM by Dan RSS

    Interface Bandwidth Utilization calculation method

    Parveen

      HI team,

       

      i just want to know how i check interface over utilization and also wants to check how much a BW is utilizing in my network for this i don't wana use any monitoring tool suppose when i run command

       

      SHOW INTERFACE F0/0 and check 5 min input and output rate is

       

      5 minute input rate 72000 bits/sec, 37 packets/sec

      5 minute output rate 334000 bits/sec, 41 packets/sec

       

      so how can we calculate from above output that is it over utlizing or it is normal.pls clear it to me with example and formula use to calculate the utilization

        • 1. Re: Interface Bandwidth Utilization calculation method
          Chad Spears CCNP CCDA CCNAS

          Parveen-

           

          First I would suggest setting the load-interval to 30 seconds, this will give you a better representation of the bandwidth at the times you are issuing the command.  Can you set the load interval by issuing the "load-internal 30" interface command.

           

          Below you will see how we can use the show interface command to determine bandwidth utilization:

           

          WRMC-MC-RT-100-1#show int fa0/0

          FastEthernet0/0 is up, line protocol is up

            Description: LINK TO CHARTER | METRO-E TO CHS

            MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,

               reliability 255/255, txload 1/255, rxload 1/255

            30 second input rate 0 bits/sec, 1 packets/sec

            30 second output rate 1000 bits/sec, 1 packets/sec

               145488249 packets input, 1891788591 bytes

               Received 457 broadcasts, 0 runts, 0 giants, 48 throttles

               48 input errors, 0 CRC, 0 frame, 0 overrun, 48 ignored

               0 watchdog

               0 input packets with dribble condition detected

               143822386 packets output, 860392112 bytes, 0 underruns

           

          As you can see on my 100mbit interface I am currently using 1kbit/sec output and 0kbit/sec input on an average over the last 30 seconds.  This is almost no traffic.... (which it is early morning here, so no one in the office yet )

           

          However, you can use this command to monitor the bandwidth.  Some things to remember are:  If you are monitoring a "leased line" you may want to set the interface bandwidth using the "bandwidth" interface command.  Remember routing protocols will use the bandwidth to calculate the best path.  By setting the bandwidth to the accurate interface bandwidth it will help you monitor closer.

           

          Also, note the txload and rxload output.  This is a representation of the the interface utilization based on the bandwidth, input rate, and output rate calculations.

           

          HTH,
          CS

          • 2. Re: Interface Bandwidth Utilization calculation method
            Parveen

            Chad Spears

             

            thanks for reply.as per u said ur interface f0/0 5 min output rate is 1000 bits/sec okay but m saying in my case output of 5 min rate is

             

            5 minute input rate 72000 bits/sec, 37 packets/sec

            5 minute output rate 334000 bits/sec, 41 packets/sec

             

            and my bandwidth is 256 kb now tell me is it over utilizing or its normal and pls tell me how u calculate it.

            • 3. Re: Interface Bandwidth Utilization calculation method
              cadetalain

              Hi,

               

              on a Fastethernet interface having 72 kbs and 334 kbs is not overutilization, don't forget that the bandwidth command is only used by some routing protocols( EIGRP,OSPF) and by QoS tools like CBWFQ or LLQ,.

              To see the overutilization you should consider the physical speed of the interface which is 100Mbs here and compare the outputs you showed us but with a lower load-interval and also look at the packet drops on the interface

               

              Regards.

               

              Alain

              • 4. Re: Interface Bandwidth Utilization calculation method
                Chad Spears CCNP CCDA CCNAS

                Parveen-

                 

                Notice my output is in 30 second intervals, not 5 mins.  This will allow you to calculate the interface utlization easier.  Can you post your entire show interface output?

                 

                Just looking at the output... it doesnt appear you are over utilizing.  It appears that your ouput rate is actually around 1kbit/sec.

                 

                HTH,

                CS

                • 5. Re: Interface Bandwidth Utilization calculation method
                  Parveen

                  Hi Chad Spears

                   

                  below is my output and my WAN bandwidth is 256 KB only. now pls tell me is it over utilizing and how u calculate above thats oits not over utilizing means u say 32 kb/sec all i want to learn this calculation as well

                   

                   

                  FastEthernet0/0 is up, line protocol is up

                    Hardware is Gt96k FE, address is 001d.e60b.0a26 (bia 001d.

                      Internet address is 192.168.8.1/24

                    MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

                       reliability 255/255, txload 1/255, rxload 1/255

                    Encapsulation ARPA, loopback not set

                    Keepalive set (10 sec)

                    Full-duplex, 100Mb/s, 100BaseTX/FX

                    ARP type: ARPA, ARP Timeout 04:00:00

                    Last input 00:00:01, output 00:00:00, output hang never

                    Last clearing of "show interface" counters 05:57:38

                    Input queue: 0/75/0/0 (size/max/drops/flushes); Total outp

                    Queueing strategy: fifo

                    Output queue: 0/40 (size/max)

                    5 minute input rate 529000 bits/sec, 35 packets/sec

                    5 minute output rate 742000 bits/sec,40 packets/sec

                       568283 packets input, 165463931 bytes

                       Received 3970 broadcasts, 0 runts, 0 giants, 0 throttle

                       0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

                       0 watchdog

                       0 input packets with dribble condition detected

                       596783 packets output, 453850117 bytes, 0 underruns

                       0 output errors, 0 collisions, 0 interface resets

                       0 babbles, 0 late collision, 0 deferred

                       0 lost carrier, 0 no carrier

                       0 output buffer failures, 0 output buffers swapped out

                  • 6. Re: Interface Bandwidth Utilization calculation method
                    Brian

                    Keep in mind setting a lower interval will give you input and output statistics that are based on more instantaneous data.  Meaning it is more reactive to short bursts of traffic.  Not a good representation of the overall load on an interface.  Why?  Because when you set the interval low (30 seconds) as suggested, it is more reactive to small bursts of traffic, from say routing protocol updates or web page down loads.  When determining if the load on your interface is over utilized, you want to use a high interval (5 minute avg).  You then would take several outputs of the "sh interface" and if your 5 min avg are consistently above 70% then your link is over utilized.  You want to make sure the load on any interface does not exceed more then 70% for long periods of time.  Short bursts are acceptable and normal.  Long periods with consistently high averages are not.

                     

                    Hope this helps.

                     

                    Brian

                     

                    • 7. Re: Interface Bandwidth Utilization calculation method
                      Brian

                      A BW of 256KB is 2Mbps (Bytes x 8 = bits).  Is the FE port the connection to your WAN?  Or do you have a serial port configured for say 256kbps?

                       

                      Based on your Tx and Rx load, no you are not over utilized.

                       

                      FastEthernet0/0 is up, line protocol is up

                        Hardware is Gt96k FE, address is 001d.e60b.0a26 (bia 001d.

                          Internet address is 192.168.8.1/24

                        MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

                           reliability 255/255, txload 1/255, rxload 1/255

                       

                      Brian

                       

                       

                      Message was edited by: Brian

                      • 8. Re: Interface Bandwidth Utilization calculation method
                        arteq

                        great info...

                        • 9. Re: Interface Bandwidth Utilization calculation method
                          Parveen

                          Brian

                           

                          thanks i was waiting for your response.now i know low reate is good to TSHOOT actually i wants to learn the concept so i can TSHOOT these kind of issue easy in my network. so pls explain with concise way more details. as u said i am connected to WAN with fast interface and my WAN link BW is 256 Kb only and Brian i exactly wnat to know as u said by looking my TX and Rx load how u determine the formula you use to calculte that my TX and RX value so no over utilizing and second thing apart from this how thiese value also use to calculate over utlization check by 5 min or take 30 sec. input rate

                           

                          5 minute input rate 529000 bits/sec, 35 packets/sec

                            5 minute output rate 742000 bits/sec,40 packets/sec

                           

                           

                          Brian

                           

                          u said 2560 Kb is 2MB how as per my calculation if m not doing wrong it would be 2.5Mb (2560kb/1000 mb = 2.5Mb).pls correct this

                          • 10. Re: Interface Bandwidth Utilization calculation method
                            Brian

                            That should be 256KB.  Typo on my part, sorry.  If you are connected to the WAN with a FE how is your BW only 256kb?  Please describe your setup a bit more.

                             

                            Brian

                             

                            • 11. Re: Interface Bandwidth Utilization calculation method
                              Parveen

                              Brian

                               

                              we take 256 Kb WAN connection becoz our branch office has only 5 user and second thing Brian i wanthere to learn the trick of tsHOOT BY SHOW INTERFACE F0/0 OUTPUT FOR FUTURE PROBLEMS IF CAME

                               

                              as u said by seeing my TX and Rx load value and also people said by seeing 30 sec input and output rate of interface

                              (5 minute input rate 529000 bits/sec, 35 packets/sec

                                5 minute output rate 742000 bits/sec,40 packets/sec)

                              but i don't lnow how the calculate the values to know whether it is over utilizing or not.so i request u pls explain this concept to me m confuse becoz my BW is 256 Kb and input rate showing is 529000 bit/sec m not able to interpret with these values

                               

                              pls explain throughly

                              • 12. Re: Interface Bandwidth Utilization calculation method
                                Brian

                                The formula used to determine the utilization across any network connection is as follows:

                                 

                                Utilization (U) Percentage = (Throughput/Data Rate) x 100

                                 

                                Brian

                                 

                                • 13. Re: Interface Bandwidth Utilization calculation method
                                  Parveen

                                  Brian Sir

                                   

                                  Can have one example for above formula demonstartion of this forumla in real secanrio

                                  • 14. Re: Interface Bandwidth Utilization calculation method
                                    Brian

                                    So do you have a serial port in the router?   Do you have a rate limit on the Fastethernet port?  Just trying to understand, because based on the output of your "show interface f0/0" command you are far from being over utilized.

                                     

                                    It is very simple.  Look at the out of your "show interface f0/0" command.

                                     

                                    FastEthernet0/0 is up, line protocol is up

                                      Hardware is Gt96k FE, address is 001d.e60b.0a26 (bia 001d.

                                        Internet address is 192.168.8.1/24

                                      MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

                                         reliability 255/255, txload 1/255, rxload 1/255

                                      Encapsulation ARPA, loopback not set

                                      Keepalive set (10 sec)

                                      Full-duplex, 100Mb/s, 100BaseTX/FX

                                      ARP type: ARPA, ARP Timeout 04:00:00

                                      Last input 00:00:01, output 00:00:00, output hang never

                                      Last clearing of "show interface" counters 05:57:38

                                      Input queue: 0/75/0/0 (size/max/drops/flushes); Total outp

                                      Queueing strategy: fifo

                                      Output queue: 0/40 (size/max)

                                      5 minute input rate 529000 bits/sec, 35 packets/sec

                                      5 minute output rate 742000 bits/sec,40 packets/sec

                                         568283 packets input, 165463931 bytes

                                         Received 3970 broadcasts, 0 runts, 0 giants, 0 throttle

                                         0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

                                         0 watchdog

                                         0 input packets with dribble condition detected

                                         596783 packets output, 453850117 bytes, 0 underruns

                                         0 output errors, 0 collisions, 0 interface resets

                                         0 babbles, 0 late collision, 0 deferred

                                         0 lost carrier, 0 no carrier

                                         0 output buffer failures, 0 output buffers swapped out

                                     

                                    Do you see the values in RED?  When you see the following 225/255 or 240/255 etc then your load is going up.  A load of 255/255 is completely saturated.  Not good.  So, you want to see low numbers here.  The lower the better.  When these are high, then look at the numbers in BLUE.  Use the formula from my previous post and calculate the Utilization Percentage.

                                     

                                    Brian

                                     

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