show amount of traffic passing throw interface
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Posted by juanbabi@gmail.com on October 18, 2007, 10:41 am
Please log in for more thread options what is the IOS command to view how much traffic is passing in/out an interface in a cisco switch/router? I need it in kbps it there such a command? thanks a lot ! Juan | |||||||||||||
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Posted by Trendkill on October 18, 2007, 11:35 am
Please log in for more thread options Show int <interface> (example: show int f0/1).
You are looking for txload and rxload (transmit and receive), and it will be in a number from 0 to 255. You then use that to calculate your bandwidth. As an example, if its a 100 meg ethernet interface, 126/255 would be 50 megabits. If it was a 45 meg DS3, 200/255 would be about 35.3 meg. Only other way to do it easier is to get an snmp poller to get it off the router via snmp, but it still uses the same function and just does the math for you. | |||||||||||||
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Posted by Sam Wilson on October 18, 2007, 11:54 am
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> > Hi,
> > > > what is the IOS command to view how much traffic is passing in/out an > > interface in a cisco switch/router? > > > > I need it in kbps > > > > it there such a command? > > > > thanks a lot ! > > > > Juan >
> Show int <interface> (example: show int f0/1). > > You are looking for txload and rxload (transmit and receive), and it > will be in a number from 0 to 255. You then use that to calculate > your bandwidth. As an example, if its a 100 meg ethernet interface, > 126/255 would be 50 megabits. If it was a 45 meg DS3, 200/255 would > be about 35.3 meg. Only other way to do it easier is to get an snmp > poller to get it off the router via snmp, but it still uses the same > function and just does the math for you. Or, if your traffic is fairly stable, just take the 5 minute input and output rates given by "show int ..." - these are exponentially weighted moving averages of the traffic levels so they only approximate to the traffic level at any particular time. You can also read the input and output packet and byte counts at set times and subtract them (like an SNMP poller would). Beware that on some models the interface counts are only updated at intervals (10 sec on the 6500 I've just tried it on) so either read them frequently and look for the points at which they change, or read them infrequently so the update period doesn't matter. Sam | |||||||||||||
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Posted by on October 18, 2007, 12:24 pm
Please log in for more thread options >> Hi,
>> >> what is the IOS command to view how much traffic is passing in/out an >> interface in a cisco switch/router? >> >> I need it in kbps >> >> it there such a command? >> >> thanks a lot ! >> >> Juan >
> Show int <interface> (example: show int f0/1). > > You are looking for txload and rxload (transmit and receive), and it > will be in a number from 0 to 255. You then use that to calculate > your bandwidth. As an example, if its a 100 meg ethernet interface, > 126/255 would be 50 megabits. If it was a 45 meg DS3, 200/255 would > be about 35.3 meg. Only other way to do it easier is to get an snmp > poller to get it off the router via snmp, but it still uses the same > function and just does the math for you. Interesting. That approach seems somewhat backward to me. If you look further on the show interface display you'll see "5 minute input rate" and "5 minute output rate". My testing indicates that the "5 minute input rate" and "5 minute output rate" are used as the basis for computing txload and rxload. txload = floor ( 255 * 5 minute input rate / interface bandwidth ) rxload = floor ( 255 * 5 minute output rate / interface bandwidth ) | |||||||||||||
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Posted by alexd on October 18, 2007, 2:31 pm
Please log in for more thread options Trendkill wrote:
> On Oct 18, 12:24 pm, bri...@encompasserve.org wrote:
>> Interesting. That approach seems somewhat backward to me.
>> >> If you look further on the show interface display you'll see >> >> "5 minute input rate" and "5 minute output rate". >> >> My testing indicates that the "5 minute input rate" and "5 minute >> output rate" are used as the basis for computing txload and rxload. >> >> txload = floor ( 255 * 5 minute input rate / interface bandwidth ) >> rxload = floor ( 255 * 5 minute output rate / interface bandwidth ) >
> According to Cisco: "Load on the interface (in the transmit "tx" and > receive "rx" directions) as a fraction of 255 (255/255 is completely > saturated), calculated as an exponential average over 5 minutes." > > However, I need to understand what 'exponential average' means. Just as a guess, I would imagine it means that more recent values [within the five minute window] have an exponentially greater weighting when calculating the average. So whilst it's an average over five minutes, it reacts quicker to changes in network usage than an unweighted one. -- <http://ale.cx/> (AIM:troffasky) (UnSoEsNpEaTm@ale.cx)
19:29:19 up 17 days, 21:18, 3 users, load average: 0.12, 0.15, 0.17
09 f9 11 02 9d 74 e3 5b d8 41 56 c5 63 56 88 c0 | |||||||||||||
>
> what is the IOS command to view how much traffic is passing in/out an
> interface in a cisco switch/router?
>
> I need it in kbps
>
> it there such a command?
>
> thanks a lot !
>
> Juan