[nsp] Counting bps...

Volodymyr Yakovenko vovik at dumpty.org
Tue Mar 18 01:32:46 EST 2003

On Mon, Mar 17, 2003 at 02:20:04PM +0100, Iva Cabric wrote:
>Regarding bps statistics, there are several ways of collecting
>statistics (via SNMP):
>- standard In and Out Octets (32bits), which are usually used
> IF-MIB::ifInOctets.XXX
> IF-MIB::ifOutOctets.XXX

.iso.org.dod.internet.mgmt.mib-2.interfaces (.

>- same as above, but with extended range (64bits)
> IF-MIB::ifHCInOctets.XXX
> IF-MIB::ifHCOutOctets.XXX

.iso.org.dod.internet.mgmt.mib-2.ifMIB (.

This output could be confused, small correction - ifInOctets (SMIv1 ifTable)
and ifHCInOctets (SMIv2 ifXEntry) reside in different MIBs. However in net-snmp
they are grouped in one file (IF-MIB.txt).

>I suppose that smaller differences were caused by different time points
>when statistics are actually updated by router itself (I dont think that
>ifInOctets is updated for every byte or every packet and locIfInBitsSec
>is updated only on load-interval).

According to Cisco's documentation on conventional routing architectures
byte and packet counters are updated on per packet basis.

>Does anyone have other (or more) experience with bps statistics gathering
>and would like to share information about it and ways of doing it?

One practical suggestion - _always_ do tests of new IOSes for possible SNMP 
counter's bugs. 


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