06-21-2009 05:32 AM - edited 03-06-2019 06:22 AM
Hi,
I am seeing a strange problem with bandwidth usage reports.mrtg for one of the links shows different readings for input & output interfaces.
For eg. if inside interface graph shows 4 Mbps usage, outside interface for same duration shows much less than that.
Strangely this occurs only at certain times.Otherwise it seems fine.
I cross checked this with another tool which shows near correct usage.
Please advice.
Thanks.
06-21-2009 11:36 AM
Hello Sunny,
32 bit wide MIB interface counters can be affected by wrapping:
the graph points are calculated using the difference of last and penultimate reading.
But the octets variable can fill the 32 bits integer because it acts as an accumulator, and so sometimes the new value is actually smaller then the penultimate value.
Hope to help
Giuseppe
06-22-2009 06:22 AM
Thanks Giuseppe.
Any ways to overcome this & any specific links to learn more about it.
Appreciate your help!
06-22-2009 07:17 AM
Hello Sunny,
some platforms support 64 bit counters that have an HC in the name
ifinoctets = 32 bit counter
ifHCinoctets = 64 bit counter
Object ifHCInOctets
OID 1.3.6.1.2.1.31.1.1.1.6
Type Counter64
Permission read-only
see
http://tools.cisco.com/Support/SNMP/do/BrowseOID.do?local=en
Hope to help
Giuseppe
06-28-2009 06:34 AM
Thanks Giuseppe,my interface is fastethernet and router is 2811.
Does it support 32 or 64bit counters & how can we derive what interface supports how much bits?
By the docu you provided it seems to be affect of wrapping, but then am puzzled at how another monitoring tool gave pretty accurate reading for same time.
Appreciate your help.
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