[mrtg] MRTG and Gigabit and 10GB
Daniel J McDonald
dan.mcdonald at austinenergy.com
Thu Nov 8 14:09:09 CET 2007
On Thu, 2007-11-08 at 09:39 +0000, John Cushnie wrote:
> Also where do the Max speeds reported for the interface come from?
I just re-read the source code. If you are using snmp version 2 or 3,
then ifHighSpeed is consulted if ifSpeed is zero, undefined, or 2**32 -
1. If you are using snmp version 1, then ifSpeed is used without any
However, it would be theoretically possible to use snmp version 1, even
with a 10G interface, if Interval: were set low enough. However, I
think you need an interval of .8 seconds. But it would be possible to
have an interface with a speed greater than 4Gb/s (maybe some sort of
GigEtherChannel) that could polled with snmp v1.
I think a better patch would be to:
1. Always check ifHighSpeed, even if snmpv1 is used.
2. Warn if the maximum speed exceeds the limits of 32 bit counters for
the interval selected.
> 1GB is reporting 125.0 MB/sec
> 10GB is reporting 536.9MB/sec
Daniel J McDonald, CCIE #2495, CISSP #78281, CNX
More information about the mrtg