[mrtg] If[In|Out]Octets seems to return bits intead of bytes

[Ionel GARDAIS]

Hi all,

I am using MRTG to graph traffic on a Foundry chassis.
Links act at 1Gb FD.

When I retrieve the ifInOctets and ifOutOctets of one port, graphed
traffic does not exceed 13MB/s.
I have to multiply the retrieved values by 8 to get a somewhat realistic
100MB/s.

My question is : ifInOctets and ifOutOctets should be bytes counters so
why do I need to multiply these values by 8 ?
(note : I tested the link with data transfert, it really act as a 1Gb
link, this is not a hardware misconfiguration)

Here is an example target :

Directory[tina]: net/tina
Title[tina]: tina network
PageTop[tina]: tina network</H1>
PNGTitle[tina]: Network Utilization
Target[tina]: ifInOctets.513&ifOutOctets.513:***@172.31.250.253 * 8
Options[tina]: growright,pngdate,nopercent
MaxBytes[tina]: 1342177280
WithPeak[tina]: ymw

Thanks,
Ionel
--
Ionel GARDAIS ~ ***@geomath.fr
Junior System-Network Administrator
Phone : [phone]
Fax : [phone]

[Eric Brander]

Post by Ionel GARDAIS
Hi all,
I am using MRTG to graph traffic on a Foundry chassis.
Links act at 1Gb FD.
When I retrieve the ifInOctets and ifOutOctets of one port, graphed
traffic does not exceed 13MB/s.
I have to multiply the retrieved values by 8 to get a somewhat realistic
100MB/s.

If you want it in bits/second, then just use the "bits" option. Its in
the reference.html.

HTH,

Eric Brander

[Pavel Ruzicka]

Post by Ionel GARDAIS
When I retrieve the ifInOctets and ifOutOctets of one port, graphed
traffic does not exceed 13MB/s.
I have to multiply the retrieved values by 8 to get a somewhat realistic
100MB/s.

You must read 64 bit counters ifhcinoctets and ifhcoutoctets.
Add :::::2 to your target. This enables SNMP version 2 and 64bit counters.
If you use cfgmaker, add option: --snmp-options=:::::2

Best regards,

Pavel Ruzicka

[Ionel GARDAIS]

Hi Pavel,

Working with SNMP v1 or v2c both return counter32 values :

[***@br40st11 ~]$ snmpget -c public -v 1 res0-foundry1 ifOutOctets.513
IF-MIB::ifOutOctets.513 = Counter32: 1398061606
[***@br40st11 ~]$ snmpget -c public -v 2c res0-foundry1 ifOutOctets.513
IF-MIB::ifOutOctets.513 = Counter32: 1398282706

Is this an MRTG internal cooking ?

Post by Pavel Ruzicka

Post by Ionel GARDAIS
When I retrieve the ifInOctets and ifOutOctets of one port, graphed
traffic does not exceed 13MB/s.
I have to multiply the retrieved values by 8 to get a somewhat realistic
100MB/s.

You must read 64 bit counters ifhcinoctets and ifhcoutoctets.
Add :::::2 to your target. This enables SNMP version 2 and 64bit counters.
If you use cfgmaker, add option: --snmp-options=:::::2
Best regards,
Pavel Ruzicka
--
Archive http://lists.ee.ethz.ch/mrtg
FAQ http://faq.mrtg.org Homepage http://www.mrtg.org
WebAdmin http://lists.ee.ethz.ch/lsg2.cgi

--
Ionel GARDAIS ~ ***@geomath.fr
Junior System-Network Administrator
Phone : [phone]
Fax : [phone]

[Eric Brander]

Post by Ionel GARDAIS
Hi Pavel,
IF-MIB::ifOutOctets.513 = Counter32: 1398061606
IF-MIB::ifOutOctets.513 = Counter32: 1398282706
Is this an MRTG internal cooking ?

Counter wrap.

In a 5-minute polling interval of a 32-bit counter you can rate up to
109 Mbps before the small counter wraps and MRTG will graph inaccurate data.
In a 1-minute polling interval of a 32-bit counter you can rate up to
546 Mbps before the wrap and blown graphs.

Without 64-bit counters you will not likely be able to accurately graph
a 1000 Mbps link unless that link never exceeds those numbers for the
specified interval.

Search the list for "counter wrap" and you will find dozens of threads
on this topic.

HTH,

Eric Brander

[Daniel J McDonald]

Post by Ionel GARDAIS
Hi Pavel,
IF-MIB::ifOutOctets.513 = Counter32: 1398061606
IF-MIB::ifOutOctets.513 = Counter32: 1398282706
Is this an MRTG internal cooking ?

Yes, when snmpv2 is attempted, mrtg probes to see if ifHCInOctets exists
and is reasonable. If so, the HC counters are polled instead of the v1
ifInOctets oid.
--
Daniel J McDonald, CCIE # 2495, CNX, CISSP # 78281
Austin Energy

***@austinenergy.com

[Ionel GARDAIS]

Hi Eric,

I don't want bits/sec, I'd like to have the graph scaled on my real link
bandwidth.
104 Mb/s is still the same than 13MB/s (and this is too low for a 1Gb link)

Ionel

Post by Eric Brander

Post by Ionel GARDAIS
Hi all,
I am using MRTG to graph traffic on a Foundry chassis.
Links act at 1Gb FD.
When I retrieve the ifInOctets and ifOutOctets of one port, graphed
traffic does not exceed 13MB/s.
I have to multiply the retrieved values by 8 to get a somewhat realistic
100MB/s.

If you want it in bits/second, then just use the "bits" option. Its in
the reference.html.
HTH,
Eric Brander
--
Archive http://lists.ee.ethz.ch/mrtg
FAQ http://faq.mrtg.org Homepage http://www.mrtg.org
WebAdmin http://lists.ee.ethz.ch/lsg2.cgi

--
Ionel GARDAIS ~ ***@geomath.fr
Junior System-Network Administrator
Phone : [phone]
Fax : [phone]