Re: [NV-L] Incorrect bandwidth data above 100MB
2010-09-09 10:18:35
The proper formula for interface utilization
has always been, in fifth-grade aritmetic:
octets second
8bits 1
------ * ---------
* ----- * ----
second speed in bits
1octet 100
That is, ((ifInOctets / ifSpeed) *
8)/ 100
Expressed in reverse Polish in mibExpr.conf,
that should be
.1.3.6.1.2.1.2.2.1.10.
\
.1.3.6.1.2.1.2.2.1.5.
/ \
8 * 100
/
That's what it used to be. The last
mibExpr.conf that I have in my archives shows it a little different, but
the difference would express the % as a whole number (25%) rather than
as .25.
BandwidthUtilIn \
"8*100* ifInOctets / ifSpeed"
\
.1.3.6.1.2.1.2.2.1.10.
\
.1.3.6.1.2.1.2.2.1.5.
/ \
800 *
The high speed interfaces need to be
polled with SNMPv2 to get the 64bit mib values, and even then they are
likely to wrap if you don't poll frequently enough.
I wonder if the devices were discovered
using SNMPv1 community strings and are therefore being polled using 32-bit
variables?
I've been out of this for a while, so
I may be completely wrong.
Cordially,
Leslie A. Clark
IT Services Specialist, Network Mgmt
Information Technology Services Americas
IBM Global Services
(248) 552-4968 Voicemail, Fax, Pager
From:
| John M Gatrell <John.Gatrell AT uk.ibm DOT com>
|
To:
| Tivoli NetView Discussions <nv-l AT lists.ca.ibm DOT com>
|
Date:
| 09/09/2010 05:23 AM
|
Subject:
| Re: [NV-L] Incorrect bandwidth data
above 100MB
|
Sent by:
| nv-l-bounces AT lists.ca.ibm DOT com |
Yes, I'm seeing something similar. I'm running on AIX NetView 715 Fixpack3.
The graphs did not look right for me when I started monitoring a router
with a Gigabit interface and a Bandwidth 200000 (200 Mbit)
statement. The previous router, which had a bandwidth 100000 statement,
was graphed correctly.
I'm using an entry in mibExpr.conf namely
BandwidthUtilOut \
"8*100* ifOutOctets / ifSpeed" \
.1.3.6.1.2.1.2.2.1.16. \
.1.3.6.1.2.1.2.2.1.5. / \
800 *
I tried dividing the ifSpeed by 800 first and this gave more believable
results.
Your mileage may vary. I tried using:
NewUtilOut \
"ifOutOctets/(ifSpeed/800)" \
.1.3.6.1.2.1.2.2.1.16. \
.1.3.6.1.2.1.2.2.1.5. \
800 / /
John Gatrell
Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number
741598.
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6
3AU
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