Fibre Channel (SAN)

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dd
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Posts: 1
Registered: ‎07-25-2011

Brocade Fiberchannel Interface Monitoring Problem

Hi,

We're actually monitoring utilization of Brocade Fiberchannel (Brocade 4100) interface trought the SW-MIB file.

We  use this OID (1.3.6.1.4.1.1588.2.1.1.1.6.2.1.11 &  1.3.6.1.4.1.1588.2.1.1.1.6.2.1.12) who report the 'word' passing  throught the interface (.11 is TX and .12 is RX)

Refer to the OID description in the MIB file, this 'word' unit seems to be equal to 4 bytes (so 32 bit).

So is the formula : ('word value' * 32) / (1024*1024)   we should get the instant throughput in Mbit/s ???

But actually we offen report value out of the bandwith of the link.

Example:

the interface bandwith is 2 Gbit/s FD

@ Tuesday, June 28, 2011 11:00:00 AM, the word value is = 190800930

apply formula : (190800930 * 32) / (1024*1024) = 5822,78228759765 (so 5,822 Gbit/s ???)

Anyone got an idea or got this issue before ?

This is for an audit report and so it's a bit hurrry bor us.

Thanks all !

Regular Contributor
Posts: 178
Registered: ‎04-21-2008

Re: Brocade Fiberchannel Interface Monitoring Problem

Hi -

@ Tuesday, June 28, 2011 11:00:00 AM, the word value is = 190800930

190800930 is the number of words transmitted/received since last reset of counter, it's not a speed value !

To have speed you have to poll values at least twice and make difference : counter(T2) - counter(T1)/(T2 -T1) will give average speed between T1 and T2 timestamps.

I suggest you to use 64 bits SNMP counters available in FA-MIB (you won't have words but octets, easier to use)

connUnitPortStatCountTxElements 1.3.6.1.3.94.4.5.1.6

The number of octets or bytes that have been transmitted by this port. There is an one-second

periodic polling of the port. This value is saved and compared with the next polled value to compute

net throughput.

For Fibre Channel, ordered sets are not included in the count.

connUnitPortStatCountRxElements 1.3.6.1.3.94.4.5.1.7

The number of octets or bytes that have been received by this port. There is an one-second periodic

polling of the port. This value is saved and compared with the next polled value to compute net

throughput.

For Fibre Channel, ordered sets are not included in the count.

Hope this helps

Kind regards,

--

david

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