From: paul cosgrove (paul.cosgrove@gmail.com)
Date: Wed Feb 11 2009 - 08:04:55 ARST
You are probably exporting sampled data, for instance every 1:100 packets
and so the throughput figures are approximations. If your routers export
1:100, but your monitoring server has been told that a different sampling
rate is being used, then your figures may be very inaccurate.
On Tue, Feb 10, 2009 at 4:17 PM, <subodh.rawat@wipro.com> wrote:
> Guys,
>
>
>
> Issue is that I am using Adventnet Netflow analyzer (Demo Professional
> Version). The speed graph has shown at time beyond 1Gbps speed (like
> 1.5Gbps, 2Gbps 2.2Gbps, 2.5 Gbps etc).
>
>
>
> I am confused if my link is only 1Gbps (even the hardware is Gigabit port),
> then how come Netflow Analyzer showing different result at time.
>
>
>
> Is it a bug in Adventnet OR their speed calculation method is different OR
> this is something related to Cisco Netflow?
>
>
>
> Please can someone answer this if you have faced this kind of issue?
>
>
>
> Many Thanks
>
> Subodh
>
>
> ------------------------------
>
> *From:* paul cosgrove [mailto:paul.cosgrove@gmail.com]
> *Sent:* Tuesday, February 10, 2009 4:10 PM
> *To:* James MacDonald
> *Cc:* Subodh Singh Rawat (WT01 - ENERGY & UTILITIES); <
> ccielab@groupstudy.com>
> *Subject:* Re: throughput query on 1Gbps link
>
>
>
> If you wish to be compliant with 802.3 then a transmitting device should
> not use an interframe gap smaller than the time it takes to send 96 bits.
> However there are cases where you may wish to do so. Intel used to use this
> on some of their EtherExpress NICs to allow for faster throughput (see
> http://en.wikipedia.org/wiki/Interframe_gap) and it is also used for
> RFC2889 compliance testing when deliberately overloading devices:-*
> 5.6 Forward Pressure and Maximum Forwarding Rate
> *....
>
> *5.6.3.2** Minimum Interframe Gap*
>
> .....
>
> Test frames *SHOULD* be transmitted to the first port (port 1) of the
> DUT/SUT with an interframe gap of 88 bits. This will apply forward pressure
> to the DUT/SUT and overload it at a rate of one byte per frame. The test
> frames *MUST* be constructed with a source address of port 1 and a
> destination address of port 2.
>
> The FR on the second port (port 2) of the DUT/SUT is measured. The measured
> Forwarding Rate should not exceed the medium's maximum theoretical
> utilization (MOL).
>
> A reduced interframe gap would not make any difference to passive DWDM
> equipment, it just sees a wavelength and passes it through.
>
> Paul.
>
>
> On Tue, Feb 10, 2009 at 1:45 PM, James MacDonald <j4m3sm63@yahoo.ca>
> wrote:
>
> I think maybe the app was calculating other test data as well either by
> config error or bug. Maybe send and recieve were combined somehow ... If you
> have a physical GigE port then you can only ever get 1Gbps bi-directional.
>
>
> James MacDonald
> E: jamesm@nevolutions.ca
> P: 416-580-6873
>
> The world is evolving ... is your network?
> Email info@nevolutions.ca to see how we can transform your network!
>
> On 9-Feb-09, at 10:47 AM, <subodh.rawat@wipro.com> wrote:
>
> Hi folks,
>
>
>
> Can you please let me know if a 1Gbps DWDM link can send data at more
> speed than 1Gbps?
>
>
>
> Thanks
>
> Subodh
>
>
>
>
>
>
> * Please do not print this email unless it is absolutely necessary. *
>
> The information contained in this electronic message and any attachments to
> this message are intended for the exclusive use of the addressee(s) and may
> contain proprietary, confidential or privileged information. If you are not
> the intended recipient, you should not disseminate, distribute or copy this
> e-mail. Please notify the sender immediately and destroy all copies of this
> message and any attachments.
>
> WARNING: Computer viruses can be transmitted via email. The recipient
> should check this email and any attachments for the presence of viruses. The
> company accepts no liability for any damage caused by any virus transmitted
> by this email.
>
> www.wipro.com
Blogs and organic groups at http://www.ccie.net
This archive was generated by hypermail 2.1.4 : Sun Mar 01 2009 - 09:44:10 ARST