From: subodh.rawat@wipro.com
Date: Tue Feb 10 2009 - 14:17:23 ARST
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
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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
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