[c-nsp] Network Analyser with n-way support

[Thomas Kernen]

>> Currently debugging an issue with autonegociation (n-way) between 2
>> network devices for which it appears that neither vendor can solve 
>> the issue directly. We are now trying to locate an analyser that will 
>> allow us to sniff the n-way negociation from both devices but without 
>> the ports on the analyser doing their own negociation with the end 
>> devices, so basically I'm looking for a "pass through" analyser.
>>
>> Unfortunally I'm unable to locate such a device that does provide not 
>> only the layer 2/3/+ but also the "pass through" feature for the 
>> ports. Suggestions or workarounds are welcomed.
>>
> You can plug most any analyzer into a "passive tap".  But I don't 
> think
> that's going to help you with this.  The N-way negotiation is encoded
> in fast link pulses, which are not any kind of frame that a NIC can
> receive and capture.  You'd need something like an oscilloscope to see
> the FLP.  Or register-level access to a NIC chipset.
>
> I thought that by now the number of chipsets/PHY available to all 
> vendors
> had greatly consolidated and that any interoperability problems are 
> well-known.
> Cisco even lists some of those in a troubleshooting article on CCO in
> http://www.cisco.com/warp/public/473/46.html.
> Can you find out the particular PHY used on each end?  For Cisco, the
> output of "show controller" will provide that.

Thanks for the input, actually we don't have acces to the chipset 
registers on either devices and the existing implementations don't allow 
us to probe the status of the port on these devices. If we insert a 
switch between the 2 devices it solves the issue but that's only a 
workaround, we have 600 ports with this issue.

The passive tap (that was the name I was looking for, couldn't remember, 
thx) is what we are looking into right now but as you mentioned vendors 
supporting hardware that does do the FLP analysis is very limited.

Thomas