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

[Marty Adkins]

Thomas Kernen wrote:
> 
> 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.

- Marty