[f-nsp] Testing traffic forwarding issues on FESX448-PREM

[ebradsha at gmail.com]

I'm working on testing several FESX448-PREM switches.

One of the switches in my test group is known to be bad. It was previously
installed as a top of cabinet switch, 42 servers were connected to it, all
port lights came on, full duplex, no errors, low CPU, etc but ports 13-24
would not forward traffic. As I understand it, this is due to a bad ASIC
that covers port region 13-24.

However, I now have this bad switch at my work bench and I cannot replicate
the same forwarding issue with port region 13-24.

At my work bench, I have port 1 as the uplink and I've been connecting my
laptop to ports 2-48 sequentially using a CAT6 cable while running a
continuous ping to a public IP. Interestingly, all the ports now work fine
-- port region 13-24 no longer has forwarding issues.

Does anyone know how this is possible? If there's a bad ASIC for port
region 13-24, then I'd expect this problem to occur 100% of the time.

I tried a couple other things afterwards. I had the theory that I needed
more ports active at once in order to trigger the forwarding issue. So I
first took a layer 2 switch and connected it on a bunch of ports with the
FESX448. CPU usage immediately went to 100% on the FESX448. I figured
something recursive routing was happening with the layer 2 switch. Next, I
put the layer 2 switch into boot monitor mode so it wouldn't do any
routing. That resolved the 100% CPU issue, but again I'm still unable to
replicate the traffic forwarding issues with ports 13-24.

Any suggestions on how I can replicate the forwarding issue and effectively
test the remaining switches would be much appreciated!
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