[c-nsp] Wierd MPLS/VPLS issue

[adamv0025 at netconsultings.com]

> Simon Lockhart
> Sent: Friday, December 02, 2016 11:44 AM
> To: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] Wierd MPLS/VPLS issue
> 
> On Wed Nov 23, 2016 at 12:01:20PM +0000, Simon Lockhart wrote:
> > On Fri Nov 04, 2016 at 03:40:05PM +0000, Simon Lockhart wrote:
> > > To me, everything *looks* right, it's just that some VPLS traffic
> > > traversing the new link gets lost.
> >
> > For those who are interested...
> >
> > Well, I finally got to the bottom of this, and have pushed it to Cisco
> > TAC for a fix...
> 
> Cisco TAC finally accepted the issue. Bug CSCvc33783 has been logged.
Nexus
> BU has investigated.
> 
> Response is...
> 
> "[...] unfortunately this is an ASIC limitation on the Nexus 9000 switches
and
> is therefore not fixable."
> 
I'd like to understand some details about why it is actually happening.  
I mean I'd understand when the switch is being proactive and tries to
load-balance on contents of the packet and might parse headers incorrectly
messing up hashing and causing out of order packets. 
But dropping the frame because of that, what the heck? 

Can the SW be instructed what headers to use during hashing in order to
avoid this issue? 


adam

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