On Fri, May 25, 2012 at 01:24:00AM +0200, ravi.ke...@telekom.com wrote:
> On Thu, May 24, 2012 at 11:58:53PM +0200, ravi.ke...@telekom.com wrote:
> > Ben Pfaff writes:
> > > get_l3_ttl_and_tos()
> > > --------------------
> > > 
> > > Why does get_l3_ttl_and_tos() consider an unknown IP version as 
> > > success, with a default?  This seems odd.
> > 
> > To handle non-IP traffic i.e push/pop MPLS over non-IP traffic e.g. 
> > ARP(practical?), VPLS. I had also mentioned in previous discussion 
> > that MPLS ttl actions will not work for these type of traffic but 
> > other actions lke push_mpls,pop_mpls, set_mpls_label/set_mpls_tc would 
> > be. In this function I keep them to default for non-IP traffic.
> 
> But that only comes up in one situation: copying the TTL inward or outward 
> when there is exactly one MPLS label.  In other situations (pushing an MPLS 
> label or popping one) we know the correct inner Ethertype either because it's 
> in the packet or because it's an argument to the action.  When we know it, we 
> should use it. 
> 
> <rk> Cases for multiple MPLS headers currently happen only at Provider core 
> routers and yes in that case we don't have to worry, I was thinking more in 
> terms of Provider-Edge or MPLS termination point.  For those multiple MPLS 
> label case it is already handled and I use existing mpls header to copy.  I 
> will closely look at it one more time probably I am missing your point. I 
> think you are probably saying extract ethtype from packet and use it to 
> derive ttl and tos?

Yes, that's what I had in mind.

Thanks,

Ben.
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