[mpls-linux-general] Better to use nfmark vs tc_index?

[James R. L. <jl...@mi...>]

After looking at iptable a bit more I see that it can set a nfmark via
the MARK rule.  Should I use this as oppsed to tc_index to influence the
LSP and EXP? (note that DSCP will still be an options)

I think I now understand what Olivier did, he created something similar
to MARK but for MPLS.  If we are going to continue to use that I would
like to change it alittle.  Instead of storing the mpls_index, I think it
should build a dst and store it with the rule.  This dst will direct the
skb to mpls_output() and will have the outgoung label info attached.
When it gets to mpls_output() MPLS processing will occur like normal.
The dst will be slapped on to any packet that matches the rule.

Do you think that by using nfmark we can accomplish the same thing?
We would have to relay upon another mean of getting data to mpls_output()
like a MPLS tunnel interface or a entry in the FIB that has been marked
for MPLS.  Once it gets to mpls_output() the nfmark could be used to influence
the LSP or EXP.

Ofcourse maybe it's just safer to have both options availble :-)

Now to the matter of tc_index.  It seems that nfmark can be used by a
scheduling classifier, but it looks like the classifier for tc_index is
better.  So it might be that nfmark (or a MPLS mark) is used to influence
LSP and EXP descisions (note that DSCP will still be option) and that
tc_index is used to influence scheduling.

Does that make any sense?  It's late.  I'm going to sleep and think about
it some more.

Jim
-- 
James R. Leu
jl...@mi...