The MPLS WG Archive

[Loa Andersson <loa.andersson@utfors.se>]

All,

promissed not to add to the noise un-necessarily, but since this is
one of those wonderfully unstructured threads where you can say 
anything and get flogged whether it is sensible or not.

I can't resist:

There seems to be at least four different views voiced on this 
thread.

1. "MPLS is níce and dandy, nothing needs to be done, just because it
   is not an ATN replcement"
2. "MPLS is níce and dandy, nothing needs to be done, just because it
   is not an ATN replcement"
3. MPLS is not nice and dandy, because it is ATM all over again.
4. MPLS is nice and dny, but there is a need to review what we ccome up
   with so far, we don't want to make the same misstakes all over again.

Understanding that there are an enormous potential make this far more 
granular, but won't just now.

I think that while recognizing that MPLS is useful and simple at the
core,
there is still a need to go back and asked ourselves if everything that 
has been added is needed.

/Loa


Eric Osborne wrote:
> 
> On Mon, Aug 27, 2001 at 03:30:33AM -0700, Sham Chakravorty wrote:
> > See comments inline -
> >
> 
> I'm probably just fanning the flames of a religious war, but what the
> hell...
> 
> > > I'll try to be even more to the point - the first and foremost requirement
> > > is simplicity. If MPLS is not simple, there will be no MPLS!
> >
> > In IMHO, MPLS is not simple.  Consider all the drafts that have been
> > fielded for the past four years - over 120 (?) or so to solve its
> > many issues - not withstanding mixed VC setup criteria of RSVP-TE
> > and CR-LDP for a starter.
> 
> Sure, but consider also the number of large MPLS deployments.  One
> would never add an additional control plane or two to a network if
> there were no benefit to be gained from it; it seems obvious that at
> least some people have decided the potential benefits of MPLS are
> worth whatever hassle it brings.
> 
> > MPLS unfortunately does not meet the simplicity criterion. (You may have
> > prophesized something here in line with what is coming out in the press more
> > and more.  See Lightreading.com's recent article: "Poll: Is MPLS BS?"
> > Majority taking the poll seem have to said, yes. One would have been hung in
> > the broad day light to put out an article with such a title just a year
> > ago.)
> 
> Can you enumerate these 'simplicity criterion'?  And as you do so, try
> to come up with rules that demonstrate that MPLS is not simple but
> BGP, OSPF, IS-IS, IP, ATM, and/or SONET are.
> 
> And not that I want to start trashing prestigious on-line industry
> trade rags, but lightreading strikes me as the Daily Star of the
> Internet news industry.  But I suppose I'm biased; I work for Big
> Brother...:)
> 
> >
> > > The second requirement is usefulness, if MPLS is not useful, there will be
> > > no MPLS (even though it is simple).
> >
> > With no built-in framework for QoS deployment and no extensibility to
> > enterprise networks (over Ethernets, e.g.), its usefulness as many have
> > pointed out before, on this board and elsewhere, is at best very limited.
> 
> I guess I don't understand the point about QoS.  Pretty much every
> vendor I've ever dealt with treats the EXP bits as Precedence bits.
> So there's no inherent *additional* QoS framework in MPLS, but it can
> certainly be deployed in much the same way as IP QoS can.  And I
> suspect that if MPLS had a built-in QoS framework, then the pundits
> would use this to claim that MPLS was not simple.  However, ongoing
> work (DS-TE and L-LSP) will give more granular control over QoS than
> IP has, albeit at a price of complication.
> 
> As far as extensibility to enterprise networks, are you talking about
> the various forms of L2 over MPLS?  It seems to me that these things
> very much exist; we are shipping two different transport types, and at
> least 3 other vendors that I know of have some flavor of L2 over
> MPLS.  And depending on how you define extensability, there's always
> 2547 and its ability to merge with the enterprise IGP at a L3 level.
> 
> 'simple' != 'effortless'.  Nothing in networking is effortless.  A
> better way to look at it, IMHO, is whether the tradeoff in deploying
> MPLS to do whatever services you want (L2 transport, L3 VPNs, TE,
> BGP-free core, whatever) is worth the work of an extra few control
> planes, a new set of operational things to learn, and so forth.  if
> it's worth it, use MPLS; if it's not, don't.
> 
> eric

-- 
Loa Andersson
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