Subject: RE: (ION) Optical routing

From: Fred Baker <[email-masked]>
Date: Mon, 18 Sep 2000 16:49:10 -0700

At 07:15 PM 9/18/00 -0400, Peter Tam wrote:
>How would it be different from the proposed work in the IP over Optics BOF 
>charter?

isn't that tied rather closely to MPLS, as in "the whole world is MPLS and 
who needs IP anyway?" One wonders whether it might be worthwhile to discuss 
*IP* over Optics somwhere.

X-Info: To unsubscribe, email [email-masked]' with
X-Info: 'unsubscribe ion' in the body of the message.

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From: "Andrew G. Malis" <[email-masked]>
Date: Mon, 18 Sep 2000 21:46:31 -0400

Fred, Peter, et al,

*IP* over Optics, as Fred put it, is the point of the proposed ipo 
WG.  There are enough optical-specific problems that still need to be 
solved that forming a new WG makes sense, and the old ion group would have 
to be rechartered anyway if we wanted to restart it.

If we continue this conversation, I would like to ask that we move it to 
the [email-masked] list so that the people there can 
participate (not to mention that a good portion of the email addresses on 
the ion list are now dead).  Go to 
http://lists.bell-labs.com/mailman/listinfo/ip-optical to join the list or 
read the archives.  The presentations from the July ipo meeting can be 
found at http://wwwext.eng.us.uu.net/ipo/presentations/ietf_48/.

Thanks,
Andy

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At 9/18/2000 04:49 PM -0700, Fred Baker wrote:
>>How would it be different from the proposed work in the IP over Optics 
>>BOF charter?
>
>who needs IP anyway?" One wonders whether it might be worthwhile to 
>discuss *IP* over Optics somwhere.

________________________________________________________________________
Andrew G. Malis     [email-masked]     phone:408-383-7223
Vivace Networks/2730 Orchard Parkway/San Jose, CA 95134/fax:408-904-4748
http://www.vivacenetworks.com

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From: Yakov Rekhter <[email-masked]>
Date: Thu, 21 Sep 2000 13:22:11 -0700

Fred,

> who needs IP anyway?" 

This is an interesting perspective on MPLS. Is that your own ?

Yakov.

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From: Fred Baker <[email-masked]>
Date: Sat, 23 Sep 2000 20:50:02 +0200

>This is an interesting perspective on MPLS. Is that your own ?

Sorry for the delay in responding; I have been in transit.

It was the comment, roughly verbatim, of a person who attended the last 
IETF to attend the BOF, whom I met in the airport. Thankfully, I collected 
neither his name nor that of his company. I was, er, sputter, ...

My perspective on MPLS is that it is a facility that has certain potential 
utilities, such as in BGP/MPLS VPNs and in Traffic Engineering. It is 
essentially a circuit switching architecture, and is therefore not 
connectionless. I rather believe that Len Kleinrock was onto something in 
his paper on the subject in 1964, and so get a little twitchy at the thought.

I don't see the need for MPLS in the optical layer (unless you view the 
lambda frequency itself as the label), and it may get in the way of some 
interesting things; I'd rather not restrict things at this point if I don't 
have to. A lambda encodes a class of traffic. It may be "the traffic going 
to this next hop", "the traffic of this class going to this next hop", "the 
traffic of this class going to this set of next hops", or a list of other 
possibilities. In that latter case, I could imagine the set of next hops 
being linearly related along a fiber path (ie, several successive systems 
down one fiber path who each see the same light beam and each extract a 
subset of its contents), or the set being a POP (so that the next hop is 
the entry to the POP, and the data is then distributed among systems at the 
POP). The light beam is itself a "circuit" in some sense, and having 
additional circuits within it doesn't make a lot of sense. I would prefer 
to see IP datagrams inside the light beam, not bundled circuits.

Call it a preference or a religious opinion, if you need to categorize 
opinions. I would rather do my work at the IP layer.

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From: Yakov Rekhter <[email-masked]>
Date: Mon, 25 Sep 2000 06:18:07 -0700

Fred,

> utilities, such as in BGP/MPLS VPNs and in Traffic Engineering. 

These are certainly some of the applications of MPLS.

> It is essentially a circuit switching architecture, and is therefore not 
> connectionless. 

That statement shows that you have a rather limited understanding of
MPLS, as while MPLS can be used to provide circuit switching
architecture, it also could be used to provide a pure connectionless
architecture as well.

> I rather believe that Len Kleinrock was onto something in 
> lambda frequency itself as the label), 
 
From the semantical point of view lambda is a label (please read read
draft-awduche-mpls-te-optical-02.txt for more details on this).  Having
said this, I understand that some folks, due to their irrational
attitude towards MPLS, may claim that MPLS has nothing to do with the
optical layer. And no amount of rational arguments is going to change
this.

> and it may get in the way of some 
> possibilities. 

Thanks for describing how traffic could be mapped into MPLS FECs.

> In that latter case, I could imagine the set of next hops 

Your preference is clear. And since it is based on a religious opinion
(as you acknowledged yourself), I see no reason to continue a rational 
discussion on this topic.

Yakov.

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From: Fred Baker <[email-masked]>
Date: Mon, 25 Sep 2000 16:24:30 +0200

At 06:18 AM 9/25/00 -0700, Yakov Rekhter wrote:
>I see no reason to continue a rational

to each his own. I thought the rest of use were having a reasonably 
rational discussion. If you don't mind, we might continue.

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From: Grenville Armitage <[email-masked]>
Date: Tue, 26 Sep 2000 00:59:52 -0700

Fred,

	[..]
 > The light beam is itself a "circuit" in some sense, and having

Insofar as we are used to channelized SONET interfaces, which are
essentially circuits within circuits, why does it not make sense for
lamda paths to carry L(abel)SPs?  Think of it as channelization.

As for using MPLS control protocols to establish and maintain
lamda paths - consider it an operational simplification for
certain SPs. If I own all my fibre, and my business is IP, then
it might be nice to train my operations people on just one set of
peculiar routing protocols and failure modes. (Naturally, if my
business is simply optical circuits, resold to overlay customers,
non-MPLS alternatives may be equally appealing.... although this
still leaves open the possibility of using MPLS protocols as UNI
protocols for the optical cloud, but now we're going way afield...)

cheers,
gja
________________________________________________________________________
Grenville Armitage                    http://members.home.net/garmitage/
Bell Labs Research Silicon Valley