Subject: Re: Proposed way to move forward re ATM/MPLS

From: Robert Raszuk <[email-masked]>
Date: Mon, 06 May 2002 21:55:55 +0200

Jim,

Now I can't resist :) ...

Your argument actually is pro Luca's proposal not against it. Why ...
simply because it is very difficult to run TDM over IP/MPLS like network
so if voip get's converted to TDP it better run on traditional ATM
switches not it's emulation over IP/MPLS transport. 

Giving impression by complicating the L2 transport protocols that they
will fix all QoS issues and that TDM like services over IP/MPLS are
going to be easy to provision without very good hardware shapers and
quite well engineered qos in the netowrk may IMHO generate more harm
then benefit for the potential users. In other words ATM data transport
over IP (AAL5) is all fine, but getting into transparent cell transport
then TDM over IP is getting on it's edge or even under the most of
today's IP network's capabilities.

R.

> Jim Harford wrote:
> 
> OK, I can't resist any longer ...
> 
> I hope at some point, Luca's VoIP gets converted to voice over TDM.  This
> is a requirement if he wants to call me or some other 800 million phone
> numbers worldwide.
> 
> In terms of revenue, it's a voice world, NOT IP.
> 
> Jim Harford
> 
> At 02:07 PM 5/6/2002 -0400, Rutemiller, John wrote:
> 
> > > -----Original Message-----
> > > From: Luca Martini [mailto:[email-masked]]
> > > Sent: Friday, May 03, 2002 2:27 PM
> > > To: Rutemiller, John
> > > Cc: [email-masked]
> > > Subject: Re: [PWE3] Proposed way to move forward re ATM/MPLS
> > >
> > >
> > >
> > >
> > > Rutemiller, John wrote:
> > >
> > > >>
> > > >>no, they probably won't listen to the ATM forum. After all
> > > >>ATM is a legacy protocol.
> > > >>This is an IP world.
> > > >>
> > > >>
> > > >
> > > >
> > > > I thought IP was the legacy protocol. At least that's what everyone
> > > > was saying when ATM was being developed. ;)
> > > >
> > > > There might be a lot of IP out there, but voice and leased
> > > line still pay the bills.
> > > >
> > > > John
> > >
> > >
> > > Yes, and all our voice runs over IP. :-)
> > >
> > > Luca
> > >
> >
> >
> >And how do you provide the QoS for the Voice IP? Do you over provision
> >the bandwidth, since there is so much of it available? Do you use MPLS
> >to provide traffic seperation and prority, along with over provioning?
> >Or, do you use ATM underneath the IP network to provide the proper QoS
> >separation between the voice traffic and the data traffic? Or maybe a
> >combination of these techniques.
> >
> >
> >John
> >
> >_______________________________________________
> >pwe3 mailing list
> >[email-masked]
> >https://www1.ietf.org/mailman/listinfo/pwe3
> 
> _______________________________________________
> pwe3 mailing list
> [email-masked]
> https://www1.ietf.org/mailman/listinfo/pwe3

---

From: Jim Harford <[email-masked]>
Date: Mon, 06 May 2002 16:30:26 -0400

Robert,
The original comment that started this sub-thread was
     "No, they probably won't listen to the ATM forum. After all ATM is a 
legacy protocol.  This is an IP world."

I take exception to that statement because it ignores the economic reality 
that carriers receive more of their revenue from voice and leased line 
services, not data services.

A large number of carriers have employed ATM to implement a network that 
delivers multiple services.  Some of the participants on this list are in 
the business of providing data services, and they believe that an ATM-MPLS 
network interworking solution should be optimized towards providing data 
services, where the data is presumed to be IP.  In contrast, the carriers 
using ATM to provide multiple services care about both transparency of ATM 
service (e.g. proper placement of OAM cells, carriage of AAL-5 trailer 
fields) and efficiency of that service.

Hence, we seem to have several applications for ATM-MPLS network 
interworking.  What we have been arguing is that if these multiple 
applications have different requirements, then the encapsulations should be 
tailored to those differing requirements.

Jim Harford

---

From: Robert Raszuk <[email-masked]>
Date: Mon, 06 May 2002 22:51:21 +0200

Hi Jim,

I hate to paticipate in never ending threads like this one, but I think
I am pretty close to finding out the src of confusion here :) ..

> Some of the participants on this list are in 
> services, where the data is presumed to be IP.

I think you are refering to those SPs who have IP-MPLS netowrk and not
ATM-MPLS one. This is a huge difference. I hope those who have IP-MPLS
based net today don't have huge expectations what with a few line of C
or microcode or even new ASIC will be able to become carriers offereing
TDM :).

> In contrast, the carriers 

True - but nothing will prevent those carriers which use ATM as their
main transport to continue doing so and in the same time provide
scalable data (yes mostly IP) transport over ATM-MPLS. I do know at
least two vendors offering such an option to their ATM gear today. I
don't want to name examples of those doing so today but I am sure you
and other know them. Other on the other hand are really builing a
parallel to their ATM core IP network for data services and migration of
those user's traffic like Luca's where entire corporations are moving
mostly for cost savings reasons to IP based voice, teleconferencing and
other services. 

> legacy protocol.  This is an IP world."

So to conclude I am afraid to agree with this comment. Why IP world
should bother with dying technology where both can coexist just fine if
needed ? 

R.

---

From: Jim Harford <[email-masked]>
Date: Mon, 06 May 2002 18:40:11 -0400

Robert,
I didn't quite follow all of your logic, but the impression I'm getting 
from you is that PWE3 is meant only for those SPs who have an IP-MPLS 
network and do not plan to offer a service conforming to ITU's definition 
of ATM.  If that is the case, let's make sure we help the industry 
understand that by carefully describing the applicability statements for 
the encapsulation.

The ATM Forum's solution is clearly oriented toward carriers that are using 
ATM to provide multiple services.  The industry needs to understand the 
different capabilities of the PWE3 work versus the ATM Forum's specification.

Jim Harford

---

From: Giles Heron <[email-masked]>
Date: 07 May 2002 10:34:00 +0000

> understand that by carefully describing the applicability statements for 

Hi Jim/Robert,

I think there are actually two statements here:

1.  PWE3 is meant only for SPs with IP-MPLS networks.

2.  PWE3 is not meant to offer a service conforming to the ITU-T's
definition of ATM.

I would say that neither statement is true.

With respect to the first statement I would say, however, that ATM PWE3
is probably not a likely application for SPs running MPLS-ATM networks. 
ATM over PWE3 over MPLS over ATM seems unlikely to be deployed in large
amounts?  I may be wrong here - after all Ethernet over PWE3 over MPLS
over Ethernet is commonly deployed (in my network and in many others). 

With respect to the second statement I would say that (efficiency
arguments notwithstanding) the cell mode of either draft-brayley or
draft-fischer is ideal for offering service conforming to the ITU-T's
definition of ATM?

Giles
 
-- 
=================================================================
Giles Heron    Principal Network Architect    PacketExchange Ltd.
ph: +44 7880 506185              "if you build it they will yawn"
=================================================================

---

From: Robert Raszuk <[email-masked]>
Date: Tue, 07 May 2002 13:27:11 +0200

Hi Giles,

> over Ethernet is commonly deployed (in my network and in many others).

I fully agree - so why not to make things simple and say directly that
complicating the protocol to address something that will most likely be
never deployed in production is just a bit of waist of time :) ?

I guess at this point we would need at least of few commited SPs of
significant size which would indicate to the group their desire to do
ATM over PWE3 over MPLS over ATM otherwise I would propose to close this
topic.

R.

> Giles Heron wrote: