Subject: [PWE3] Inter-op is not necessary

From: Andy Li <[email-masked]>
Date: Thu, 10 Nov 2005 17:21:51 -0800

Hi,

  I don't think it is necessary to have both signaling mechanism for
MS-PW inter-op with each other. If two providers agree to peer with
each other to provide PW services, it will be a bonus if they two use
the same mechanism to set up PW circuits. If not, the business
interests will encourage them to stitch the PW circuits by using
back2back logical/virtual interface(s) or even a jumper fiber between
ODF.

  Therefore, out of my own opinion, the inter-op requirement should be removed.

Best
Andy Li

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https://www1.ietf.org/mailman/listinfo/pwe3

---

From: Shane Amante <[email-masked]>
Date: Thu, 10 Nov 2005 18:51:16 -0800

I disagree.  The problem with the approach you suggest in your last 
sentence below is it's very manually intensive (read: non-dynamic) in 
terms of provisioning (adds, changes, decomm's) of MS-PW's between two 
domains.  I would much rather have a dynamic MS-PW protocol running 
across a Carrier<->Carrier interface, than humans stringing cables in 
patch panels.   Therefore, IMO (as an SP), MS-PW interop is extremely 
important thing to figure out before we go much further down the path of 
MS-PW and vendors start to implement pre-standard, non-interoperable 
versions of MS-PW creating [even more of] a mess for SP's.

Furthermore, let's not forget that one of the significant downsides to 
two, separate MS-PW protocols (that do not interoperate) is that some 
carriers will get locked into one vendor who only implements MS-PW 
protocol "A", while the rest of the market/carriers have chosen MS-PW 
protocol "B".  Or, carriers tell vendors to implement both, (because 
they don't want lock-in), which begs the question of why didn't we just 
choose one in the beginning?  At the risk of stating the obvious, why 
can't we just apply the 80/20 rule in deciding which one of the 
protocols is best, (a.k.a.: "least-evil"), and move forward with it, 
rather than cycling on two protcols simultaneously and figuring out 
various interactions/interoperation between the two?

In the end, it is my hope that the WG does ultimately decide on *one* 
MS-PW protocol in order to avoid confusion in the marketplace which 
ultimately will hurt not only vendors, but also SP's and SP's customers.

My $0.02,

-shane

---

From: Mark Townsley <[email-masked]>
Date: Thu, 10 Nov 2005 19:12:09 -0800

To be clear, I said that "coexistance" was a necessity to be documented 
by the WG. Whether coexistance equates to interworking depends on the MS 
requirements.

If the WG decides that providers would rather operate in a "10a" model 
(to use l3vpn terminology) rather than switch directly from one PW to 
another, coexistance is possible without interworking between LDP and 
RSVP. If this is true, however, it does beg the question as to whether 
interprovider MS is truly necessary at all.

- Mark

---

From: Andy Li <[email-masked]>
Date: Fri, 11 Nov 2005 00:38:50 -0800

Shane

Not arguing with you. Jumper cables between ODF(DDF) has been however a fact
for SP to provision circuits ever since the first day the lease line (called
DDN in China) was introduced. I also admit it was part of the reason why SP
wanna get rid of it and replace it with CES back in late 1990 in order to
cut OPEX. We are now just trying to do it again with either GMPLS signaled
devices, i.e. MSTP/MSPP or PW over bandwidth-rich IP backbone(s). In fact,
we do have a customer today which runs provisioning three times in order to
provide MS-PW over two-tier backbone (provincial-national-provincial)! While
we wait for the standard(s), jumper cable between ODF(DDF) is the best
practice.

I sometimes wonder why SP is still working with us (vendors) to define their
secret weapons (aka new telecom services). Back in the old days, AT&T would
have probably implemented it in their own lab so that they could have OPEX
advantage over other carriers. I guess neither IETF nor any of us has the
responsibility promoting fair competition. Let market decide which one will
be the least-evil if there is one.

Best
Andy Li

PS. I think fair competition kills AT&T :-)))

---

From: Andy Li <[email-masked]>
Date: Sat, 12 Nov 2005 12:00:39 -0800

Please also take the trend of global telecommunication providers into
picture. The MS-PW job done so far has already help out quite a bit.
We should just leave the rest to the providers which, by the way, have
their focus more on profitability but signaling inter-op.

My 0.02
Andy

On 11/11/05, Andy Li <[email-masked]> wrote:
> Shane
>
>    Not arguing with you. Jumper cables between ODF(DDF) has been however a
> fact for SP to provision circuits ever since the first day the lease line
> (called DDN in China) was introduced. I also admit it was part of the reason
> why SP wanna get rid of it and replace it with CES back in late 1990 in
> order to cut OPEX. We are now just trying to do it again with either GMPLS
> signaled devices, i.e. MSTP/MSPP or PW over bandwidth-rich IP backbone(s).
> In fact, we do have a customer today which runs provisioning three times in
> order to provide MS-PW over two-tier backbone
> (provincial-national-provincial)! While we wait for the
> standard(s), jumper cable between ODF(DDF) is the best practice.
>
>    I sometimes wonder why SP is still working with us (vendors) to define
> their secret weapons (aka new telecom services). Back in the old days, AT&T
> would have probably implemented it in their own lab so that they could have
> OPEX advantage over other carriers.  I guess neither IETF nor any of us has
> the responsibility promoting fair competition. Let market decide which one
> will be the least-evil if there is one.
>
>  Best
>  Andy Li
>

---

From: David McDysan <[email-masked]>
Date: Fri, 18 Nov 2005 08:00:37 -0500

I disagree with this proposal to remove interoperation of MS-PW signaling
protocols from the  requirements draft. There is already an implied
requirement for interoperation of already defined protocols in section 6.4
of http://ietf.org/internet-drafts/draft-ietf-pwe3-ms-pw-requirements-01.txt

IMO, what we are discussing is how many more protocols we will eventually
add to this section and how these protocols will need to interoperate. As
stated in section 6.4, a specific implementation (or operator) may not
implement all of these protocols. For the inter-operator case, I think we
should strive to have a small set of protocols that are recommended for such
use.

In my view, some of the protocols and procedures are more applicable to
certain network deployments than others. As I suggested in the meeting last
week, the solution drafts should contain an expanded applicability section
that describes the use cases of section 5 of the MS-PW requirements that it
addresses.

Dave

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On 
> Behalf Of Andy Li
> Sent: Thursday, November 10, 2005 8:22 PM
> To: [email-masked]
> Subject: [PWE3] Inter-op is not necessary
> 
> Hi,
> 
>   I don't think it is necessary to have both signaling 
> mechanism for MS-PW inter-op with each other. If two 
> providers agree to peer with each other to provide PW 
> services, it will be a bonus if they two use the same 
> mechanism to set up PW circuits. If not, the business 
> interests will encourage them to stitch the PW circuits by 
> using back2back logical/virtual interface(s) or even a jumper 
> fiber between ODF.
>

---

From: David McDysan <[email-masked]>
Date: Fri, 18 Nov 2005 08:00:37 -0500

IMO, we already have a "l3vpn 25457bis option" a capability with single
segment PWs. In other contexts (e.g., FR, ATM), this has interconnection
case has been called a "back-to-back UNI." Since there is no alternate path
in such back-to-back SS-PWs, this is not an acceptable solution from a
service provider point of view. This is why service providers and others
have created the requirements in
http://ietf.org/internet-drafts/draft-ietf-pwe3-ms-pw-requirements-01.txt.

For these reasons, I believe that "co-existence" as defined in this note is
a not a MS-PW requirement.

This

Dave 

> Behalf Of Mark Townsley
> Sent: Thursday, November 10, 2005 10:12 PM
> To: Andy Li
> Cc: [email-masked]
> Subject: Re: [PWE3] Inter-op is not necessary
> 
> 
> To be clear, I said that "coexistance" was a necessity to be 
> documented by the WG. Whether coexistance equates to 
> interworking depends on the MS requirements.
> 
> If the WG decides that providers would rather operate in a 
> "10a" model (to use l3vpn terminology) rather than switch 
> directly from one PW to another, coexistance is possible 
> without interworking between LDP and RSVP. If this is true, 
> however, it does beg the question as to whether interprovider 
> MS is truly necessary at all.
> 
> - Mark
> 
> Andy Li wrote:
> 
> >Hi,
> >

---

From: Mark Townsley <[email-masked]>
Date: Fri, 18 Nov 2005 15:19:32 +0100

>a not a MS-PW requirement.

"Coexistance" is simply a word I made up to mean that if the WG decides 
to advance two proposals, it must recognize that both exist and what it 
is going to do about it. It isn't an MS or Provider requirement, it is a 
Working Group requirement. The WG MUST adequately address all of the 
complexities of advancing more than one solution if it decides to do so.

Dealing with this reality of coexistance will require the working group 
to define mechanisms based on MS-PW requirements. You have stated that 
interworking with SS-PWs is one such requirement. I agree, so in our 
minds if two proposals advance, then the WG will have to define 
interworking mechanisms between SS-LDP and MS-LDP as well as SS-LDP and 
MS-RSVP. Interworking between MS-LDP and MS-RSVP will depend on whether 
interoperating providers are willing to either (1) support both 
signalling types in their network, or (2) agree to peer only with those 
providers who choose their preferred protocol. You can't have both 
without interworking between the two.

- Mark

>>>each other to provide PW services, it will be a bonus if 
>>>      
>>>
>>they two use 
>>    
>>
>>>back2back logical/virtual interface(s) or even a jumper 
>>>      
>>>
>>fiber between 
>>    
>>
>>>ODF.
>>>
>>> Therefore, out of my own opinion, the inter-op requirement 
>>>      
>>>
>>should be removed.
>>    
>>
>>>Best
>>>Andy Li
>>>

---

From: David McDysan <[email-masked]>
Date: Fri, 18 Nov 2005 11:52:03 -0500

Mark,

Thanks for the clarification on terminology. 

IMO, if the WG decides to advance both MS-LDP and MS-RSVP, then these need
to be designed interoperate as well.

Dave

> Sent: Friday, November 18, 2005 9:20 AM
> To: David McDysan
> Cc: [email-masked]
> >segment PWs. In other contexts (e.g., FR, ATM), this has 
> >interconnection case has been called a "back-to-back UNI." 
> Since there 
> >is no alternate path in such back-to-back SS-PWs, this is not an 
> >acceptable solution from a service provider point of view. 
> This is why 
> >service providers and others have created the requirements in 
> >For these reasons, I believe that "co-existence" as defined in this 
> >note is a not a MS-PW requirement.
> >  
> >
> 
> "Coexistance" is simply a word I made up to mean that if the 
> WG decides to advance two proposals, it must recognize that 
> both exist and what it is going to do about it. It isn't an 
> MS or Provider requirement, it is a Working Group 
> requirement. The WG MUST adequately address all of the 
> Dealing with this reality of coexistance will require the 
> working group to define mechanisms based on MS-PW 
> requirements. You have stated that interworking with SS-PWs 
> is one such requirement. I agree, so in our minds if two 
> proposals advance, then the WG will have to define 
> interworking mechanisms between SS-LDP and MS-LDP as well as 
> SS-LDP and MS-RSVP. Interworking between MS-LDP and MS-RSVP 
> will depend on whether interoperating providers are willing 
> to either (1) support both signalling types in their network, 
> or (2) agree to peer only with those providers who choose 
> their preferred protocol. You can't have both without 
> interworking between the two.
> 
> - Mark
> 
> >This
> >
> >Dave
> >
> >  
> >
> >>From: [email-masked] [mailto:[email-masked]] 
> On Behalf 
> >>Of Mark Townsley
> >>documented by the WG. Whether coexistance equates to interworking 
> >>depends on the MS requirements.
> >>
> "10a" model 
> mechanism for