Subject: RE: WG last call: draft-ietf-tewg-diff-te-russian-02.txt

From: "Lai, Wai S (Waisum), ALABS" <[email-masked]>
Date: Mon, 21 Apr 2003 11:27:36 -0500

Francois,
   This message addresses Comment 1 in your message
http://ops.ietf.org/lists/te-wg/te-wg.2003/msg00228.html
as it relates to the Russian Dolls draft Last Call.

   Your following statement in the above message correctly reflects my
intent:
"Now, if I understand correctly, the approach you took for selecting BC
vales for RDM, was to pick BC values so that RDM would exhibit the same
blocking probabilities as MAM for a given reference LSP load."

  However, this statement is incorrect with respect to my comparison:
"For example, these values would accept a total load of 6+7+15=28
with MAM , while the maximum load is limited to BC3=15 with RDM."

  In <draft-wlai-tewg-bcmodel>, first of all, both MAM and RDM are
being offered the same load: 2.7 + 3.5 + 3.5 units as stated on the
top of page 5.  Furthermore, it is stated that
"As an example, consider a link with a capacity that allows a maximum 
of 15 LSPs from different classes to be established simultaneously.  
Overbooking is allowed, ..."
  Also, 
"bandwidth constraints (for MAM) are: 
up to 6 simultaneous LSPs for class 1,
up to 7 simultaneous LSPs for class 2, and 
up to 15 simultaneous LSPs for class 3."

  Note the wording "up to."  Thus, while it is true that the sum of
*maximum* bandwidth constraints can add up to 28, there can be no
more than 15 *simultaneous* LSPs allowed for all classes, since
this is the ultimate constraint imposed by the link capacity
(which is the same link for both MAM and RDM).
Thus, using your terminology in the above message, both MAM and RDM
in my draft are either (1) both are Porsches, or (2) both are backed
up by 3-ton-trailers.

  Per your request, the attached diagram shows the result for the
case you suggested for RDM: BC1=6, BC2=13, and BC3=28.  Comparing
this result with Figures 1 and 2 in <draft-wlai-tewg-bcmodel>,
it can be seen that the QoS degradation for class 1 is the same in
all three cases, even though the link capacity is now 28 is your case,
and 15 in the other two cases in my draft.

  This is contrary to the following claim made in
<draft-ietf-tewg-diff-te-russian-02.txt>:
"RDM can be used to simultaneously ensure bandwidth efficiency 
and protection against QoS degradation of all Class-Types"

Thanks, Wai Sum

-----Original Message-----
From: Jim Boyle [mailto:[email-masked]]
Sent: Tuesday, April 08, 2003 10:51 AM
To: [email-masked]
Subject: WG last call: draft-ietf-tewg-diff-te-russian-02.txt

http://www.ietf.org/internet-drafts/draft-ietf-tewg-diff-te-russian-02.t
xt

This is WG last call for this draft to be advanced as expiremental RFC.

Last call ends in 2 weeks (4/22).

thanks,

Jim Boyle

---

From: "Francois Le Faucheur (flefauch)" <[email-masked]>
Date: Tue, 22 Apr 2003 17:52:12 +0100

Waisum,

So the bottom line is that we assumed different definitions for MAM.
Your analysis assumed the model recently discussed on the list (ie "MAM
with the additional implied bandwidth constraint") as opposed to MAM as
currently defined. We do need to make some decision on this issue. And
then your analysis should be based on the outcome of that discussion.

Let me think more about the MAM definition issue.

Cheers

Francois

PS: What I mean by QoS degradation does not relate to blocking
probability. It refers to ensuring that the maximum amount of
established LSPs for a given CT is in line with the service rate that
the scheduler can provide to that CT. Please see the draft I issued a
while back on "BC Model considerations".

>> From: Lai, Wai S (Waisum), ALABS [mailto:[email-masked]] 
>> Sent: 21 April 2003 18:28
>> To: Francois Le Faucheur (flefauch)
>> Cc: Jim Boyle; [email-masked]
>> Subject: RE: WG last call: draft-ietf-tewg-diff-te-russian-02.txt
>> 
>> 
>> Francois,

thanks,

Jim Boyle

---

From: "Francois Le Faucheur (flefauch)" <[email-masked]>
Date: Fri, 25 Apr 2003 14:08:11 +0100

Jim,

The enhancement to the MAM definition that we're discussing has ripple
effects into -proto and into -russian (BTW from memory I think that
would address part, or all, of Waisum's comment).

So I would suggest issueing a new rev of -proto and -russian with the
corresponding edits before posting to IESG. I could post those fairly
quickly once we've concluded on the MAM definition on the list.

Makes sense?

Cheers

Francois

>> Sent: 24 April 2003 21:38
>> To: [email-masked]
>> Subject: Re: WG last call: draft-ietf-tewg-diff-te-russian-02.txt
>> 
>> 
>> 
>> This WG last call has ended.  There was one comment by 
>> Waisum, I don't 
>> think it was to object to this document.
>> 
>> Therefore this document is completed for WG discussion at this time.
>> 
>> It will be forwarded to IESG with the PROTO draft, which is 
>> through the 
>> 2nd week of it's 3 week WG last call.  
>> 
>> thanks,
>> 
>> Jim
>> 
>> On Tue, 8 Apr 2003, Jim Boyle wrote:
>> 
>> > 
>> > 
>> > 
>> http://www.ietf.org/internet-drafts/draft-ietf-tewg-diff-te-r
ussian-02.txt

---

From: "Lai, Wai S (Waisum), ALABS" <[email-masked]>
Date: Fri, 25 Apr 2003 14:01:34 -0500

Francois,
   Since definitional issues of MAM are being addressed in
another thread, I've responded there.

   Based on your response below regarding QoS degradation in
RDM, I think some clarification is needed.  After the following
statement in page 5 of <draft-ietf-tewg-diff-te-russian-02.txt>:
"RDM can be used to simultaneously ensure bandwidth efficiency 
and protection against QoS degradation of all Class-Types"

something along the following line should be added:
"However, this may incur increased LSP blocking probability as
the maximum amount of established LSPs for a given CT needs to
be kept in line with the service rate that the scheduler can
provide to that CT."

Thanks, Wai Sum

-----Original Message-----
From: Francois Le Faucheur (flefauch) [mailto:[email-masked]]
Sent: Tuesday, April 22, 2003 12:52 PM
To: Lai, Wai S (Waisum), ALABS
Cc: [email-masked]
Subject: RE: WG last call: draft-ietf-tewg-diff-te-russian-02.txt

Waisum,

Cheers

Francois

thanks,

Jim Boyle

---

From: "Lai, Wai S (Waisum), ALABS" <[email-masked]>
Date: Fri, 25 Apr 2003 14:12:14 -0500

Jim,
  I think the issue that was brought up by my comment during the Last
Call needs resolution and requires a response in the current I-D.
Thanks, Wai Sum

-----Original Message-----
From: Jim Boyle [mailto:[email-masked]]
Sent: Thursday, April 24, 2003 3:38 PM
To: [email-masked]
Subject: Re: WG last call: draft-ietf-tewg-diff-te-russian-02.txt

This WG last call has ended.  There was one comment by Waisum, I don't 
think it was to object to this document.

It will be forwarded to IESG with the PROTO draft, which is through the 
2nd week of it's 3 week WG last call.  

thanks,

Jim

On Tue, 8 Apr 2003, Jim Boyle wrote: