Subject: New draft: draft-ietf-issll-ds-map-00.txt

From: John Wroclawski <[email-masked]>
Date: Wed, 15 Mar 2000 17:05:09 -0500

Folks,

Anna Charny and I have written a very drafty first draft of a 
"service mapping" document for diffserv. The purpose of this document 
is to describe the specifics of using diffserv clouds as part of a 
path that provides end-to-end intserv-style QoS.

I haven't seen the IETF announcement of this draft go by the list 
yet, but I assume it will soon. In the meantime it is available at

http://ana.lcs.mit.edu/ISSLL/drafts/draft-ietf-issll-ds-map-00.txt
ftp://ana.lcs.mit.edu/ISSLL/drafts/draft-ietf-issll-ds-map-00.txt

Completing this document is the last big thing in the group's current charter.
However, it needs quite a bit of work still, including the writing of 
at least one or two sections that are entirely missing at this point. 
All help from quick comments to additional authors would be welcome.

We've allocated a good chunk of the Adelaide meeting to presenting 
and discussing this draft. We hope to spin a new version very shortly 
after the meeting based on discussion there and on the list, so 
please take a look now if you're interested in this.

Thanks,
John

---

From: John Wroclawski <[email-masked]>
Date: Fri, 17 Mar 2000 16:26:21 -0500

([email-masked] added to the reply list)

Jon,

At 9:09 AM +0000 3/16/00, Jon Crowcroft wrote:
>In message <v04210102b4f5b1e1121a@[18.26.0.167]>, John Wroclawski typed:
>
>yes - i wonder if
>ftp://ftp.ee.lbl.gov/papers/vw_ba.pdf
>isnt relevant.....
>
>there's an assretion in kathy's paper that the jitter preopbability
>decreases as negative exponential of the number of the hops (as well
>as increasing linearly) due to the number of different ways you can
>combine DE packets to get infront of VW packets.....its a bit
>simplistic but clearly in the right spirit of working out what we
>actually care about, which (imho) is not worst bounds but 90centiles
>or first couple of moments of the delay distribution

This all is the intent of (the unwritten, only a title there at the 
moment) Section 5. We are definitely in need of contributions in this 
area.

What we wanted to accomplish with Section 4 was to lay out the 
performance of a "real" guaranteed service, and particularly give 
some intution about how it varies with changes in topology and so on.

Of course, we have a service (CL) that is specifically intended to 
support and be implemented with 99.99% strategies. So probably we've 
got the structure of the draft a bit wrong; a discussion of this 
could be broken out as service independent and then the applicability 
of it to both CL and G discussed separately.

>so the straight negative exponential assumes poisson (independant)
>phases of the seperate flows merging at an egress bottleneck. i you
>put in other distributions, and even put in a feedback loop that tends
>to synch the flows, its still quite hard to get a system that spends
>much of its time at the worst case.....but i think someone with some
>fancy stats background should look at these - feedin some fractional
>arima, and some renewal process stuff, and see what happens...

John