Re: A PHB question

The issue of delay and jitter in relation to the AF PHB 
arose when the Assured Rate PDB was first discussed.
The draft has now expired but can be found at old id repositories:

http://www.ietf.org/proceedings/01dec/I-D/draft-ietf-diffserv-pdb-ar-01.txt

See the thread surrounding this one for the evolution of the
discussion: 

http://www1.ietf.org/mail-archive/working-groups/diffserv/current/msg02805.html

As a result of mailing list discussion, the AR PDB draft was 
modified so that it stated the following:

 "It may be possible to determine delay and jitter bounds  
  for  traffic aggregates  using the AR PDB. However, such 
  parameters are beyond the scope of this PDB definition and 
  no attempt is made  to  characterize them. Development of a 
  mathematical model to predict delay and jitter for the  
 AR  PDB  is  left  as  a  subject  of  future  research  and
 investigation."

Best,
Nabil Seddigh
[email protected]




Ali badilli wrote:
> 
> Hi,
> 
> That's right. Delay is not a parameter of AF.
> But I am just wondering if none of AF classes defines
> delay, delay jitter bounds, then how a PDB, which is
> built from particular PHB,can defines bounds for
> delay, delay jitter? (not assuming EF)
> 
> Thanks,
> 
> Ali
> 
> --- Brian E Carpenter <[email protected]> wrote:
> > The answer is clearly yes; all routers along the
> > path need appropriate
> > configuration.
> >
> > However, maximum delay is not a parameter of AF as
> > far as I know.
> >
> > It would be best to continue this discussion on the
> > diffserv
> > implementation list.
> > http://www.tip.csiro.au/dsimplementation/
> >
> >   Brian Carpenter
> >   diffserv co-chair
> >
> >
> > Ali badilli wrote:
> > >
> > > Hi,
> > >
> > > Does a particular PHB requires same constraints
> > from
> > > each router within the domain?,
> > >
> > > For example, let say we configure router A to make
> > > maximum delay for AFxy (PHBxy) 1 ms. Do other
> > routers
> > > need to be configured in same way to have 1 ms
> > maximum
> > > delay for AFxy?
> > >
> > > The question is only for AF PHB, EF is clear.
> > >
> > > Thanks
> > >
> > > __________________________________________________
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> http://www.ietf.org/mail-archive/working-groups/diffserv/current/maillist.html
> >
> > --
> > - - - - - - - - - - - - - - - - - - - - - - - - - -
> > - - - - - - -
> > Brian E Carpenter
> > Distinguished Engineer, Internet Standards &
> > Technology, IBM
> > On assignment at the IBM Zurich Laboratory,
> > Switzerland
> >
> > _______________________________________________
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> > [email protected]
> > https://www1.ietf.org/mailman/listinfo/diffserv
> > Archive:
> >
> http://www.ietf.org/mail-archive/working-groups/diffserv/current/maillist.html
> >
> 
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> 
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