RE: AW: [EFM] PON Optics Telephone Conference, December 5th
Richard,
Controlling jitter over an Ethernet network is a project that we support in
other forums than 802.3ah. My comment and question was attempting to
gather more information in the debate over common PMD timing specifications.
If the Options A-D in the debate of PON timing have different possible
services enabled, I think that is a fair question to ask on this exploder.
I don't support multiple Gigabit PON timing specifications each one for a
only subset of potential service applications.
Thanks,
-Kent
> -----Original Message-----
> From: Richard Brand [mailto:rbrand@nortelnetworks.com]
> Sent: Friday, December 06, 2002 12:34 PM
> To: Roy Bynum
> Cc: kmccammon@tri.sbc.com; stds-802-3-efm@ieee.org
> Subject: Re: AW: [EFM] PON Optics Telephone Conference, December 5th
>
>
> Roy:
> So here we go. I agree with everything you state except that
> Kent did not ask about "Leased Circuit Private Line services
> " or "Ethernet Private Line" but about T1 services over a
> draft 802.3 P2MP network. In addition Ethernet private line
> or leased line services are just as much out of scope for
> 802.3 as is TDM based T1 services. That's why we have taken
> on that work in the MEF with a close liaison to the ITU work
> to which you make reference. That also gets into
> encapsulation, but that is surely out of scope for .3.
> Therefore, I am correct in saying that your message did not
> answer his question. I do believe Arial's note makes an
> attempt to address the efficiency question, but I
> believe that the potential for added jitter is real. It is
> however, out of scope
> for .3. Kent, any comments?
> Regards,
> Richard
>
>
> Roy Bynum wrote:
>
> > Richard,
> >
> > You are incorrect. 802.3 in and of itself can NOT be used
> to provide
> > Leased Circuit Private Line services. I am the author of
> the term and
> > definition of "Ethernet Private Line" services. Ethernet
> Private Line
> > is based on SONET/SDH, not 802.3
> >
> > ITU standards for leased circuit private line services specifically
> > states that the customer of the leased circuit has exclusive use of
> > the circuit facility. This is in contrast to "packet"
> services that do
> > emulation via a "virtual" circuit. Since 802.3ah PON does
> not provides
> > virtual circuit emulation via the frame "header", called a
> "preamble"
> > by 802.3 and not any type of physical or time based facilities
> > segregation, it falls under the category of a
> "packet/frame" service
> > technology, not a leased circuit service technology.
> >
> > The existing ITU standards already provides for permanent virtual
> > circuit emulation at fixed bandwidths over packet/cell
> based services.
> > These can be at T1 or any other fixed bandwidth. The ITU standards
> > makes a specific distinction between the "leased circuit"
> services and
> > the emulated circuit services over packet/cell/frame transport
> > protocols.
> >
> > I didn't write the ITU standards. I just spent the last year that I
> > was at Worldcom researching the specifics of defined standards for
> > different types of data communications services.
> >
> > 802.3 in and of itself does not provide leased circuit private line
> > services. The fact that a single customer using 802.3 can be
> > provisioned as the only customer on a "dark" fiber, makes the dark
> > fiber, a leased circuit private line service, not the 802.3. This
> > format would also hold for 802.3ah copper facilities that
> are used by
> > a single customer.
> >
> > The service "Ethernet Private Line" is not based on an
> 802.3 standard,
> > other than it provides a "mapping" for Ethernet frames. The
> ITU x.86
> > "Ethernet over LAPS" provides for "mapping" of Ethernet frames into
> > SONET/SDH by replacing the IFG/Preamble with LAPS, a HDLC
> derivative
> > and then using TDM nature of SONET/SDH to provision the
> service as a
> > standard leased circuit facility. This would also hold for g.GFP.
> >
> > Thank you,
> > Roy Bynum
> >
> > At 02:40 PM 12/5/2002 -0800, Richard Brand wrote:
> > >Thomas:
> > >I would offer that Roy's note does not answer question 1
> and I have
> > >sent a note to Roy to detail. As Kent is aware, there is
> an ongoing
> > >project in the MEF right now to specify circuit services (read TDM
> > >including T1) over Ethernet including 802.3 networks.
> > >The timing issue could be critical to some implementations
> and is one of the
> > >reasons I voted "no" in Kauai. Vipal, do you want to take it on?
> > >Regards,
> > >Richard Brand
> > >
> > >
> > >
> > >Thomas.Murphy@infineon.com wrote:
> > >
> > > > Hi Kent,
> > > >
> > > > Thanks for your input on this topic. I believe that question 1)
> > > > has already been addressed by Roy Bynum; there are
> others who are
> > > > in a better position to answer this than me.
> > > >
> > > > Regarding testing I see two different levels/types of testing.
> > > > Firstly there is module testing where different response times
> > > > will not present a problem (the response time is
> probably one of
> > > > the parameters that would be determined). Beyond this there is
> > > > then system/interoperability testing. When testing with
> > > 'non-intelligent'
> > > > equipment, the guardband between bursts would be set to the
> > > > Upper-Bound values agreed upon. By guardband I mean the
> time delay
> > > > between the Tx_On signal and the time when the Rx
> starts examining
> > > > bit to determine the BER. With an intelligent system, i.e.
> > > > protocol implementation with negotiated parameters,
> > > > interoperability is not a problem as the optimal
> guardband is calculated.
> > > >
> > > > The above tests determine if one Tx communicates optically with
> > > > the
> > > expected
> > > > BER
> > > > with another Rx. Setting the guardband equal to the upper limit
> > > > determines that the timing requirements of the combined
> link are
> > > > met. Direct module testing delivers the individual Rx and Tx
> > > > times. Hence, I don't see a problem with testing
> depending on the
> > > > option choice for the timing parameters.
> > > >
> > > > Regards
> > > >
> > > > Tom
> > > >
> > > > -----Ursprüngliche Nachricht-----
> > > > Von: Mccammon, Kent G. [mailto:kmccammon@tri.sbc.com]
> Gesendet am:
> > > > Donnerstag, 5. Dezember 2002 02:45
> > > > An: Murphy Thomas (COM FO D O); stds-802-3-efm@ieee.org;
> > > > Vipul_Bhatt@ieee.org; wdiab@cisco.com
> > > > Betreff: RE: [EFM] PON Optics Telephone Conference, December 5th
> > > >
> > > > Tom,
> > > > Since I have a conflict with the call tomorrow and I am
> interested
> > > > in this decision, here are some questions.
> > > >
> > > > 1)Do any of the options for PON timing impact the delivery of
> > > > services such as toll quality voice, a T1, or multicast
> video? We
> > > > had this concern previously and the answer previously
> was claimed
> > > > to be only an efficiency hit for loose timing. Are the modeling
> > > > assumptions to compare efficiency valid for TDM services or is
> > > > that not a consideration in this debate to date? 2)The
> negotiation
> > > > of timing parameters rather than a tight specification have any
> > > > impact on future interoperability testing? If we ever
> decide to
> > > > test interoperability of EPON OLT and ONT, can a lab testing
> > > > system be reasonably built to test compliance to a
> specification
> > > > for OLT/ONT timing for the various options under debate? 3)Do
> > > > operating temperature swings have an impact on timing
> options. Is
> > > their
> > > > reason to add extra margin or extra negotiation time of timing
> > > > parameters due to temperature variations? What about
> cold start in
> > > > cold temperatures, that was an issue for power levels, does it
> > > > also impact the electronics of the PMD?
> > > >
> > > > Comment: As an advocate of PON technologies I echo my earlier
> > > > comments
> > > about
> > > > striving for common PON PMD to get the volume started in today's
> > > economy. I
> > > > am optimistic a compromise can be found in January. Thanks,
> > > > -Kent
> > > >
> > > > > -----Original Message-----
> > > > > From: Thomas.Murphy@infineon.com
> > > > > [mailto:Thomas.Murphy@infineon.com]
> > > > > Sent: Wednesday, December 04, 2002 10:12 AM
> > > > > To: stds-802-3-efm@ieee.org; Vipul_Bhatt@ieee.org;
> wdiab@cisco.com
> > > > > Subject: [EFM] PON Optics Telephone Conference, December 5th
> > > > >
> > > > >
> > > > > Hello Again,
> > > > >
> > > > > Attacted two possible approaches to this discussion
> forming two
> > > > > decision trees. Glen and I worked on these I I did not have a
> > > > > chance to co-ordinate with him and refine to one slide. The
> > > > > first slide is mine and I would like to start here as
> it allows
> > > > > us to generate values without having to make
> decisions. When the
> > > > > values are agreed upon, we can work towards the decision and
> > > > > perhaps this is simpler with the values we have.
> > > > >
> > > > > If this does not work, we can try the seconf slide, Glen's
> > > > > approach, which is a more top-down attack.
> > > > >
> > > > > Talk to you tomorrow
> > > > >
> > > > > Tom
> > > > >
> > > > > <<PON Timing Decision Tree.ppt>>
> > > > >
> > > > > Hello All,
> > > > >
> > > > > Items to Be Covered
> > > > >
> > > > > 1) Determine the exact meaning of the terms "Fixed
> Value" and
> > > > > 'Upper Bound" in terms
> > > > > of their use for PMD timing parameters.
> > > > >
> > > > > 2) Try assign placeholder values for all of the options
> > > > >
> > > > > 3) Are these values fixed or bounded for the
> different options.
> > > > >
> > > > > 4) Other items
> > > > >
> > > > > Regards
> > > > >
> > > > > Tom
> > > > >
> > > > >
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