Re: [EFM] Re: [EFM-OAM] New update on EFM OAM Work Item #3

[Bob Gaglianello <rdg@xxxxxxxxxx>]

Hello All,

Speaking from my understanding, every time an ONU starts tansmitting, 
the OLT will have to re-lock.

cheers,
bobg

P.S. LLID's are needed to provide compliance with 802.1D bridges....

Ben Brown wrote:
> 
> Vipul,
> 
> This question is slightly off topic. This is why I've opened it up
> to the wider EFM audience.
> 
> In EPON, there are multiple ONU's sending data up to a 1000BASE-X OLT.
> Each ONU transmits for a few microseconds each. Is there a guarantee
> that the OLT won't lose sync with the 8B/10B commas when ONU's switch
> in and out? Is it expected that the OLT will lose and regain sync with
> each ONU switch over?
> 
> Perhaps this is well understood and you can simply point me to a
> presentation that describes this process.
> 
> Regards,
> Ben
> 
> Vipul Bhatt wrote:
> 
>>Ben,
>>
>>I am sure MAC Control at OLT end knows at each moment which ONU is
>>talking. But I am worried that if it has just one PCS error counter
>>to read from, it won't be able to discern useful information from
>>it. Error rates need averaging over several seconds to become a
>>stable value. With ONUs taking turns to transmit, each one for a few
>>microseconds, it will be difficult to get a reliable indication of
>>error rate of an individual link.
>>
>>I will request some P2MP colleagues to answer your questions better.
>>Like Hugh, I am tempted to crawl back to my photonic cave...
>>
>>Vipul
>>
>>================
>>
>>
>>>-----Original Message-----
>>>From: owner-stds-802-3-efm-oam@majordomo.ieee.org
>>>[mailto:owner-stds-802-3-efm-oam@majordomo.ieee.org]On
>>>Behalf Of Ben
>>>Brown
>>>Sent: Tuesday, July 23, 2002 7:24 AM
>>>To: Hugh Barrass
>>>Cc: Vipul_Bhatt@xxxxxxxx; Kevin Daines;
>>>stds-802-3-efm-oam@ieee.org;
>>>ambraga@xxxxxxxxxxx; tjackson@xxxxxxxxxxxx; dromasca@xxxxxxxxx;
>>>don.alderrou@xxxxxxxxx; arnoldb@xxxxxxxxx; fkaudel@xxxxxxxxxxxxxx;
>>>David_Law@xxxxxxxxxxxx; robert.muir@xxxxxxxxx;
>>>bob.barrett@xxxxxxxxxxxxxxxxxx; hkaplan@xxxxxxxxx
>>>Subject: Re: [EFM-OAM] New update on EFM OAM Work Item #3
>>>
>>>
>>>
>>>
>>>Hugh, Vipul,
>>>
>>>Is there information at that layer in the OLT to know when
>>>data is coming from a particular ONU? This would be necessary
>>>to keep separate counters. If this is the case, what is the
>>>purpose of the LLID? If the physical layer knows which ONU
>>>is providing the information, doesn't the MAC layer also know?
>>>
>>>Regards,
>>>Ben
>>>
>>>Hugh Barrass wrote:
>>>
>>>>Vipul,
>>>>
>>>>I hate to say this, but the complex option may be required:
>>>>
>>>>If we assume that the FEC is implemented, it will be
>>>
>>>important to have FEC
>>>
>>>>corrected (and uncorrected) error counts at the OLT for
>>>
>>>each ONU. This will
>>>
>>>>allow an operator to debug problems with ONU lasers or
>>>
>>>fiber - either common or
>>>
>>>>separate sections.
>>>>
>>>>I think this will map to the virtual point-to-point concept.
>>>>
>>>>Hugh.
>>>>
>>>>Vipul Bhatt wrote:
>>>>
>>>>
>>>>>Ben,
>>>>>
>>>>>Perhaps you or others have thought about this, and
>>>>
>>>can comment.
>>>
>>>>>In a PON (1000BASE-PX), the medium is shared. The
>>>>
>>>link quality may
>>>
>>>>>differ from ONU to ONU, but the OLT receiver will be
>>>>
>>>common. So will
>>>
>>>>>we need multiple counters per OLT PMD?
>>>>>
>>>>>If yes, then it will be tricky to implement such
>>>>
>>>counters because
>>>
>>>>>each "link" is established only for a few
>>>>
>>>microseconds.  If not,
>>>
>>>>>then it raises a question of how useful such an
>>>>
>>>overall counter is.
>>>
>>>>>I agree it is better than nothing.
>>>>>
>>>>>Also, I wonder if it is appropriate to call the
>>>>
>>>1000BASE-X proposed
>>>
>>>>>counter as "coding violation counter" if we adopt an
>>>>
>>>FEC option.
>>>
>>>>>(Maybe it is a legitimate black box view - the
>>>>
>>>PMD/PMA will see an
>>>
>>>>>error rate of 10^-4, the FEC will clean it up to
>>>>
>>>10^-12, and then
>>>
>>>>>whichever bit it misses to correct will lead to, by
>>>>
>>>definition, a
>>>
>>>>>code violation error.)
>>>>>
>>>>>And finally, if we do insert an FEC sublayer below
>>>>
>>>PCS, we will be
>>>
>>>>>one level removed from the original intention behind
>>>>
>>>counting code
>>>
>>>>>violation errors - to monitor the health of the
>>>>
>>>optical link. If we
>>>
>>>>>want to monitor the status of an optical link, we may
>>>>
>>>need another
>>>
>>>>>counter that reports errors at the FEC-PMA interface.
>>>>
>>>Updating this
>>>
>>>>>counter can be the responsibility of the (optional) FEC
>>>>>implementation.
>>>>>
>>>>>Regards,
>>>>>Vipul
>>>>>
>>>>>===================
>>>>>
>>>>>
>>>>>>-----Original Message-----
>>>>>>From: owner-stds-802-3-efm-oam@majordomo.ieee.org
>>>>>>[mailto:owner-stds-802-3-efm-oam@majordomo.ieee.org]On
>>>>>>Behalf Of Ben
>>>>>>Brown
>>>>>>Sent: Monday, July 22, 2002 1:04 PM
>>>>>>To: Kevin Daines
>>>>>>Cc: stds-802-3-efm-oam@ieee.org; ambraga@iol.unh.edu;
>>>>>>tjackson@xxxxxxxxxxxx; dromasca@xxxxxxxxx;
>>>>>
>>>don.alderrou@xxxxxxxxx;
>>>
>>>>>>arnoldb@xxxxxxxxx; fkaudel@xxxxxxxxxxxxxx;
>>>>>
>>>David_Law@xxxxxxxxxxxx;
>>>
>>>>>>robert.muir@xxxxxxxxx; bob.barrett@xxxxxxxxxxxxxxxxxx;
>>>>>>hkaplan@xxxxxxxxx
>>>>>>Subject: [EFM-OAM] New update on EFM OAM Work Item #3
>>>>>>
>>>>>>
>>>>>>
>>>>>>All,
>>>>>>
>>>>>>Attached is an updated presentation regarding work
>>>>>
>>>item #3. Please
>>>
>>>>>>review and provide comments.
>>>>>>
>>>>>>David,
>>>>>>
>>>>>>Let me know what I need to do for the MAU attribute
>>>>>
>>>that you said
>>>
>>>>>>we need.
>>>>>>
>>>>>>Regards,
>>>>>>Ben
>>>>>>
>>>>>>--
>>>>>>-----------------------------------------
>>>>>>Benjamin Brown
>>>>>>AMCC
>>>>>>2 Commerce Park West
>>>>>>Suite 104
>>>>>>Bedford NH 03110
>>>>>>603-641-9837 - Work
>>>>>>603-491-0296 - Cell
>>>>>>603-626-7455 - Fax
>>>>>>603-798-4115 - Home Office
>>>>>>bbrown@xxxxxxxx
>>>>>>-----------------------------------------
>>>>>
>>>
>>>--
>>>-----------------------------------------
>>>Benjamin Brown
>>>AMCC
>>>2 Commerce Park West
>>>Suite 104
>>>Bedford NH 03110
>>>603-641-9837 - Work
>>>603-491-0296 - Cell
>>>603-626-7455 - Fax
>>>603-798-4115 - Home Office
>>>bbrown@xxxxxxxx
>>>-----------------------------------------
>>
> 
>