RE: Issues concerning 10GbE speed standards

[Fred Weniger <weniger@vitesse.com>]

All,

Could one deduce from this discussion that FEC, which lowers BER at the
expense of requiring up to 25% higher bandwidth, is therefore a bad thing?
And, if it's a bad thing, are any of you advocating that therefore, FEC
should not be employed on existing SONET rings?





At 09:20 AM 6/26/99 -0700, Paul Bottorff wrote:
>
>Drew:
>
>The data I've seen agrees exactly with your outlook that the total system
>cost is considerably higher using 12.5 Gig rather than 10 Gig. In addition,
>the installed base of transmission systems, which has many available
>lambda, is definitely 10 Gig. The 12.5 Gig solutions can only be used in
>for new installations.
>
>Our current research indicates that the scrambled encoders do not increase
>the cost of components versus 8b/10b when used for the same application.
>Infact, we believe scramblers are less costly than 8b/10b due to the lower
>frequencies. The current analysis of 8b/10b considers the effects of jitter
>compared to the worst case conditions for scrambled coding. This analysis
>does not give an accurate picture of the requirements for scrambled
>encoding since the probability of the imbalance used in the comparison is
>once  in more than 10,000 years. Scramblers are statically DC balanced, it
>is necessary to look at the requirements statistically rather than in the
>worst case.
>
>Paul
>
>At 10:21 PM 6/25/99 -0700, Drew Perkins wrote:
>>
>>Peter and Roy,
>>	The cost of higher speed in the WAN is not so much that of the
>>electronic parts, but rather the fact that you need more of them for long
>>distances. This is because most optical effects such as dispersion increase
>>with the square of the distance. Thus increasing the speed by 25% increases
>>the optical effects by 56%, and that tends to decrease the distance you can
>>go by  about a third. Then you need 33% more spans to go the same distance.
>>Also, in order to send 25% more bits, you wind up increasing the power by
>>25%, and you use more optical bandwidth. And since you are sending more
>>bits, you are using more optical bandwidth. These facts result in fewer
>>optical channels being supportable on a fiber, resulting in more fibers
>>being used, resulting in more line systems, etc.  The result again is more
>>equipment and higher costs.
>>
>>Actually, the electronic parts might become less expensive with the 25%
>>extra speed. The balanced nature of the 8B10B code decreases the cost and
>>attention that must be paid to jitter.
>>
>>Drew
>>---------------------------------------------------------
>>Ciena Corporation                 Email: ddp@lightera.com
>>Core Switching Division                 Tel: 408-865-6202
>>10201 Bubb Road                         Fax: 408-865-6291
>>Cupertino, CA 95014              Cell/Pager: 408-829-8298
>>
>>
>>-----Original Message-----
>>From: owner-stds-802-3-hssg@majordomo.ieee.org
>>[mailto:owner-stds-802-3-hssg@majordomo.ieee.org]On Behalf Of
>>Peter_Wang@3com.com
>>Sent: Friday, June 25, 1999 8:35 PM
>>To: rabynum@airmail.net
>>Cc: stds-802-3-hssg@ieee.org
>>Subject: Re: Issues concerning 10GbE speed standards
>>
>>
>>
>>
>>
>>Roy,
>>
>>>From a number of the component vendors' presentations at CFI, I don't
recall
>>anyone claiming that the cost of the electronic parts (SiGe or GaAs) will be
>>much different between 10 & 12.5 Gbps.  The primary cost issue seemed that
>>of
>>the relative laser performance (e.g. temperature stablization).  Also, if
>>you
>>are talking about "converting" an existing Sonet chip to silicon (meaning
>>that
>>the existing desing is in GaAs) and throwing away a bunch of circuits, I
>>wouldn't be so sure that the development cost would be much less.  In any
>>case,
>>assuming the volume is large (which I'm sure everyone's hoping), the
>>development
>>cost will be amortized, and hence not a significant factor.  But this is a
>>discussion for LAN (or enterprise) applications.  I was trying to understand
>>the
>>economics of applying Ethernet to WAN but forcing it within the existing WAN
>>practice, and hoping you could provide some insight.
>>
>>Peter
>>
>>
>>
>>
>>Roy Bynum <rabynum@airmail.net> on 06/25/99 04:50:23 PM
>>
>>Please respond to rabynum@airmail.net
>>
>>Sent by:  Roy Bynum <rabynum@airmail.net>
>>
>>
>>To:   Peter Wang/HQ/3Com
>>cc:   stds-802-3-hssg@ieee.org
>>Subject:  Re: Issues concerning 10GbE speed standards
>>
>>
>>
>>
>>
>>Peter,
>>
>>Just because a SONET OC192C framing is used, does not mean that the OAMP
>>functionality is active in the LAN interface.  If OAMP processing is not
>>needed, only the existing SONET chip set, converted to silicon, with
>>most active functionality, other than path BER can be disabled.  This
>>will leverage the existing technology without the higher cost of the
>>APS, line and section overhead, etc.
>>
>>Having worked on devices before, I know that the higher the bit signal
>>rate the more expensive the devices.  With a PHY that is 1/4 higher in
>>bit rate, compared the 8B/10B signal rate, the OC192 rate may be less
>>expensive.
>>
>>Roy
>>
>>
>>
>>Peter_Wang@3com.com wrote:
>>>
>>> It will help a great deal if you could point out specific aspects and
>>approaches
>>> where an Ethernet extended to support all of the existing common carrier
>>O&M
>>> requirements, encapsulated within the existing Sonet/SDH structure,
>>running
>>over
>>> existing OC192/STM64 facilities, will actually come out costing
>>significantly
>>> less that the current solution?
>>> - Peter
>>>
>>> Roy Bynum <rabynum@airmail.net> on 06/20/99 07:34:08 AM
>>>
>>> Please respond to rabynum@airmail.net
>>>
>>> Sent by:  Roy Bynum <rabynum@airmail.net>
>>>
>>> To:   wthirion@level1.com
>>> cc:   stds-802-3-hssg@ieee.org, stds-802-3-hssg-speed@ieee.org (Peter
>>>       Wang/HQ/3Com)
>>> Subject:  Issues concerning 10GbE speed standards
>>>
>>> Walt, et al,
>>>
>>> The issue of speed is one of economics.  The existing GbE standard does
>>> not allow for any operations support for the optical fiber facility.
>>> This makes GbE very expensive to maintain and support over a MAN/WAN
>>> environment.  The cost of ownership of GbE will prevent it from having a
>>> masive impact directly on the cost of MAN and WAN data communications.
>>>
>>> Common carrier protocols, such as DS1/DS3/SONET/SDH have operations and
>>> maintencance functionality incorporated in the overhead of the
>>> protocol.  DS1 and DS3 have a subcarrier that provides remote and
>>> reverse signalling outside of the transport "payload".  This allows
>>> carriers to troubleshoot and maintain remote systems without haveing to
>>> dispatch someone for every little issue.  In some respects, GbE fails to
>>> meet the 802.3 functional requirements for interoperation with common
>>> carrier systems.
>>>
>>> 1000BaseSX and 1000BaseLX are optical networking standards.  Whether
>>> this was the intention or even the perception of the 802.3 working
>>> group.  The working group did not include any support for operations or
>>> maintenance in the optical domain for this protocol.  The functional
>>> operations of copper LAN facilities are well understood by the 802.3
>>> working group, but when you get beyond multi-mode, 850nm, optical
>>> transport, it is no longer a LAN, it is a WAN.  Some will say that 30km
>>> is a MAN, not a WAN.  If you apply the same function processes
>>> distictions to optical systems that are applied to copper systems, you
>>> will discover that a MAN is actually a WAN within a single central
>>> office domain. When I was actively working on Ethernet, when it left the
>>> building, it was no longer a LAN, it was a WAN.
>>>
>>> In order for 10000BaseX to support MAN/WAN systems within common carrier
>>> facilities, common carrier operations and maintance support must be
>>> within the protocol.  SONET/SDH are the current, and most widely
>>> deployed transport protocols within the common carrier domain.
>>> SONET/SDH use the transport overhead to provide that functionality.
>>> That functionality allows the common carriers to reduce the operations
>>> and support costs for the fiber optic transport systems, and thus lower
>>> the overall costs passed on to the end users.  This will be the economic
>>> breaking point for 10GbE.  Can it directly support the fiber optic
>>> transmission system?  Is there any reason why it should not be able to
>>> directly provide operations support for the optical fiber systems?
>>>
>>> A second economic issue of speed for 10GbE is one of utilizing existing
>>> technology and standards at the ~10Gigabit speed range.  A masive
>>> install base of facilities and support already exist for OC192/STM64 on
>>> a global scale.  Optical amplifers, signal and clock recovery
>>> regenerators, and other systems are already in place to carry
>>> OC192/STM64 signals in metropolitan as well as wide are networks.  I
>>> would not want to contemplate the economic impact of having to install
>>> totally seperate technology to support 10GbE.  If it can not use the
>>> existing ~10Gb technology and facilities, Other than "dark fiber", 10GbE
>>> will have to be installed over a totaly new, and totaly seperate
>>> facilities.  Is there any reason why 10GbE should not support and make
>>> use of the existing ~10Gb transport facilities?
>>>
>>> I hope that this message has not been too long.  As an employee of a
>>> common carrier company, I have a recognizable vested interest in looking
>>> toward 10GbE as a major economical alternative to existing data tranport
>>> technolgy, such as TDM or ATM.  I have almost 20 years of designing,
>>> installing, and supporting LAN, MAN, and WAN systems.  I have seen the
>>> economics change as more self-supporting protocols and technologies have
>>> become available.  The key is to provide a protocol that allows remote
>>> operations support, which reduces the number of "warm bodies" that are
>>> required to support the systems.  This is what I am asking for.  Is
>>> there any reason why this can not be done?
>>>
>>>                          Thank you,
>>>                          Roy Bynum
>>>                          MCI WorldCom
>>
>>
>>
>>
>>
>>
>Paul A. Bottorff, Director Switching Architecture
>Bay Architecture Laboratory
>Nortel Networks, Inc.
>4401 Great America Parkway
>Santa Clara, CA 95052-8185
>Tel: 408 495 3365 Fax: 408 495 1299 ESN: 265 3365
>email: pbottorf@NortelNetworks.com
>


Fred Weniger
Product Marketing Manager, Gigabit Products
Vitesse Semiconductor Corporation
741 Calle Plano, Camarillo, CA 93012
Phone: 805-388-7571   Fax: 805-987-5896
E-mail: weniger@vitesse.com