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I do agree in applications that you have a gearbox in the module adding the
EDC to the host adds extra power and with little benefits for these ports.
But assuming IEEE defines a PMA service interface XLAUI /CAUI as proposed by
then EDC or retimer will be associated to an specific PMD without burdening
all PMDs or adding complexity to the ASIC.
SFP+ is a great example we can follow and according to Ovum-RHK:will grow through
2011 at 202% CAGR for good reasons and you can listen to the webcast
SFP+ defines both limiting and linear interface. A limiting port can only support SR and LR,
where a linear port can support SR, LR, LRM, and copper 10GSFP+Cu. For nx10G PMD interface
we should follow the SFP+ winning model! 8.5Gig FC is also based on the same model but
but with relax transmitter and a simple EDC for linear ports.
John Jaeger wrote:
email@example.com" type="cite">"Previously when I stated the OM3 link can be extended to 300 m and with increase link margin, the reply was there is no such application requirements." - not sure that is the way I remember the discussion going Ali. For me anyways, it was centered on questioning the incremental power & complexity/cost related to the required EDC for this optical PHY in order to obtain the longer reach. And yes, there were a wide range of expressed opinions on the application value of picking up some of the distribution tails, but I never heard such a definitive statement of 'no application requirement'. John -----Original Message----- From: Ali Ghiasi [mailto:aghiasi@BROADCOM.COM] Sent: Friday, March 14, 2008 3:41 PM To: STDS-802-3-HSSG@LISTSERV.IEEE.ORG Subject: Re: [802.3BA] Longer OM3 Reach Objective Jonathan In Jan 08 interim meeting I presented the following presentation http://www.ieee802.org/3/ba/public/jan08/ghiasi_02_0108.pdf and published in IEEE communication magazine: http://dl.comsoc.org/cocoon/comsoc/servlets/GetPerson?id=10033162 which showed even with a 4G transmitter a 300 m OM3 link has one dB more margin using a simple EDC (Electronic Dispersion Compensation) compare to a limiting link operating over 100 m of OM3 fiber, similar to: http://www.ieee802.org/3/ba/public/mar08/pepeljugoski_01_0308.pdf. To meet IEEE objective to support copper cable for 10 operation, some form of EDC would be required. As long as the copper and the optical specifications for linear interface are not defined in orthogonal fashion, a port supporting copper cable can greatly benefit a port supporting linear optics and extend the reach to 300 m! Previously when I stated the OM3 link can be extended to 300 m and with increase link margin, the reply was there is no such application requirements. It is good to hear from people like you. Thanks, Ali Jonathan Jew wrote:I am a consultant with over 25 years experience in data center infrastructure design and data center relocations including in excess of50data centers totaling 2 million+ sq ft. I am currently engaged in data center projects for one of the two top credit card processing firms andoneof the two top computer manufacturers. I'm concerned about the 100m OM3 reach objective, as it does not cover an adequate number (>95%) of backbone (access-to-distribution and distribution-to-core switch) channels for most of my clients' datacenters.Based on a review of my current and past projects, I expect that a 150m or larger reach objective would be more suitable. It appears that some ofthedata presented by others to the task force, such as Alan Flatman's Data Centre Link Survey supports my impression. There is a pretty strong correlation between the size of my clients' data centers and the early adoption of new technologies such as higher speedLANconnectivity. It also stands to reason that larger data centers have higher bandwidth needs, particularly at the network core. I strongly encourage you to consider a longer OM3 reach objective than100m.Jonathan Jew President J&M Consultants, Inc firstname.lastname@example.org co-chair BICSI data center standards committee vice-chair TIA TR-42.6 telecom administration subcommittee vice-chair TIA TR-42.1.1 data center working group (during development of TIA-942) USTAG representative to ISO/IEC JTC 1 SC25 WG3 data center standard adhoc
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