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Re: [HSSG] 40G MAC Rate Discussion


I can understand  availability of 4x10GBASE-KR silicon.  Are you using 
LAG on top of the 4x10G PHY or are
you using a proprietary 40G MAC?


Hugh Barrass wrote:
> Ali,
> There is silicon available today that can run 4 x 10GBASE-KR as an 
> aggregated link (4 x 10). It has the advantage that it can support 
> links to multiple edge devices or a 40G aggregated link between 
> redundant switch fabrics. A single 40G link would be the same cost and 
> would take the same real estate as the 4 x 10 links. If you invest to 
> make a new generation that can support a single 40G MAC the added 
> value will be minuscule, I don't see how you could recoup the 
> investment. On the other hand, it would be a similar investment to 
> develop the 100G MAC and such a device is more suitable as an uplink 
> for a switch fabric that is serving 16 x 10G blades. The 100G MAC, 
> along with the attached fabric will be used for the inter-switch links 
> and will be more immediately useful, a 40G single MAC would be 
> marginally more useful than the 4 x 10 you already have. I know where 
> I would bet my investment dollars...
> Hugh.
> Ali Ghiasi wrote:
>> Marcus and Others
>> I like to present another point of view in support of 40 Gig MAC.
>> We currently have the following option on the backplane side
>>    - KX-4 (XAUI) 10Gig
>>    - KR (1 lane ) 10Gig
>> The natural next step for backplane Ethernet will be to operate KX-4 
>> lanes at 10.3125 Gbaud.
>> Regardless of what decision we make in the HSSG 40Gig MAC will exist 
>> for the backplane.
>> Assuming we will define the 40Gig MAC sooner or later then allowing 
>> 40 Gig MAC
>> for front panel becomes even more compelling, specially when 100Gig 
>> is overkill for these
>> applications in near term.  If we define 40Gig MAC in the HSSG then 
>> defining 40Gig
>> backplane becomes travail.
>> applications.
>> Thanks,
>> Ali

fn:Ali Ghiasi
adr;dom:;;3151 Zanker Road;San Jose;CA;95014
title:Chief Architect