[LINK] Next Gen Ethernet

[Glen Turner]

On Wed, 2007-07-25 at 06:55 +0000, stephen at melbpc.org.au wrote:

> Ethernet has sped up by a multiple of 10 several times, from 10Mbps to 
> 100Mbps and ultimately from 1Gbps to 10Gbps, the current fastest version. 
> Some HSSG members backed a similar boost this time and that 100Gbps plan 
> appeared to have won out late last year. But others pushed for a 40Gbps 
> standard. 

For those wondering why, this was the expected showdown between
the metro ethernet firms and the telco gear firms.  Those loving
a good technical catfight purchased ringside seats, us less
fortunate used the video streaming.

The metro ethernet firms won't be able to sell 40Gbps ethernet to
anyone. It's just not fast enough -- four 10GE links running in
parallel is almost as convenient and is much cheaper.  And there's
no certainty that the peering points like LINX, DeCIX and PAIX
will buy a 40G switch, since they are running near 100G now and
won't want to provision a 'new' ethernet that will already need
a three links in parallel. Similar considerations apply for
'campus' style networks, where 100G to a building is much
more desirable than 40G to a building at a slightly lower
price.

The telco gear firms need to sit ethernet inside a WDM framing
for long distance transmission. 40G fits nicely, 100G doesn't,
wasting 30% of the available space. Moreover, the top rate of
most long haul transmission equipment is 40G per wavelength. So
anything in excess of that needs multiple wavelengths. In which
case, you may as we deliver multiple 40G ethernet to the customer
and let them do the channel building.

Server builders currently side with the 40G telco gear manufacturers,
as it's just possible to build a 40G NIC, but not a 100G NIC yet.
When that changes, then they'll change allegiance. You see both
parties wooing the server people with copper interconnects.

The decision to build both ("let the market decide") is a poor
one. You'll notice that delivery date of 2010. That's a two year
slippage. Immediately following the meeting Cisco Systems announced
a non-standard interim 40G product and I expect Force10 to announce
a non-standard interim 100G product at some stage. They have no
choice, they have customers wanting to buy kit. But we saw with 100VG
AnyLAN just how annoying a widely used but not interoperable ethernet
can be.

Keeping the two speeds in one standard isn't to clever from a customer
point of view. That means that neither 40G nor 100G will be available
as a final standard product until the slower development finishes.
That's a tactical win for 40G, which would have a very hard time
should the 100G standard appear first.

> "I wouldn't say there was a fight. I would say there was an education 
> going on and it got heated at times," D'Ambrosia said.

Translation: there was no fight, because the showdown has been pushed
to some time in the future. Probably to when the first of the speeds
is finished.

The other showdown lurking in the background is the replacement
of 1500 bytes as a standard ethernet frame size with something
more reasonable at 100Gbps, like 64KB or 1500MB.

-- 
 Glen Turner