From: Frank Bulk (no email)
Date: Mon Jan 21 2008 - 20:07:42 EST
Your points about the marketing and usage value of higher asymmetric is
right on. Not only are the higher numbers attractive, they generally
reflect a residential subscriber's usage pattern (there are some on this
listserv who have pointed out that those with very high symmetrical speeds,
100 Mbps, for example, do have higher upstream, but I think that's because
they are more attractive P2P nodes) and so residential broadband networks
have been designed for asymmetric service. One of the reasons that business
broadband is more expensive is that they not only use their 'pipe' more
heavily than a typical user provisioned with the same speeds (i.e. bandwidth
costs are more), they also prefer a symmetrical connection for their e-mail
server and web traffic which requires different (lower volume and more
expensive) equipment and/or they consume more of that shared upstream link.
BPON/GPON is also asymmetric, as you point out, but because the marketed
highest-end speeds are a fraction of the standards' capabilities, the
asymmetry and potential oversubscription are easily overlooked. This works
to Verizon FiOS' advantage while marketing its symmetrical plans.
I personally prefer Active Ethernet-based fiber solutions for the reasons
you allude to -- they more closely match enterprise network architectures
(that's why we see Cisco in this space (i.e. Amsterdam's fiber network) and
so networks of this type can leverage that equipment, volumes, and pricing):
symmetrical in speed and switched. The challenge with the Active Ethernet
architecture is that most often active electronics need to be placed in the
field, while many PON solutions can use passive optical splitters.
Frank
-----Original Message-----
From: Sean Donelan [mailto:]
Sent: Monday, January 21, 2008 4:47 PM
To: Frank Bulk
Cc:
Subject: RE: An Attempt at Economically Rational Pricing: Time Warner Trial
On Mon, 21 Jan 2008, Frank Bulk wrote:
> You're right, the major cost isn't the bandwidth (at least the in the
U.S.),
> but the current technologies (cable modem, DSL, and wireless) are
thoroughly
> asymmetric, and high upstreams kill the performance of the first and
third.
There are symmetric versions for all of those. But ever since the dialup
days (e.g. 56Kbps modems had slower reverse direction) consumers have
shown a preference for a bigger number on the box, even if it meant giving
up bandwidth in the one direction.
For example, how many people want SDSL at 1.5Mbps symmetric versus ADSL at
6Mbps/768Kbps. The advertisment with the bigger number wins the consumer.
I expect the same thing would happen with 100Mbps symmetric versus
400Mbps/75Mbps asymmetric. Consumers would choose 400Mbps over 100Mbps.
> Long-term, fiber avoids the upstream performance issues.
Asymmetric fiber technologiges exists too, and like other technologies
gives you much more bandwidth than symmetric fiber (in one direction).
The problem for wireless and cable (and probably PON) is using shared
access bandwidth. Sharing the access bandwidth lets you advertise much
bigger numbers than using dedicated access bandwidth; as long as everyone
doesn't use it. The advantage of dedicated access technologies like
active fiber (or old fashion T-1, T-3) is your neighbor's bad antics
don't affect your bandwidth.
Remember the good old days of thicknet Ethernet and what happened when
a single transceiver went crazy, the 10Mbps ethernet coax slowed to a
crawl for everything connected to it. The token ring folks may have
been technically correct, but they lost that battle.
There was a reason why IT people replaced shared thicknet/thinnet coax
Ethernet with dedicated 10Base-T pairs and switches replaced hubs.
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