Query below:
Gervas
--- In [email protected], Gregg Wonderly
<[EMAIL PROTECTED]> wrote:
>
> Mark Baker wrote:
> > On 5/26/06, Gregg Wonderly <[EMAIL PROTECTED]> wrote:
> > > When I
> > > asked "Do I really care about which protocol", I really wanted
to say "should I
> > > compromise my design to take advantage of a particular protocol".
> >
> > I can see that you're still having trouble getting past the whole
> > "'protocol' == low level" thing. Data formats are protocols too; is it
> > bad for a system to pick one/some of those? Of course not. For all
> > systems, you have to pick protocols, preferably ones which are already
> > well deployed by the audience for that system, because to do otherwise
> > is to reduce the number of people able to use it. Whether that's
> > transport, transfer, or data format, picking one isn't bad, it's a
> > necessary for interoperation.
>
> Perhaps you are not familar with the history of the telephone
network? The
> problem with the telephone network is that it was design to only use
realtime,
> synchronous transports such as X.25, X.75, ATM etc. When the
internet came into
> view, there was no equipment which could effectively provide this
translation
> from synchronous to the asynchrony of the internet. All the
hardware, software
> and systems involved in the network couldn't be reinterfaced to a
new world
> without massive reengineering. This is why VOIP is taking that
industry by
> storm. They depended on a transport technology at an extremely low
level and it
> was ingrained into every possible piece of these systems. No chance
for
> adaptation and any reasonable cost.
Could you please clarify what you mean by the preceding paragraph?
Traditional TDM telecoms networks (PDH, SONET, SDH etc.) can be used
for transporting all manner of data/packet-based protocols including
connectionless and asynchronous protocols. Although you can have a
pure ATM network (Asynchronous Transfer Mode by definition is
difficult to classify as synchronous even though Stratacom tried to
implement it as such), you are more likely to transport it over
SDH/SONET. Likewise with many IP networks including Internet connections. IP, being a connectionless Layer 3 (in the still-useful OSI Reference Model) Network Protocol can be transported over practically any Layer 2/1 combination, including ATM, X.25, dial-up, etc.
It is only since very recently that carriers are looking to implement
pure wall-to-wall IP networks without an SDH/SONET substrate.
>
> > > I.e. as soon
> > > as I am dependent on transport/transfer, I've introduced the
9th fallacy,
> > > "Everyone speaks the same transport/transfer protocol as is
hard coded in the
> > > application."
> >
> > How is that a fallacy exactly? And how can agreement on
> > ever-increasing layers of a stack be bad?
>
> The description above is one illustration. Another example is web
browsers.
> Todate, I've yet to see one that supports "tcp:<portno>". Thus, we
have to
> write servlets or CGIs to provide simple web services. Why is that?
What if I
> just want to send a simple document. Why do I have to have a web
server to do that?
>
> The use of a higher layer protocol has caused that to be a
dependency that we
> can't get past. One has to use HTTP for firewall bridging just
because that's
> viewed as a safe port to open. In reality, it's no safer than any
other
> arbitrary TCP port unless you've actually nailed down the entire
network, in
> both directions, for all possible addresses. Somehow people feel
like HTTP is
> safe, yet it continues to be a most common path of exploitation
because it
> allows arbitrary content through. Believe me, I greatly enjoy what
I can do
> with my we browser to use information and services on the web. But,
I don't
> find it an attractive form of "dependable" and "secure" service.
>
> Gregg Wonderly
>
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