On Sun Feb 19 23:23:59 2006, Dave Crocker wrote:
Folks,
Eric said:
> 1. It is slower because it requires two handshakes.
> 2. The client may have to authenticate twice (this is a special
> case of (1)).
>
> The second case can be easily ameliorated by having the client
send an
> extension (empty UME?) in the first handshake as a signal that it
wants
> to do UMDL and that the server should hold off on demanding client
> authentication until the rehandshake happens.
>
> The performance issue is quite modest with modern servers.
Indeed, it's
> quite common for web servers to do a first handshake without
cert-based
> client auth and then rehandshake with client auth if the client
asks for
> a sensitive page.
This raised a flag with me. Within the Internet protocol context I
have always seen significant concern for reducing the number of
exchanges, because additional exchanges (hand-shakes) can -- and
often do -- have painful round-trip latencies. (Server capacity
can be a concern, of course, but not for this issue.)
Well, for those of us looking at Lemonade, etc, I think we're still
very concerned about every round-trip. Server capacity, too, is a
very real problem, and, while I admit to not having looked at this
specification yet, given what I've read thus far, I'm assuming this
has some applicability to email protocols as well as HTTP, which
would affect Lemonade.
For all of the massive improvements in the Internet's
infrastructure, my impression is that round-trip delays can still
be problematic.
Yes, I believe it has something to do with the difficulty of changing
the speed of light. Probably requires standards action on a bunch of
normative references, or there's a global upgrade problem.
Is it true that we no longer need to worry about regularly adding
extra round-trips to popular protocols that operate over the open
Internet?
No.
As far as I'm aware, there is no protocol in existence which
somebody, somewhere, does not actively use over a mobile phone link,
or a slow analogue modem, and this is especially true of TLS enabled
protocols such as HTTP, email protocols, etc.
Dave.
--
You see things; and you say "Why?"
But I dream things that never were; and I say "Why not?"
- George Bernard Shaw
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