Re: how mobile do we want to be

Iljitsch van Beijnum wrote:

> In the discussion in the BOF yesterday there were different viewpoints
> on the relationship between mobility and multihoming in general and
> shim6 in particular.
>
> Apparently, some people are equating renumbering with mobility. Now
> obviously mobility mechanisms can be used to renumber without skipping
> a beat, but that doesn't mean mobility and renumbering are the same
> thing.
>
> I think the important difference is the timescale. In mobility, the
> assumption is that TCP sessions and other state are longer-lived than
> locator addresses. In site renumbering, I very much doubt that this is
> the case. At the very least, we're talking about the order of days
> here, and _very_ few sessions or associations last for days.

I don't know what you call "_very_ few", but I can think of three
applications that I use daily which have long lived TCP connections...
often lasting days or more. These three are ssh (with tunneled apps), IM
(aol, yahoo), and mp3 streaming (as a listener). I probably wouldn't care
_too_ much if they broke occasionally due to renumbering and I had to
restart them, but if this behavior became frequent, then it would become
annoying. However, I can only speak for myself. There may be others (eg,
mp3 streaming servers) who would find it more than annoying if it happened
at all.

<snip>

> I think HBAs are a very good compromise between reasonable security and
> usability. It would be a shame to throw this out the window just so one
> or two applications are saved from reconnecting once in a blue moon.

How much demand for timeliness do you think is enough to justify
addressing it? In my opinion, I think the fact that there are _any_
demands for it now (mobility & my 3 example apps), is reason enough to
address timeliness. If timeliness isn't addressed, aren't we being
short-sighted with respect to future applications?

~armando

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| Armando L. Caro, Jr. |  Protocol Engineering Lab |
| www.armandocaro.net  |    University of Delaware |
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