mobile challenges

["tim clifford" <tjc@lacunanet.net>]

There are a few statements about the challenges of mobile networking that I
feel could use elaboration.

"The fundamental difference with fixed Internet access networks is that the
attachment point of end devices to the Internet changes as users of devices
are in motion "

"The requirements stem from
solving three problems associated with wireless access:
* mobile IP routeing - rapid handoff between access points
* fast registration and de-registration on handoff between disparate
technologies (micro v macro mobility)
* maintaining context and QoS in handoff"

I suggest these underestimate the challenge; all of the pieces are new from
the legacy internet perspective and each contributes to an engineering
tradeoff that make successful evolution of mobility a challenge. I suggest
we need a much broader and more rigorous explanation here, a few thoughts to
start
- device issues place a number of constraints on the protocols used to
create transfer; while I'm not necessarily a fan of WAP, I appreciate that
its designers tried to address screen size and link issues (among many
others)
- link characteristics create a number of technical issues along with
financial constraints
- the postulated size and always on characteristic of the user population
will affect scaling in various back end functionality
- mobility is mentioned above, but capabilities like roaming have little
precedent in an internet environment.

tim