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Re: IPSEC tunnels and Mobile IP

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Pat Calhoun wrote:

>I would prefer to call it portable, not mobile. I agree with you that
>the need for Mobility in early 1998 is limited, but I am convinced that
>this will change within the next 2 years as technologies such as GSM
>(among others) become ubiquitous. 

That's right, by this definition, mobile means "does not need to be
booted after moving from one place to another".

I think an important observation is that mobility could be handled
by different levels in the protocol stack. In the case of circuit
switched GSM, for instance, the GSM system has its own mechanisms
for handling mobility - the other end of a call is always attached
to your ISP's modem pool while your end moves around. While I think
that the GSM packet switched standards are not completely ready, I
believe that there are similar mechanisms in there as well. This makes
mobile IP only useful in cases where you switch between media (office
LAN to GSM). (I'm not a true GSM expert; it is possible that there
are also some exceptional cases such as moving from one country to
another which may not be supported by all versions of the underlying
mobile network mechanism.)

/Jari

P.S. I happen to live in a country where mobility already is ubiquitous:
in Finland 40% of _all_ people have a mobile phone :-)
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Jari Arkko, Oy L M Ericsson Ab, 02420 Jorvas, Finland. Tel +358 9 2992480
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WWW: http://www.iki.fi/jar. Standard disclaimers apply.
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