wireless support of roaming between subnets ?

[Marco Molteni]

Hi Juan,

On Thu, 6 May 2004 Juan Rodriguez Hervella <jrh at it.uc3m.es> wrote:

> Hello,
> 
> I'd like to try on some changes that I've made in our VoIP
> testbed for mobility support at the application layer.
> 
> If the user requires support for seamless voice communication during
> active call sessions on the mobile UA, it is imperative that the
> wireless LAN setup should support roaming across subnets, i.e. the
> mobile host should obtain a different IP address if it reassociates
> itself with an Access Point (AP) in a different subnet.

I don't understand...

If you want to keep your session at a layer above IP, you must
*not* change IP address when you roam. You can achieve this with
Mobile IP. I don't know about MIPv4, but MIPv6 is supported by
KAME (http://www.kame.net/)

I would suggest trying the KAME mailing list.

Regarding seamless handover and similar stuff, you should check the
various IETF working groups, like
MIPv6 Signaling and Handoff Optimization (mipshop)
http://www.ietf.org/html.charters/mipshop-charter.html

Otherwise, if you really want to do what you stated:

> the mobile host should obtain a different IP address

you are already all set for this: when the 802.11 card associates,
you trigger a DHCP request to get a new address.

Have also a look at the following thread:
http://docs.FreeBSD.org/cgi/mid.cgi?39FE23FA-7F75-11D8-8F99-000A95CDA38A

[..]

> Where is it coded the wireless support on FreeBSD ? I'd like
> to use FreeBSD-4.9 if that is possible....Besides, do I need to 
> try to apply the previous patch to support roaming ? Any
> pointer or suggestion will be useful, of course.

the patch you are referring to is for linux, so you cannot apply it
to fbsd ;-)

wireless support in fbsd uses a new unified framework called "wlan", start
with "man wlan" on a freebsd-current machine, or look at
http://www.freebsd.org/cgi/man.cgi

source is at
/usr/src/sys/net80211/

Don't know about 4-stable.

marco