From: Jun Sun (jsun_at_junsun.net)
Date: 2002-08-21 21:58:58 UTC
On Sat, Aug 17, 2002 at 06:31:42PM +0200, Jacques Caron wrote:
> At 22:38 16/08/2002, Jun Sun wrote:
> >If I understand it correctly, Mobile IP requires a home base server,
> >while L2 uses vlan. It seems to me L2 approach should be faster,
> >because it only needs to broadcast a message so that switch can
> >update its table, while in the case of mobile IP there should a
> >series of actions (obtaining new IP for mobile client, mobile
> >client sending packets back to home base server, etc)
>
> If you exclude AAA, yes, the L2 approach should be faster. But moving to
> another AP should imply some AAA (if you use 802.1X to authenticate
> access), which is not necessarily shorter in number of roundtrips...
That is true, although pre-authentication should help quite a bit for this.
> Note
> that in the case of Mobile IP, the IP of the mobile node does not change
> (it's the whole purpose of Mobile IP), but indeed one has to communicate to
> the Home Agent the new location of the mobile node.
>
While the fixed IP address does not change, the second IP address (care-of address) does change whenever mobile client changes its attachment.
Of course, mobile IP offers greater benefit, as it allows one to travel across networks (I think) while vlan only works within the network.
Jun