Re: MIPv6 hopeless

[Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp>]

Marcelo;

As I presented at Vienna, there is certain relationship between
mobility and multihoming, because both handles multiple
addresses, but the relationship is less than expected.

> 1- Inform host2 that an alternative address is to be used to continue
> with the communication. This is what BU message is for in mobility, so
> it seems reasonable that it is suitable for this task)

And security is the issue.

> 2- A mechanism to enable the end of the communication to identify
> packets with alternative addresses as belonging to the initial
> communication (this is what the Type 2 Routing header and Home address
> option is used for in mobility, so again they are good candidates)

Routing header is a waste of bytes and a possible cause of
MTU reduction problem.

> Clearly, you need to build alternative triggering mechanism. I mean, in
> mobility, BUs are triggered by movement detection mechanism. In this
> case you are not moving so this is not useful. What is needed is a
> failure detection mechanism that is the one that will trigger the BUs.
> This mechanism is not provided by MIP. Important benefits are achieved
> if this mechanism does not impose modification in host2 

A properly designed mobility protocol should support multiple
home agents at multiple locations.

But, the feature is missing in MIPv6. Note that an MIPv6 feature
of having multiple home agents at a single subnet is nothing more
than a useless complication.

So, there is nothing to be reused and we should define a packet
format to support site multihoming, which can be reused to
support multiple home agents at multiple subnets.

> > Ones between MN and CN? How is the security, then?

> This is the difficult part, i guess.
> 
> MIP security is based in the RR procedure,

MIP security is based on shared secret shared between mobile hosts
and home agents.

							Masataka Ohta