Re: Requirements for IP Multihoming Architectures

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

Ben;

>    Additionally, during failure events described above, multihoming
>    solutions must provide re-routing transparency for applications;
                            ^^^^^^^^^^
>    i.e. exchange of data between devices on the multi-homed network and
>    devices elsewhere on the Internet may proceed with no greater
>    interruption than transient packet loss during the re-routing event.

You assume multihoming redundancy MUST be provided by re-routing.

That is a wrong assumption.

The requirement is that exchange of data between devices on the
multi-homed network and devices elsewhere on the Internet should
proceed with no greater interruption than applications can tolerate.

Tolerance varies application by application and applications do not
want routing protocols define the tolerance.

To let the applications control the tolerance, applications can not
be transparent to multihoming mechanism.

You may think that

>    with no greater
>    interruption than transient packet loss during the re-routing event.

is best possible. But, it is best possible merely among routing
based approaches.

Real world applications (not likely on the Internet yet) sometimes
use multiple independent pathes to carry the same data that there is
no interruption even if one of the path failes.

							Masataka Ohta