We need to
resend in 30 seconds, perhaps, and if mumble time units elapse
without successful delivery we need to initiate a response to the
sender indicating that s/he should try another communication channel
while we continue to retry this one.
Waiting 30 seconds would be unwise in the scenario described.
Instead of waiting, the sending application should be sending
2 or 3 copies of the message via different routes to ensure
that it gets there as quickly as possible.
For existing models on how to accomplish this in IP, you
should look at the financial services industry where tickers
and other market datafeeds must get to the recipient as fast
as possible because millions of dollars are at stake. In this
environment, datafeeds are sent via multicast. Each packet is
duplicated and sent via two different multicast trees which
travel over infrastructure which is entirel discontiguous,
i.e. separacy is enforced right down to the physical layer.
It works well and something like this is likely to be the
right way to handle critical emergency communications. Note
that an important aspect of this type of solution is that it
defeats IP routing's concept of the single best path for a packet.
This means that if you don't need the multiple recipients that
a market data feed requires, you might find a way to do something
similar with MPLS TE that is more suited to emergency comms.
Those experts aren't in the ITU, and the ITU at this point doesn't
have the expertise to even say what was said in my long paragraph
above.
And the ITU does not have applications layer experts which
is what you need to design a communications solution for some
very specific and very important applications layer requirements.
Some people are assuming that lower level protocols need to
be *fixed* to enable this but I do not agree that is the case.
I do believe that having a requirements-generating working group is a
good thing.
Yes. And get some other applications domain experts to contribute
such as people from the financial industry or SIAC. IMHO, the
financial industry treats this matter with much greater care
and importance than the defense and security sector because in
the financial services industry, the impact of communications
failures is immediate and can be severe. Unlike the defense and
security sector who must deal with events sporadically, in financial
services the events are numbered in transactions per second.
--Michael Dillon
_______________________________________________
Ietf mailing list
Ietf(_at_)ietf(_dot_)org
https://www1.ietf.org/mailman/listinfo/ietf