Subject: Re: [Simple] SIMPLE and Emergency Services

From: Bernard Aboba <[email-masked]>
Date: Wed, 31 Oct 2012 15:08:29 -0700

In response to Olle's question about whether SIMPLE is an abject and irredeemable failure,  I would note that SIMPLE is still under consideration for use in emergency services, if only because XMPP isn't yet a viable alternative.  For example, both NENA i3 and ECRIT PhoneBCP mention SIMPLE, but refer to XMPP support of emergency services as future work.  In emergency scenarios, presence and address books are typically not considered since the PSAP is neither a presentity nor a watcher.   Instead, SIMPLE is used as a way of conveying information between the caller and PSAP, including location, a message body and additional data. With SMS to 911 under active discussion with regulatory bodies, the question about whether we can rely on SIMPLE for emergency use has become a "hot issue".   As an example, there has been a suggestion that MESSAGE could be used to  support conveyance of SMS text messages to a "text gateway"  that would then pass them on to the PSAP (possibly in a different form, such as translating to TTY/TDD).  Not only might this help standardize the transport of SMS messages to 911, but it would also support future uses of MESSAGE for next generation emergency services. 
While documents like NENAi3 and ECRIT PhoneBCP still point to SIMPLE specs, some folks have pointed to the lack of support for MESSAGE in SIP trunking services as an indication that even basic uses of SIMPLE are unlikely to see much deployment, and that alternatives for disabled access to emergency services (such as RFC 4103 realtime text) should be given priority. 
IMHO,  unless XMPP for emergency uses is specified by IETF in the near future, it is likely that SIMPLE will find its way into emergency services architectures in some form.  Since the IETF is still recommending SIMPLE in documents such as ECRIT PhoneBCP, IMHO the IETF has a responsibility to public safety to address interop issues that will arise in next generation emergency services scenarios.  AFAIK, SIMPLE interop issues haven't killed anyone yet.  Hopefully this will remain true in the future.  
Olle E. Johansson said: "Any other thoughts in regards to SIMPLE?

Is it a failure or not?

Do we have a chance of fixing this within the IETF?

Is anyone interested in fixing it so we actually reach the WG goal of interoperability?"