Subject: [core] draft-ietf-core-coap-06 Critical / Elective options and proxies

From: Cullen Jennings <[email-masked]>
Date: Wed, 4 May 2011 20:50:16 -0600

Saying that proxies have to understand and process all critical options is going to make it very difficult to get anyone to agree to deploy new options. The problem is the endpoints won't use new critical options because they won't work because the proxies does implement them and the proxies won't implement them because no end points use them. (yes, I'm a huge fan of Handley's internet only just works paper. My suggestion would be to have three classes, elective, critical, and proxy critical. Proxy critical means it is critical for proxies and end points.

The proxy would forward elective and critical requests regardless of it the proxy understood them or not while proxy critical options that were not understood would result in an error.  I might suggest the rule for determining if an option was proxy critical or not might be that for option numbers greater than 16, if the option number mod 8 was 7, then it was proxy critical. Or some rule along these lines and just special case the options numbers already in use. 

Cullen <in my role as an individual contributor>