Subject: [6lo] Tim's INT DIR review for RFC6775 update: registration lifetime unit

From: "Pascal Thubert (pthubert)" <[email-masked]>
Date: Tue, 20 Feb 2018 13:10:18 +0000

Dear all :

As part of his review Tim asked "
The registration lifetime is in minutes; why not in seconds?
"
To which I answered that
"

> RFC 6775 is missing a way to express the time unit (RPL has one). 
We used minutes because a typical LLN operates at a very slow pace, and a typical device is like a three-toed sloth that would sleep more than a cat. We even had a requirement to produce an 'infinite' lifetime for the likes of light bulbs but never took it that slow. We could change the format but that would not be backward compatible.
"

For memory, RPL advertises the lifetime unit in the configuration option, and the resulting lifetime can be sent in one octet in DAO. 
We could encode lifetime differently here as well, like splitting the 2 octets, but that would break backward compatibility.

Any idea?

Pascal