Subject: [6tisch] How to recover uri-host

From: Qin Wang <[email-masked]>
Date: Tue, 29 Apr 2014 02:39:39 -0700 (PDT)

Hi all,

During 6top group discussion and last Friday's 6tisch call, a issue about how to handle uri-host while CoAP message is carried in Wrapping IE was raised. Two approaches are mentioned as follows.

(1) no uri-host option. CoAP parser gets the host address from MAC header.
(2) uri-host= target node address. 

Approach (1) saves bits, while approach (2) can keep the CoAP parser to conventional CoAP parser closer.

I think we may have another approach in the middle. That is, IE parser adds the uri-host=MAC address to the IE's payload, i.e. the CoAP message, before passing it to CoAP parser; and the IE formatter takes the uri-host field away when it puts CoAP message into WrappingIE.

What do you think?

Thanks
Qin