Re: [6lo] SCHC HC over IEEE 802.15.4: 2. Multihop route-over approaches

[Michael Richardson <[e-mail]>]

{I haven't read your draft, but I'll get to it}

Carles Gomez Montenegro <[e-mail]> wrote:
    > - “Straightforward Route-Over” incurs the lowest header overhead, as it
    > only requires the SCHC Dispatch (1 byte). However, it is the most
    > demanding approach in terms of memory usage, since all network nodes
    > (including intermediate nodes) need to store all the Rules in use in

At this point all constrained networks are purpose-built, usually for a
single application.  (This is not how many thought it would work, if you go
back to 2007ish...)
As I understand SCHC, the Rules are not dynamic, and so a network built using
this method would be provisioned correctly.

    > - “Tunneled, RPL-based Route-Over” incurs greater header overhead (with
    > some cases in the order of 12-16 bytes, although it may be more

I'm guessing that this overhead is in the RH3, and that in the absense of
SCHC, that we'd still have to spend that overhead?

    > - “Pointer-based Route-Over approach” also only requires the endpoints
    > to store the Rules they will need to communicate with other

This feels like some kind of new optimized source routing mechanism?

    > A question that has been raised is whether we might want to keep all
    > three route-over approaches in the document or reduce the number of
    > such approaches. As authors we are in favor of enabling all of them,
    > since they may be complementary, and the most suitable one can be
    > chosen for each deployment.

I don't object to multiple methods in theory, if there is a way to clearly
articulate (at build time), which one will be used.  But it would be better
for mindshare and debugging, and code maintenance to have fewer methods.

--
Michael Richardson <[e-mail]>   . o O ( IPv6 IøT consulting )
           Sandelman Software Works Inc, Ottawa and Worldwide