Moderator:
Please remove me from the mailing list. Thanks.
Bill Melendez
HEMS Technology
--- On Fri, 4/3/09, Michel Kohanim <michel@universal-devices.com> wrote:
From: Michel Kohanim <michel@universal-devices.com>
Subject: RE: [smartgrid-interest] What's wrong with having devices communicate in their own native languages
To: smartgrid-interest@lists.oasis-open.org
Date: Friday, April 3, 2009, 12:04 PM
I think we now agree on a lot of things the most important of which is the definition of the model. As far as addressing, prior to REST, I would’ve agreed with you. But using REST, one can address even a SQL Field, within a specific record of an object in a specific location and so on an so forth. As long as we keep a neutral addressing scheme (such as URLs/REST) we could address any individual object and even properties of that object either behind a gateway or on the Internet.
With kind regards,
********************************
Michel Kohanim, C.E.O
Universal Devices, Inc.
(p) 818.631.0333
(f) 818.708.0755
http://www.universal-devices.com
********************************
From: Brian Frank [mailto:brian@skyfoundry.com]
Sent: Thursday, April 02, 2009 12:18 PM
To: michel@universal-devices.com
Cc: smartgrid-interest@lists.oasis-open.org
Subject: Re: [smartgrid-interest] What's wrong with having devices communicate in their own native languages
I think it depends on the capabilities of the end device. We are working on some of those issues right now. You are right - some devices don't have the horse power to implement effective end-to-end security. For example 6LoWPAN devices aren't going to run TLS. So router/gateway nodes do need to provide some of those capabilities on behalf of the lower end devices.
However, security, QOS, firewalls, etc tend to be orthogonal to core data models and formats. A gateway/router node can add authentication, encryption, caching without fundamentally altering the end-to-end data communications. This sort of thing happens all the time in IT networks (such as VPNs). But I definitely think this isn't black and white - there is a spectrum between "router" and "gateway".
To me the most important point is that the abstract data model is shared end-to-end (even if
multiple encodings of that model are used in between). But it turns out naming and addressing is extremely difficult to separate from an abstract data model. That would be like taking URLs out of the Web, or SQL out of RDBMS. So one of the most important things IP end-to-end brings to the party is its global IP address space. That in turns lets me use standard URIs to identify data, which in turns lets me wire up relationships between data just like the Web does today.
Brian, I almost agree with you but I have a question: in your analogy of gateway/routers, where do you see QOS, Firewall, IPSec, SNMP, etc. be implemented at? I am sure you do not mean that all end points will implement QOS, IPSec, etc. and, therefore, at least there are some high level functions that the end points will not understand regardless of their protocol. Does this mean endpoints should not be IP based, no, not at all. It just means that there are system boundaries which have not yet been well defined. As such, to me, talking about the transport protocol now without boundary requirements is tantamount to building a software system based on an operating system (of course, nothing wrong with this but not very scalable).
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