Subject: [Lwip] problems and possible directions

From: Zhen Cao <[email-masked]>
Date: Tue, 7 Sep 2010 23:54:56 +0800

Dear All,

For the lightweight design interest group, we plan to have more
discussion at IETF Beijing meeting. The following is my take of the
problems and possible working directions.  Any comments and ideas are
appreciated.  Thank you in advance.

Regards,
Zhen

------------------
Technologies are evolving, but we keep inventing smaller things. For
most devices that are commonly used in the Internet of Things
applications, they are resource constrained. First, they are built on
top of the constrained computing platform, e.g., with 8-bit
microcontrollers and limited RAM and ROM.  Secondly, the connectivity
between the nodes and the outside network is constrained, e.g., some
links go down to 20kbps and with limited delivery probability.

Problems and working directions include:

1. TCP header compression. Many applications use TCP as the transport
to provide some robustness and reliability. Since the IEEE 802.15.4
frame size is very limited and not able to accommodate much protocol
headers, it is desirable to provide header compression for TCP.
6LowPan WG has defined the IPv6 header compression, and UDP header
compression.  But there is not standard TCP header compression
mechanism.

2. Lightweight transport protocol. In some lightweight operation
systems, for example, Contiki and TinyOS, it turns out that the TCP
codes take up to 50% of the code size and the switch between different
TCP states consumes much memory size.  It is desirable to design a new
transport layer protocol to do flow control and congestion control.

3. Lightweight key exchange protocol. IEEE 802.15.4 has defined MAC
security , but there is no keying there and applications are
struggling if they do not have the keys. Most security protocols are
resource consuming, and it is difficult to apply them directly to
smart devices. For example, there are some proposals of making Host
Identity Protocol diet so as to provide keys for the MAC layer.

4. Profiles for different application scenarios. For different
scenarios, different set of protocols could be applied. It is
desirable to have a document specifying those profiles and benefit
application deployment.

5. Documentation of Implementation techniques.  There are lots of
tricks to make the IP stack lightweight so as to fit into the very
constrained nodes.   But these techniques are not well documented
formally.  In order to facilitate the ongoing/future developers on
these constrained platforms, there is a need to document these
activities and common technologies.
--------------------------------

---

From: Hui Deng <[email-masked]>
Date: Fri, 10 Sep 2010 08:38:38 +0800

Hi zhen

I see the problem which has been discussed last time is quite clear,
but you may need a ID to discuss about scenario and PS asap?

thanks

-Hui

2010/9/7 Zhen Cao <[email-masked]>

> _______________________________________________
> Lwip mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/lwip
>

---

From: Zhen Cao <[email-masked]>
Date: Sun, 12 Sep 2010 22:13:00 -1000

Yes, we are working on it right now. Thank you for the suggestion.