OK, I think Phil is commenting on:
This is obviously far below the minimum IPv6 packet size of 1280 octets,
1280 octets is not necessarily the minimum IPv6 packet size, but you can set 1280 as the MTU size which would mean the maximum packet size.
This point is clear in the format draft, draft-ietf-6lowpan-format-03.txt but it should be clarified in the PS draft as well.
Regards,
Behcet
This is obviously far below the minimum IPv6 packet size of 1280 octets,
1280 octets is not necessarily the minimum IPv6 packet size, but you can set 1280 as the MTU size which would mean the maximum packet size.
This point is clear in the format draft, draft-ietf-6lowpan-format-03.txt but it should be clarified in the PS draft as well.
Regards,
Behcet
----- Original Message ----
From: Philip Levis <[EMAIL PROTECTED]>
To: Behcet Sarikaya <[EMAIL PROTECTED]>
Cc: Geoff Mulligan <[EMAIL PROTECTED]>; 6lowpan <[email protected]>
Sent: Thursday, July 20, 2006 10:52:49 AM
Subject: Re: [6lowpan] WG Last call on Problem Statement Document
From: Philip Levis <[EMAIL PROTECTED]>
To: Behcet Sarikaya <[EMAIL PROTECTED]>
Cc: Geoff Mulligan <[EMAIL PROTECTED]>; 6lowpan <[email protected]>
Sent: Thursday, July 20, 2006 10:52:49 AM
Subject: Re: [6lowpan] WG Last call on Problem Statement Document
On Jul 19, 2006, at 8:10 PM, Behcet Sarikaya wrote:
> I agree with Phil, I think we should have his consideration
> considered seriously.
> Regarding his question, in the format draft, 802.15.4 MAC layer is
> assumed and the frame sizes are from IEEE standard. This WG assumes
> that even the light sensors support 802.15.4 MAC (kind of like
> Telos motes). In that sense this WG is addressing futuristic sensor
> nodes on which IP stack can be implemented. How close that future
> be, we do not know.
>
You can totally write an IP stack -- even a TCP stack -- on sensor
nodes today, admittedly the ones that have the biggest
microcontrollers you can buy (atmega128L, MSP430F1611, etc.). The TCP
stack might not have a lot of RAM for windowing and high performance,
but that's rarely the goal. You can do it.
I don't think the requirements the document implies are unrealistic
or onerous. As I said, you have to cut the line somewhere. My comment
was just that they *do* preclude smaller nodes whose storage cannot
hold a complete IPv6 packet, and it might be useful to note as such,
since the document is defining the problem statement, and therefore
the problem scope.
Phil
> I agree with Phil, I think we should have his consideration
> considered seriously.
> Regarding his question, in the format draft, 802.15.4 MAC layer is
> assumed and the frame sizes are from IEEE standard. This WG assumes
> that even the light sensors support 802.15.4 MAC (kind of like
> Telos motes). In that sense this WG is addressing futuristic sensor
> nodes on which IP stack can be implemented. How close that future
> be, we do not know.
>
You can totally write an IP stack -- even a TCP stack -- on sensor
nodes today, admittedly the ones that have the biggest
microcontrollers you can buy (atmega128L, MSP430F1611, etc.). The TCP
stack might not have a lot of RAM for windowing and high performance,
but that's rarely the goal. You can do it.
I don't think the requirements the document implies are unrealistic
or onerous. As I said, you have to cut the line somewhere. My comment
was just that they *do* preclude smaller nodes whose storage cannot
hold a complete IPv6 packet, and it might be useful to note as such,
since the document is defining the problem statement, and therefore
the problem scope.
Phil
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