[Tinyos-host-mote-wg] [Tinyos-2.0wg] 2005/05/25 Telecon Notes

Kristin Wright l.kristin.wright at gmail.com
Tue May 31 18:09:48 PDT 2005


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Notes from 05/25/2005 TinyOS 2.0 Working Group Telecon

05/25/2005 Agenda
-------------------
- ADC update (Jan Hauer)
- Other status items (All)
- AM layer issues (Phil Levis)

05/25/2005 Action Items
------------------------
- Phil Levis (with Jan): go over TEP 101 (ADC) and TEP 109
  (Sensorboards)to ensure compatibility
- Phil Levis: will send out proposal for what address definitions 
  OSKI can assume

05/25/2005 Tentative Agenda
----------------------------
Not discussed.

05/25/2005 Discussion Notes
-----------------------------------------------------------------------------

ADC Update
----------
- dgay (David Gay): should put out that we've finalized the TEP; recommend that
  people read and comment
-- kevin (Kevin Klues): brief summary:
  - will not have an HIL by traditional sense due to the variety in the
    underlying hardware; the HIL is taken over by the sensorboard TEP (109)
  - instead will have 2 HALs;
	- HAL1: traditional (provides all functionality)
   	- HAL2: 
	  - has AcquireData parameterized interface
	  - still platform dependent; how you wire depends on
	    port (chip-independent but platform-dependent
  - vlado (Vlado Handziski): opportunity to clear up confusion in TEP 
	sensor wrappers: very normal HIL interfaces
- dgay: need to ensure that tep 101 and tep 109 fit nicely together
- pal (Phil Levis): will do this by Sunday; will include Jan in the process

Status
-------
- kwright (Kristin Wright): sent in email
  - https://mail.millennium.berkeley.edu/pipermail/tinyos-2.0wg/2005-May/000901.html
  - https://mail.millennium.berkeley.edu/pipermail/tinyos-2.0wg/2005-May/000902.html  
  - vlado: to coordinate msp spec files with kwright
- vlado: has anyone tested TOSComm on linux?
  - dgay: yes, he's been using it 
- dgay: checked in packet stuff; removed dependencies on net.tinyos.message
- pal: oski: active messages, using services, next step is to
	make sure services all work; basic model (instantiation 
	working pretty well)
- dgay: eyes radio code appearing? 
	- kevin: through HPL layer of radio
	  - done by next week 
- imote2: 
  - tracking down a bug w/clock frequency 
  - not sure if hw or sw	
  - probably won't take much longer
  - finally found the libc; gave info to kwright

Miscellaneous radio issues 
------------------------------
- phil: basic question: what is the HIL to our radio?  is it an AM?
	with a particular address form (2 bytes) or something below
	that?
  - example: if my underlying mac layer has an address, is the AM address the 
	same, different?
  - current approach: AM in HIL
- vlado: a lot of issues we have to find answers for
  - start at HPL defines interaction of radio / busses
  - HAL should be something that allows x-platform interfaces
- phil: how does that affect HIL decision?
- vlado: of the opinion that HPL/HAL close to hardware; 
  anything on top is protocol
  - proposes ending with HIL way below active messages; all csma radios
    have all the same HIL; another HIL for bluetooth radios
  - on top of that (bluetooth/CSMA) are the protocols (AM)
  - example: radioCRC and then on top we have AM
- philb (Phil Buonnadonna): include an event handler id, and packet
- dgay: and address? 
- philb: no -- address can be provided by underlying layers; we've enjoyed
  ordering that all the layers understand,  but that ordering is
  hard to maintain. If IP/zigbee become important in sensor network stacks,
  this blurring could be a mistake; more strictly enforced layers
  might allow greater flexibility to explore networking layers in the future
- phil: how the address is defined and at what levels the addresses are
  seen not necessarily straightforward.
  ex: in 15.4, only get ACK at hw level if you have the 15.4 addresses 
  in the chip; what's the relationship between those addresses and 
  AM addresses?
  - it would be much cleaner if there was a separation, but blurring may
    lead to greater efficiency/greater functionality
- dgay: what if the lower layers talked to AM they specify an address
  as an opaque address_t type? 
  - should be decided and exposed at the CSMA level or we don't	get ACK
  - propose a strawman poll: which CSMA some size integer?
- vlado: some radios don't care 
- CSMAC radio component will have to simulate them (address) to that component
- pal: with TDMA, must have address to know when to send 
- philb: 
  - reason to balk at 2-byte thing is that we're reinventing a 
    network layer for tinyos; 
  - making the HIL as generic as possible allows the networking standard 
    to mature with experience
  - could say it's 4 bytes address and a len, but avoid bleeding that 
    across the layers such that trying to put IP in wouldn't work
- dgay: even if we define an address size 
- phil: 
  - understand concern about bleeding, but network stack is going
    that way; pure layering seems untenable in the long term 
  - just because there's a certain HIL defined doesn't mean that it's
    the *only* HIL; in fact, the platform doesn't have to provide it
	ex: hamamatsu HIL, if you don't have it you don't implement the 
	interface
    - HIL are high-level services
    - can simplify declare the 'my platform is compliant with tep xyz';
      if it isn't compliant with AM TEP, that's okay
- dgay: 
  - there could be alternative AM implementations; don't have to
    commit now to a particular HIL for all radios for all time
- dgay: for this HIL that has an address, do we have a broadcast interface?
  - phil: yes
  - vlado: but it seems like the same case as uart; if we solve uart
    with wiring, then broadcast seems analagous
- vlado: do we have an agreement on what's below the hil layer?
  - dgay: up to radio
  - vlado: do we want to support running different protocols 
    (TDMA/mac layer/physical layer)
- dgay: should answer the question: what can phil assume when 
  implementing oski?
- vlado: married with phy/mac/everything in one so you 
  have to use that; that's a problem 
- phil: are you familiar with rfm radio? originally, the rfm used a similar
  radio component (phy/mac/all-in-one)
  - jhill decomposed stack as a result of ucla's desire to isolate and
    experiment on the MAC layer; merged back in cc1000 for efficiency
- vlado: doesn't like that everything is in HIL up to app
- dgay: could have an HIL for all CSMA radios and also an AM HIL... 
- phil: if you have hw support for queueing, that's going to be in your HIL;
  if you don't, there's a hw-independent HIL that provides queueing
- dgay: can we just define a set of useful for more-than-one platform 
  abstractions and build them?
- vlado's abstraction: HIL for byte radios good but obviously not
  available on all platforms
- dgay: need to define for phil what he can expect from underlying layers
  - how about: oski will assume CSMA radio with address and length
- philb: does the packet include the src or dest?
- dgay: destination 
- vlado: if you leave off source then acks are a problem
- phil: not sure we're going to resolve today because these decisions 
  will have far-reaching consequences 
  - will send out a proposal
- dgay: should we have a separate discussion about different kinds of radios?
- vlado: think we should std packet format just as it is now; we have
	a tinyos message; everyone able to implement by defining it
- dgay: actually, msp430 and avr have different message structures
- phil: 15.4 address does not have a source 
- vlado: how do they ack?
  - phil: think jonathan hui said sequence numbering
- phil: will send out a proposal; proposal may take the form of 
  modifying TEP 05 (which has RadioPacket)
- all agree we need some ByteLevel, PacketLevel interfaces
- dgay: do we care enough about cc1000 to support in future? more a decision
  in effort -- not worth doing for the cc1000.
- vlado: will get whole implementation for free from tu-berlin if we can
  agree on a byte-radio HIL
- dgay: suggest we delay separate discussion about byte radio until
  after pre2 release or we'll never get that done




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