Re: [homenet] Next Steps for HNCP

2014-11-17 Thread Michael Richardson

Pierre Pfister  wrote:
>> HNCP is too chatty for the LLN to deal with. do we have any numbers?
>> presumably one could design a stub HNCP, where the peer only received
>> messages relevant to it, possibly even with a HNCP sleep proxy.


> We could try to make HNCP more Low-Power-friendly, but there will
> always be cases where HNCP will kill LP nodes because HNCP provides
> network-wide state synchronization (e.g. a buggy node keeps sending
> changing updates).

Huh?  Nobody is suggesting HNCP or RP (other than RPL) for the LLN.
It's about the gateway (which in James' case, is the Nest Thermostat
platform) to the LLN which is also on the home wifi (does it have a cable
too?).  I don't know the Nest at all, I assume that it has a power source,
my digital (non-smart) one gets 12V from the furnace.

The gateway has to run LLN-happy protocol (RPL or another), as well as
something to advertise the LLN's stub network (probably a different ULA than
the homenet; no renumbering allowed) into the homenet.

James has come with the belief that his gateway would be unable to run RP.
I think is fear is unfounded.


-- 
]   Never tell me the odds! | ipv6 mesh networks [ 
]   Michael Richardson, Sandelman Software Works| network architect  [ 
] m...@sandelman.ca  http://www.sandelman.ca/|   ruby on rails[ 




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Re: [homenet] Next Steps for HNCP

2014-11-17 Thread Pierre Pfister
> 
> 
> while 2 and 3 require participation in HNCP, my worry is that even HNCP is 
> too chatty for the LLN to deal with. do we have any numbers? presumably one 
> could design a stub HNCP, where the peer only received messages relevant to 
> it, possibly even with a HNCP sleep proxy.


We could try to make HNCP more Low-Power-friendly, but there will always be 
cases where HNCP will kill LP nodes because HNCP provides network-wide state 
synchronization (e.g. a buggy node keeps sending changing updates).

IMO, the reason why the ‘buddy’ approach was relevant for Low-Capacity devices 
like James’ is that HNCP could be useful for different things (e.g. advertise a 
Delegated Prefix), which we can’t really do with a routing protocol. So instead 
of having HNCP + RP, it would be HNCP alone. In which case the chattyness of 
HNCP doesn’t matter much. 

That said, I think the chatyness of both HNCP and the RP should be taken into 
account, as a ‘weak' requirement (i.e. it should not override already existing 
requirements).

Additionally, I **don’t** think the WG should consider defining an 
HNCP-proxying mechanism. If HNCP is successful, and if the need appears to be 
strong, OK. But we should make something that works without such support first.

- Pierre
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Re: [homenet] Next Steps for HNCP

2014-11-16 Thread Pierre Pfister


> Pierre,
> 
>>> while 2 and 3 require participation in HNCP, my worry is that even HNCP is 
>>> too chatty for the LLN to deal with. do we have any numbers? presumably one 
>>> could design a stub HNCP, where the peer only received messages relevant to 
>>> it, possibly even with a HNCP sleep proxy.
>> 
>> 
>> We could try to make HNCP more Low-Power-friendly, but there will always be 
>> cases where HNCP will kill LP nodes because HNCP provides network-wide state 
>> synchronization (e.g. a buggy node keeps sending changing updates).
>> 
>> IMO, the reason why the ‘buddy’ approach was relevant for Low-Capacity 
>> devices like James’ is that HNCP could be useful for different things (e.g. 
>> advertise a Delegated Prefix), which we can’t really do with a routing 
>> protocol. So instead of having HNCP + RP, it would be HNCP alone. In which 
>> case the chattyness of HNCP doesn’t matter much. 
>> 
>> That said, I think the chatyness of both HNCP and the RP should be taken 
>> into account, as a ‘weak' requirement (i.e. it should not override already 
>> existing requirements).
> 
> I think we need to separate the two discussions. let's start a separate work 
> item for peering with LLNs.

You’re right.

> 
>> Additionally, I **don’t** think the WG should consider defining a full 
>> HNCP-proxying mechanism. If HNCP is successful, and if the need appears to 
>> be strong, OK. But we should make something that works without such support 
>> first. Proposal #1 is, IMO, a correct trade-of.
> 
> if proposal #1 is for peering with LLNs I don't think that's correct. firstly 
> we need to get the requirements better defined.

I agree, the discussion is a dead-end if we don’t define whether the Low-Power 
stub device can run HNCP or not. IMHO I don’t think we want to think about 
situations where it can’t.

> and by the way overloading the assigned prefix TLV as a "register external 
> route" option is pretty ugly. you'll then get assigned prefixes which aren't 
> even more specifics out of the delegated prefix. keep the prefix assignment 
> mechanism clean please.

In James’ problem, the prefix would actually belong to an advertised DP. But I 
agree that could not be always the case.
There may be other possibilities, like defining a dedicated TLV. I don’t know 
which is the best design choice. 

> 
> cheers,
> Ole
> 

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Re: [homenet] Next Steps for HNCP

2014-11-15 Thread Ole Troan
Pierre,

>> while 2 and 3 require participation in HNCP, my worry is that even HNCP is 
>> too chatty for the LLN to deal with. do we have any numbers? presumably one 
>> could design a stub HNCP, where the peer only received messages relevant to 
>> it, possibly even with a HNCP sleep proxy.
> 
> 
> We could try to make HNCP more Low-Power-friendly, but there will always be 
> cases where HNCP will kill LP nodes because HNCP provides network-wide state 
> synchronization (e.g. a buggy node keeps sending changing updates).
> 
> IMO, the reason why the ‘buddy’ approach was relevant for Low-Capacity 
> devices like James’ is that HNCP could be useful for different things (e.g. 
> advertise a Delegated Prefix), which we can’t really do with a routing 
> protocol. So instead of having HNCP + RP, it would be HNCP alone. In which 
> case the chattyness of HNCP doesn’t matter much. 
> 
> That said, I think the chatyness of both HNCP and the RP should be taken into 
> account, as a ‘weak' requirement (i.e. it should not override already 
> existing requirements).

I think we need to separate the two discussions. let's start a separate work 
item for peering with LLNs.

> Additionally, I **don’t** think the WG should consider defining a full 
> HNCP-proxying mechanism. If HNCP is successful, and if the need appears to be 
> strong, OK. But we should make something that works without such support 
> first. Proposal #1 is, IMO, a correct trade-of.

if proposal #1 is for peering with LLNs I don't think that's correct. firstly 
we need to get the requirements better defined. and by the way overloading the 
assigned prefix TLV as a "register external route" option is pretty ugly. 
you'll then get assigned prefixes which aren't even more specifics out of the 
delegated prefix. keep the prefix assignment mechanism clean please.

cheers,
Ole

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Re: [homenet] Next Steps for HNCP

2014-11-15 Thread Pierre Pfister
> 
> 
> while 2 and 3 require participation in HNCP, my worry is that even HNCP is 
> too chatty for the LLN to deal with. do we have any numbers? presumably one 
> could design a stub HNCP, where the peer only received messages relevant to 
> it, possibly even with a HNCP sleep proxy.


We could try to make HNCP more Low-Power-friendly, but there will always be 
cases where HNCP will kill LP nodes because HNCP provides network-wide state 
synchronization (e.g. a buggy node keeps sending changing updates).

IMO, the reason why the ‘buddy’ approach was relevant for Low-Capacity devices 
like James’ is that HNCP could be useful for different things (e.g. advertise a 
Delegated Prefix), which we can’t really do with a routing protocol. So instead 
of having HNCP + RP, it would be HNCP alone. In which case the chattyness of 
HNCP doesn’t matter much. 

That said, I think the chatyness of both HNCP and the RP should be taken into 
account, as a ‘weak' requirement (i.e. it should not override already existing 
requirements).

Additionally, I **don’t** think the WG should consider defining a full 
HNCP-proxying mechanism. If HNCP is successful, and if the need appears to be 
strong, OK. But we should make something that works without such support first. 
Proposal #1 is, IMO, a correct trade-of.

- Pierre
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Re: [homenet] Next Steps for HNCP

2014-11-15 Thread Dave Taht
I think this conversation has got off on the wrong foot - the start of
it was about routing protocol choice, and the other was how to
interoperate with a stubby nest network in hncp.

On Sat, Nov 15, 2014 at 8:43 PM, Michael Richardson
 wrote:
>
> Mark Townsley  wrote:
> > routing protocol.  A technical solution was proposed and discussed
> > ("proposal #1"), using the attached slides. "Proposal #2" in the
> > attached slide deck explored one way to support "HNCP Fallback" plus a
> > to-be-named "Routing Protocol" at the same time in a Homenet. Consensus
>
> I think that the two things are not mutually exclusive, or did I 
> mis-understand?
>
> --
> Michael Richardson , Sandelman Software Works
>  -= IPv6 IoT consulting =-
>
>
>
>
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