Re: [Anima-bootstrap] peer and domain [was BRSKI State Machine]

[Brian E Carpenter <[e-mail]>]

On 18/10/2016 21:03, Michael Behringer (mbehring) wrote:
>> -----Original Message-----
>> From: Brian E Carpenter [mailto:[e-mail]]
>> Sent: 18 October 2016 01:18
>> To: Max Pritikin (pritikin) <[e-mail]>; Michael Behringer
>> (mbehring) <[e-mail]>
>> Cc: [e-mail]
>> Subject: peer and domain [was BRSKI State Machine]
>>
>>
>>
>> On 18/10/2016 12:05, Max Pritikin (pritikin) wrote:
>> ...
>>>> - I think we need to bring out more strongly that the state machine needs
>> to track peer and domain. Because, if there is a failure, the pledge should,
>> depending on the failure of course, not try the same domain again, and
>> probably not the same peer either. This isn't coming out today.
>>>> In fact, this is why I liked the "adjacency table" so much that I presented in
>> Berlin (and before): Because there you see much clearer that, if enrolment
>> fails with peer x, you may just move to the next one. As mentioned it's all
>> there, but to a new reader this won't come out clearly, I'm afraid.
>>>
>>> Yeah, I can see your point that this is buried in the text of 3.1.1 where it is
>> implied that there is a list of "services returned during each query” and in
>> failure the list processing "picks up where it left off” but thats pretty subtle.
>>
>> What exactly is the "peer" in the above text? I tend to assume it's the proxy.
>> In that case it seems to me that the discovery process (whether it's mDNS or
>> GRASP) will discover all available proxies regardless of domain. And then try
>> them in some order of preference TBD.
> 
> "peer" is an entry in the adjacency table. Yes, there may be several on an interface, of several different domains. The adjacency table discussion tries to capture that. 

Fair enough. But anyway my comment still applies: a node that is joining the ACP,
or simply updating its ACP adjacencies, will discover all available neighbors...

>  
>> Also, all of this needs to work in the absence of an ACP and therefore of the
>> ACP's adjacency table. That applies to GRASP too, because in order to
>> perform its various link-local actions, it needs to know which interfaces it has
>> and which link-local addresses it has. And it learns of its link-local neighbors as
>> a result of discovery. So while I fully appreciate the value of the adjacency
>> table, we need to be functional without it.
> 
> Now we're getting into a muddle with ANIMA vs non-ANIMA modes. (And you're right - this is important to sort out). Let's see whether we can sort that. 
> 
> Up front: This is the ANIMA WG, and we're primarily defining the behaviour of an ANIMA node. This is, IMO:
> 
> - There is an adjacency table, that observes what nodes are seen on each ANIMA-capable interface. 
> - This table is fed by discovery (primarily). 
> - Depending on the state of the node, and the state of an adjacent node, different things will happen. 
>   (see my presentation on the reference model, last IETF - all described there)
> 
> For ANIMA, we need to settle on MUST discovery methods. 
> In ANIMA, we will ALWAYS build an ACP to other nodes of the same domain. 
> 
> The adjacency table links BRSKI and ACP automatically: Once I discover a node which is in the same domain, I attempt to set up an ACP connection with that node. 

Sure. And I think I can model that with GRASP - it simply needs an objective
that includes the domain and node credentials, right?

> 
> Outside ANIMA, GRASP can be used in many other ways; BRSKI can be used to derive LDevIDs and nothing else. 
> 
> Do we agree? 

I think so. But I won't know so until I see what the ACP's API looks like.
Remember that GRASP needs to create unicast and multicast sockets, so in an
ACP regime those sockets need to be provided by the ACP.

   Brian

> Michael
> 
>> Rgds
>>     Brian
>>
>