Re: [pcp] PREFIX64 PCP Option for NAT64: draft-boucadair-pcp-nat64-prefix64-option

[<[e-mail]>]

Re-,

Please see inline.

Cheers,
Med 

>-----Message d'origine-----
>De : Simon Perreault [mailto:[e-mail]] 
>Envoyé : jeudi 6 septembre 2012 16:00
>À : BOUCADAIR Mohamed OLNC/NAD/TIP
>Cc : [e-mail]
>Objet : Re: [pcp] PREFIX64 PCP Option for NAT64: 
>draft-boucadair-pcp-nat64-prefix64-option
>
>Mohamed,
>
>Thanks for the very detailed answer! The background story is much 
>clearer to me now.
>
>Le 2012-09-06 09:20, [e-mail] a écrit :
>>> Consider a PCP client that receives a MAP response containing a
>>> PREFIX64 option. Does the option apply a) only to the mapping
>>> contained in the MAP response, or b) to all future mappings as
>>> well?
>>
>> Med: I'm tempted to say the prefix will be used for all mappings
>> associated with the same PCP server. A record to associate a PCP
>> server and a PREFIX64 should be maintained by the client. We need to
>> check if there are scenarios where the same PCP Server controls
>> NAT64s configured with distinct PREFIX64 servicing the same IPv6-only
>> host.
>
>I still have a problem with this. The problem is that the 
>PREFIX64 data 
>should not be associated with a MAP request because it is 
>global to the 
>server. Returning it as part of a MAP response makes no sense to me.

Med: I see it from a distinct perspective: return it in the MAP says to the PCP Client this is the prefix the NAT64 will use when translating received IPv4 packets matching the instantiated entry. The question whether we can extrapolate it to all mapping is a valid one. 

>
>Suggestion: why not create a new opcode for querying server-global 
>parameters? The PCP client would use this opcode once, get the 
>PREFIX64 
>data in the response, then would do MAP requests separately as 
>usual. I 
>think this would result in clearer semantics and implementations.

Med: I'm open to evaluate which approach is better: new opcode vs. new option. We need first to agree this is valid problem to solve.

>
>Simon
>-- 
>DTN made easy, lean, and smart --> http://postellation.viagenie.ca
>NAT64/DNS64 open-source        --> http://ecdysis.viagenie.ca
>STUN/TURN server               --> http://numb.viagenie.ca
>