Re: [multipathtcp] Fwd: [rrg] New Paper On Name-Oriented Sockets Interface

[Zhen Cao <[e-mail]>]

On Wed, Dec 2, 2009 at 6:34 PM, Rémi Després <[e-mail]> wrote:
> Hi Joe,
>
> Comments below.
> Stuart Cheshire added to the list (AFAIK, the leading advocate of
> connect-by-name).
>
> Regards,
> RD
>
> Joe Touch wrote :
> ...
>>
>> Rémi Després wrote:
>
> ...
>>>
>>> I haven't studied all details of Christian's proposal, but I fully
>>> support that:
>>> - A name-capable API is an essential objective.
>
>
>> I'm not sure this is a desirable objective.
>>
>> When you specify a name, you're not specifying a single address; you're
>> specifying any one of a set of addresses. It's presumed that these are
>> equivalent, but not that they are to the same host. A name-based system
>> could easily end up with a sequence of connections going to different
>> hosts.
>>
>> That's avoided today as:
>>
>>        adr = first(dns("name"))  -- or adr = pickone(dns("name"))
>>        connect(adr)
>>        connect(adr)
>>        connect(adr)
>> There doesn't seem to be a way to achieve this with:
>>
>>        connect("name")
>>        connect("name")
>>        connect("name")
>>
>> This destroys the utility of HTTP cookies, e.g.
>
> Note that:
> - If backward compatibility is maintained, as required in the proposal, a
> name-capable API doesn't imply that it be address-unable.

I have a question here. How does a host know if its peer support the
name oriented sockets or not?

> - Connect-by-name is already mentioned for Shim6 in RFC 5533 - sec. 13, (a
> way to save time when multiple addresses have to be tried for a given domain
> name)
>
> Applications that may depend on successive connections to go to the same
> host, they can use:
>        ConnectByName(name) which returns the chosen adr
>        Connect(adr)
>        Connect(adr)
>        Connect(adr)
>
> The useful novelty ahead is IMHO the following:
> - If a connection initiator includes its domain name in its connection
> request (e.g. in a TCP option) the API of the reached application, if it is
> name-capable, provides both the address AND the name of the connection
> initiator.
> - A consistency check between address and name is done by the transport laye
> before connection acceptance. This check needs only a DNS query. It is
> therefore compatible with DNS dynamic updates and DNSSEC (no need for a DNS
> supported reverse mapping).
>
>
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