Re: [Bitcoin-development] NODE_EXT_SERVICES and advertising related services

[Jeff Garzik <jgarzik@bitpay.com>]

This is not a generic "I run a website!" advertisement feature.
NODE_EXT_SERVICES is tightly focused on services that exist
if-any-only-if a P2P bitcoin node (bitcoind) is reachable via the same
advertised address.

You may usefully create overlay networks of specialized services.



On Fri, Aug 8, 2014 at 6:41 AM, Christian Decker
<decker.christian@gmail.com> wrote:
> I wonder whether we actually want to support this kind of advertisement in
> the P2P protocol. We have a working mechanism for protocol extensions in the
> P2P network (service flags) so this is obviously only for services that are
> not P2P extensions, so why have them in there at all?
>
> I'd argue that a parallel network, external to Bitcoin, could take over the
> task of advertising external services.
>
> Regards,
> Chris
>
> --
> Christian Decker
>
>
> On Fri, Aug 8, 2014 at 11:26 AM, Wladimir <laanwj@gmail.com> wrote:
>>
>> On Fri, Aug 8, 2014 at 12:15 PM, Wladimir <laanwj@gmail.com> wrote:
>> > On Fri, Aug 8, 2014 at 12:01 PM, Mike Hearn <mike@plan99.net> wrote:
>> >>> He wants to use it to advertise services that are not part of the P2P
>> >>> protocol itself, but run on a different port. Reserving services bits
>> >>> for those is not acceptable.
>> >>
>> >>
>> >> Why not? Does the port matter much?
>> >
>> > Yes. The services bits are for advertising services on the P2P
>> > network. That's not open for discussion.
>>
>> It also wouldn't work. A bit is not enough to find an external service
>> except in the naive case where the advertised service would have a
>> fixed port. Not even bitcoind has a fixed port. So there needs to be a
>> mechanism to find how to connect to the 'external service'. This is
>> provided by the proposed extension.
>>
>> It would in principle be possible to advertise an extra service bit
>> *in addition to* this one, to make it easier to find through the addr
>> mechanism. But it  would be confusing and IMO an abuse of P2P service
>> bits.
>>
>> Wladimir
>>
>>
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>
>
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-- 
Jeff Garzik
Bitcoin core developer and open source evangelist
BitPay, Inc.      https://bitpay.com/