[Lightning-dev] Receiving via unpublished channels

[Hiroshi UENO]

Hi, ZmnSCPxj.

Thank you for your reply and explanation.
I will implement it like c-lightning to ptarmigan.


Regards,
nayuta-ueno

On 2018/05/09 14:17, ZmnSCPxj wrote:
> Good morning Nayuta-ueno,
> 
>> I have some questions.
>>
>> -   Does `channel_update` send only for `announce_channel == 0`(in`open_channel.channel_flags`) ?
> 
> No, C-lightning always send it.
> 
>> -   Does `channel_update` send every time after `funding_locked` sending(established and reconnection) ?
> 
> For C-lightning, the temporary ones are sent after `funding_locked` has been sent by both sides, as well as reconnection (only if both sides have sent `funding_locked`).  The only time they are not, is if the channel is shutting down (and so any fee updates would be pointless, as the channel will no longer be useable for forwarding, sending, or receiving) or the channel has already achieved the announcement depth.
> 
> After announcement depth, "normal" `channel_update` should get sent after a `channel_announcement`, and not the temporary ones.
> 
> Regards,
> ZmnSCPxj
> 
>>      
>>      Regards,
>>      
>>      nayuta-ueno
>>      
>>      On 2018/04/27 8:35, ZmnSCPxj via Lightning-dev wrote:
>>      
>>
>>> Good morning list,
>>>
>>> While implementing support for `r` field in invoices, I stumbled upon some issues regarding creating invoices with `r` fields.
>>>
>>> In order to receive via an unpublished channel, we need to know what onLightning fees the other side of that channel wants to charge.  We cannot use
>>>
>>> our own onLightning fees because our fees apply if we were forwarding to the other side.
>>>
>>> However, in case of an unpublished channel, we do not send channel_announcement, and in that case we do not send channel_update.  So the other side of
>>>
>>> the channel never informs us of the onLightning fees they want to charge if we would receive funds by this channel.
>>>
>>> An idea we want to consider is to simply send `channel_update` as soon as we lock in the channel:
>>>
>>> https://github.com/ElementsProject/lightning/pull/1330#issuecomment-383931817
>>>
>>> I want to ask the other LN implementations (lnd, eclair, ucoin, lit) if we should consider standardizing this behavior (i.e. send `channel_update`
>>>
>>> after lockin  regardless of published/unpublished state).  It seems back-compatible: software which does not expect this behavior will simply drop the
>>>
>>> `channel_update` (as they do not follow a `channel_announcement`).
>>>
>>> In any case, what was the intended way to get the onLightning fee rates to put into invoice `r` fields for private routes?
>>>
>>> Regards,
>>>
>>> ZmnSCPxj
>>>
>>> Lightning-dev mailing list
>>>
>>> Lightning-dev at lists.linuxfoundation.org
>>>
>>> https://lists.linuxfoundation.org/mailman/listinfo/lightning-dev
>>
>> --
>>
>> //株式会社Nayuta
>>
>> // 上野　寛(Hiroshi Ueno)
>>
>> // email: ueno at nayuta.co
>>
>> Lightning-dev mailing list
>>
>> Lightning-dev at lists.linuxfoundation.org
>>
>> https://lists.linuxfoundation.org/mailman/listinfo/lightning-dev
> 
> 

-- 
//株式会社Nayuta
//  上野　寛(Hiroshi Ueno)
//     email: ueno at nayuta.co