The Lightning Network FAQ

[Carlton Banks]

Has anyone had an issue after installing 0.11 of random 100% cpu utilization?
My node just stops and goes to 100% for minutes on end. Then everything goes back to normal.
No funds in it at the moment so I'll probably roll back to 0.10

I had this with C-lightning 0.9.1 recently, but it was due to a vast number of channel updates all being gossiped at once. lnd did have a bug where cpu usage got pinned to 100%, but I thought they fixed it in 0.10

So maybe check the lnd logs that it's not expected network behavior overwhelming your hardware (you're using an rpi IIRC).

[DaveF]

Has anyone had an issue after installing 0.11 of random 100% cpu utilization?
My node just stops and goes to 100% for minutes on end. Then everything goes back to normal.
No funds in it at the moment so I'll probably roll back to 0.10

I had this with C-lightning 0.9.1 recently, but it was due to a vast number of channel updates all being gossiped at once. lnd did have a bug where cpu usage got pinned to 100%, but I thought they fixed it in 0.10

So maybe check the lnd logs that it's not expected network behavior overwhelming your hardware (you're using an rpi IIRC).

Nothing in the logs showing anything.
This one is actually not on an RPi but a Virtaulbox VM that I use for testing.
It's why I keep no funds on it and don't do any work on it.

I just use it to test new versions and then if nothing else happens put them on the "live" nodes.

Not going to have time for a few days so not going to worry about it. Once I can carve out two hours I'll open an issue on github.

-Dave

[darkv0rt3x]

Hello everyone.

I'm just starting to learn about Lightning Network.
I'm running a full bitcoin node and I decided to try c-lightning from Elements project in Debian Buster.

I have a few questions that I know are quite noob, but if I understand them right from the beginning, my learning process will be much faster and reliable and also less prone to error.

I'm using solely the command line because I consider that I can learn in much more deep the way the network works and get used/known to the existing commands rather than just use front ends for the node and just get what they give me.

So, I already connected to a few nodes with success behind Tor. I also connected to a firend's node. So, connectivity is all good.

Questions are more theoretical, I guess.

For instance:
1.(a) Do I need any address to receive payments? If we don't need an address, (b) why does c-lightning software has a command to get a new address? If we need one, (c) can it be a bech32?
2. I'm still not sure if invoices are just a name for the action of closing a channel or what is it or how it relates to closing a channel and receiving funds (in a bech32 address, ultimately??).
3. As far as I read, when we open a channel, we implicitly have to fund it. Those funds will remain in a multi-signature address. (a) Is this accurate? (b)If so, can we see that multi-signature address contents in a Blockchain explorer like Blockchair, for instance? (c) I assume that the Lightning Network protocol implicitly controls the PKs of this multi-signature address an that when both parties agree in closing the channel, the software automatically "inserts" both PKs so that the channel can be closed or each one of us needs to provide it manually? (d) Can we see that multi-signature address or is it somehow embedded in the software one is using?
4. An invoice is something we can create separately and then present to any channel/node so that we can send/receive a payment or is it something that is also inherent to opening/closing a channel?

Well, I think most of these questions would be answered by experimenting, but I'm still not confident to try it on my own.

Hope I can get some clarification. I have already read a few links I was given in another thread. FAQ and a kind of an Intro to the LN with some basic concepts.

[jackg]

1.(a) Do I need any address to receive payments? If we don't need an address, (b) why does c-lightning software has a command to get a new address? If we need one, (c) can it be a bech32?

This'll be specific to the node but generally:
Addresses are for receiving funds from the main chain - so it can still act like a regular bitcoin wallet.
Invoices are for lightning transactions.

2. I'm still not sure if invoices are just a name for the action of closing a channel or what is it or how it relates to closing a channel and receiving funds (in a bech32 address, ultimately??).

Invoices on their own are a bit like sending a parcel.

It includes the address + what you want to be sent in a string of characters. They don't have a bearing on channel closures but if someone signs to consent to sending those funds they're then transferred by a series of contracts to their final state that satisfies the invoice.

3. As far as I read, when we open a channel, we implicitly have to fund it. Those funds will remain in a multi-signature address. (a) Is this accurate? (b)If so, can we see that multi-signature address contents in a Blockchain explorer like Blockchair, for instance? (c) I assume that the Lightning Network protocol implicitly controls the PKs of this multi-signature address an that when both parties agree in closing the channel, the software automatically "inserts" both PKs so that the channel can be closed or each one of us needs to provide it manually? (d) Can we see that multi-signature address or is it somehow embedded in the software one is using?

Yes it is possible to see the address on the chain, if you've opened a channel just look at either the funding transaction or search the address with funds in it on blockchain.com or btc.com and you'll see your funds are transferred there.

YOU and your node control the PKs. A thing is sent called a "Commitment transaction" CT which allows your channel to have a single state you both agree on.

If the other node goes offline, and I've had that happen, you merely broadcast your last commitment transaction and your funds are restored back to your wallet.

4. An invoice is something we can create separately and then present to any channel/node so that we can send/receive a payment or is it something that is also inherent to opening/closing a channel?

This is what commitment transactions are for (opening and closing channels). Invoices only tell someone how much you want them to send, where you want them to send it and how long they have to send it.

[darkv0rt3x]

Thanks a lot jackg, for your reply.

One more thing. I can't wait to start experimenting with my node, but for 5 questions I get the answers, a few more questions arise.

Can I just create an invoice for the sake of experimenting, without opening a channel?

[jackg]

Can I just create an invoice for the sake of experimenting, without opening a channel?

No not on mainnet anyway.

I'm sure there's some testnet faucet that gives free bitcoin if you wanted to test out invoices there though (preloading a testnet channel).

[darkv0rt3x]

Hello.

I was trying to find some site like LNBig to open a channel with me so that I have some inbound liquidity but their site always says there there are no free funds to open any channels. I also tried to request, by email, an inbound channel to PeerNode site. But after 3 days I have no answer from them.

Where else can I find someone to open a channel with me so that I can receive satoshis via my c-lightning node? I have Bluewallet installed in my mobile phone and I know it is not compatible with c-lightning, so I have installed Spark wallet in my desktop. So, now, I want to send the sats from Bluewallet to my Sparkwallet and then, eventually, send the sats to BTC address I own.

[jackg]

Hello.

I was trying to find some site like LNBig to open a channel with me so that I have some inbound liquidity but their site always says there there are no free funds to open any channels. I also tried to request, by email, an inbound channel to PeerNode site. But after 3 days I have no answer from them.

Where else can I find someone to open a channel with me so that I can receive satoshis via my c-lightning node? I have Bluewallet installed in my mobile phone and I know it is not compatible with c-lightning, so I have installed Spark wallet in my desktop. So, now, I want to send the sats from Bluewallet to my Sparkwallet and then, eventually, send the sats to BTC address I own.

I created a list of forum users here: https://bitcointalk.org/index.php?topic=5266907.msg54940969#msg54940969

You could also use a site like this to find more: https://explorer.acinq.co/

[darkv0rt3x]

@jackg, thank you. That will be useful when and only when I fix what I think it's some connection issues with my node. I have created a thread about it but still waiting on some help.

Thanks

[Wind_FURY]

What's the technical problem with Lightning? What is making the exchanges hesitant from integrating it to complement their service? Plus are there business development people behind Lightning Labs to handle onboarding the exchanges and other institutions?

[jackg]

What's the technical problem with Lightning? What is making the exchanges hesitant from integrating it to complement their service? Plus are there business development people behind Lightning Labs to handle onboarding the exchanges and other institutions?

I think the main and realistic problem currently is that it isn't fully developed and hasn't had the time to prove its security.

There are a bunch of reasons different companies don't get involved, they'll be judged for everything.

On top of that it took quite a while for segwit to be adopted and this protocol requires companies to host a channel/watchtower in one location and send all their outputs out through that.
Not to mention, as soon as an exchange starts accepting the lightning network, therell be a lot of people trying to use it. And we do have more nodes than bitcoin mainnet (afaik) but each node is kinda like a miner and we probably don't have more devices signalling for the security of the ln (not that we need to get too close to that).

Exchanges work based on competition I think binance are investing in lightning research at least, so the other major large players will be doing the same...

[DaveF]

What's the technical problem with Lightning? What is making the exchanges hesitant from integrating it to complement their service? Plus are there business development people behind Lightning Labs to handle onboarding the exchanges and other institutions?

Aside from what @jackg said and classical problem such as "why bother upgrade if it's not broken" or "the code is poorly written/have no proper documentation", there are few specific concern (both technical and non-technical) such as :
1. What happen when a channel is closed, but the used on-chain transaction fee is low and there are many pending transaction on mempool?
2. Most LN implementation (e.g. LND and c-lightning) are still on beta, which isn't acceptable for most exchange and writing their own LN implementation isn't an option for smaller exchange.
3. Educating customer who don't know their LN wallet doesn't accept incoming transaction

I actually made a comment about this in the gambling section, because I asked why they accepted lightning for deposits but not withdrawals. They replied working on it but difficult.

I actually see their point. If you go to deposit and it fails you still have your BTC and you can try to figure out what is wrong.
If they try to send you BTC and it fails, they have to figure out what is wrong on their end, or your channel, etc. I have played at some casinos that have lightning deposit and withdraw and when the withdraw failed it was a real pain to figure out the issue. Turned out to be one of my channels but 1st thing I did was ask them what they were doing wrong.....
-Dave

For trivial amounts of money it's not a big deal if someone has to wait for everyone to figure out what is wrong, for larger amounts it is a big deal.
But.....
For trivial amounts it's not worth the time and effort to setup lightning for them. For larger amounts I could see it being a support nightmare.
How many posts here do you think we would see with people complaining that they were not getting 0.025BTC funds from exchange XYZ while the exchange is trying to explain the largest channel they have open is .0245BTC

-Dave

[PrimeNumber7]

What's the technical problem with Lightning? What is making the exchanges hesitant from integrating it to complement their service? Plus are there business development people behind Lightning Labs to handle onboarding the exchanges and other institutions?

Aside from what @jackg said and classical problem such as "why bother upgrade if it's not broken" or "the code is poorly written/have no proper documentation", there are few specific concern (both technical and non-technical) such as :
1. What happen when a channel is closed, but the used on-chain transaction fee is low and there are many pending transaction on mempool?
2. Most LN implementation (e.g. LND and c-lightning) are still on beta, which isn't acceptable for most exchange and writing their own LN implementation isn't an option for smaller exchange.
3. Educating customer who don't know their LN wallet doesn't accept incoming transaction

I actually made a comment about this in the gambling section, because I asked why they accepted lightning for deposits but not withdrawals. They replied working on it but difficult.

I actually see their point. If you go to deposit and it fails you still have your BTC and you can try to figure out what is wrong.
If they try to send you BTC and it fails, they have to figure out what is wrong on their end, or your channel, etc. I have played at some casinos that have lightning deposit and withdraw and when the withdraw failed it was a real pain to figure out the issue. Turned out to be one of my channels but 1st thing I did was ask them what they were doing wrong.....
-Dave

For trivial amounts of money it's not a big deal if someone has to wait for everyone to figure out what is wrong, for larger amounts it is a big deal.
But.....
For trivial amounts it's not worth the time and effort to setup lightning for them. For larger amounts I could see it being a support nightmare.
How many posts here do you think we would see with people complaining that they were not getting 0.025BTC funds from exchange XYZ while the exchange is trying to explain the largest channel they have open is .0245BTC

-Dave

Businesses that accept LN today often advertise the maximum they can receive via LN. I don't see any reason why businesses wouldn't be able to advertise the max they can send via LN.
It would probably be a good idea to have LN clients be able to split up invoices so a payment can go through multiple routes, and the transaction will only go through if all invoices are paid.

For example, due to the various channel states between Bob and Allice, the maximum amount Bob can send to Allice is 0.05, even though Allice has >0.1 inbound capacity and Bob has >0.1 outbound capacity. Allice could send an invoice to Bob for 0.06 that Bob pays that gets split into two (or more) invoices.

[LoyceV]

How many posts here do you think we would see with people complaining that they were not getting 0.025BTC funds from exchange XYZ while the exchange is trying to explain the largest channel they have open is .0245BTC

If I can trust exchange XYZ I don't have to withdraw my $280 in LN funds, I'll just leave it there and pay services directly. That way funds move from one well-connected node to another one, and I don't have any problems with incoming capacity.

[Rath_]

It would probably be a good idea to have LN clients be able to split up invoices so a payment can go through multiple routes, and the transaction will only go through if all invoices are paid.

LND, c-lightning and Eclair already support multipart payments which allow to pay a single invoice through multiple routes without any additional effort needed from the user.

[DaveF]

For trivial amounts of money it's not a big deal if someone has to wait for everyone to figure out what is wrong, for larger amounts it is a big deal.
But.....
For trivial amounts it's not worth the time and effort to setup lightning for them. For larger amounts I could see it being a support nightmare.
How many posts here do you think we would see with people complaining that they were not getting 0.025BTC funds from exchange XYZ while the exchange is trying to explain the largest channel they have open is .0245BTC

-Dave

Businesses that accept LN today often advertise the maximum they can receive via LN. I don't see any reason why businesses wouldn't be able to advertise the max they can send via LN.

It's not what *they* can send it's what *the customer* can receive.



Look I have 0 that's zero, nothing, nada, zip inbound or outbound available. I just spun that node up.
But I can create a payment request and send it to an exchange, or anyone.
Not going to work however. So, yeah that's the issue.

Used RTL to make the point because it's easier to see, but can do the same from the CLI and get the same result.

-Dave

[PrimeNumber7]

For trivial amounts of money it's not a big deal if someone has to wait for everyone to figure out what is wrong, for larger amounts it is a big deal.
But.....
For trivial amounts it's not worth the time and effort to setup lightning for them. For larger amounts I could see it being a support nightmare.
How many posts here do you think we would see with people complaining that they were not getting 0.025BTC funds from exchange XYZ while the exchange is trying to explain the largest channel they have open is .0245BTC

-Dave

Businesses that accept LN today often advertise the maximum they can receive via LN. I don't see any reason why businesses wouldn't be able to advertise the max they can send via LN.

It's not what *they* can send it's what *the customer* can receive.

[img ]https://i.imgur.com/pZIR5jgl.jpg[/img]

Look I have 0 that's zero, nothing, nada, zip inbound or outbound available. I just spun that node up.
But I can create a payment request and send it to an exchange, or anyone.
Not going to work however. So, yeah that's the issue.

Used RTL to make the point because it's easier to see, but can do the same from the CLI and get the same result.

-Dave

Ahh, I see your point. If a person has open channels with insufficient inbound capacity, the customer not understanding their inbound capacity limit may be an issue of insufficient/inadequate documentation that can be read/understood by the 'average' non-technical user, or error messages that are not specific enough.

If you were to send that invoice to a business, the business should (automatically) be able to tell you what is preventing them from paying the invoice, in your case insufficient inbound capacity.

[Wind_FURY]

OK, then before we could start to lok for some actual consumer-facing apps for Lightning, there has to be some effort made to onboard the exchanges to grow the infrastructure, and increase/stablilize liquidity/capacity. When will it be? Who should the people responsible be for Lightning's business development?

[Wind_FURY]

Who should the people responsible be for Lightning's business development?

No one, after all Bitcoin community (and some open source) is powered by volunteer.

I know. I was pointing out companies like Lightning Labs, as they are "the company", or one of the companies behind Lightning Network development. Plus Blockstream too. What happened to Blockstream and Lightning?

[Carlton Banks]

Who should the people responsible be for Lightning's business development?

No one, after all Bitcoin community (and some open source) is powered by volunteer.

or "everyone"

those who refuse to provide incoming liquidity to others are not helping the network (including those who charge a fee to do so, but that's my opinion and their prerogative)

we can all help the situation by identifying nodes with low or no incoming liquidity, and providing it to them by opening a channel. I realize that there's potentially more fees to be earned opening channels to nodes with higher routing throughput, but ultimately, a better connected network is stronger (and more profitable in all aspects) than a centralized network. There will doubtless be a limit to how may channels it's useful for a single routing node to have, although I am unsure what that limit is (it's likely related to the amount of traffic on the network considered over a long timeframe, as well as how much BTC a node has to put into the network).