core-lightning/doc/lightning-getroute.7

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.\"     Title: lightning-getroute
.\"    Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: 03/01/2019
.\"    Manual: \ \&
.\"    Source: \ \&
.\"  Language: English
.\"
.TH "LIGHTNING\-GETROUTE" "7" "03/01/2019" "\ \&" "\ \&"
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.SH "NAME"
lightning-getroute \- Command for routing a payment (low\-level)\&.
.SH "SYNOPSIS"
.sp
\fBgetroute\fR \fIid\fR \fImsatoshi\fR \fIriskfactor\fR [\fIcltv\fR] [\fIfromid\fR] [\fIfuzzpercent\fR] [\fIexclude\fR] [\fImaxhops\fR]
.SH "DESCRIPTION"
.sp
The \fBgetroute\fR RPC command attempts to find the best route for the payment of \fImsatoshi\fR to lightning node \fIid\fR, such that the payment will arrive at \fIid\fR with \fIcltv\fR\-blocks to spare (default 9)\&.
.sp
\fImsatoshi\fR is in millisatoshi precision; it can be a whole number, or a whole number ending in \fImsat\fR or \fIsat\fR, or a number with three decimal places ending in \fIsat\fR, or a number with 1 to 11 decimal places ending in \fIbtc\fR\&.
.sp
There are two considerations for how good a route is: how low the fees are, and how long your payment will get stuck in a delayed output if a node goes down during the process\&. The \fIriskfactor\fR floating\-point field controls this tradeoff; it is the annual cost of your funds being stuck (as a percentage)\&.
.sp
For example, if you thought the convenience of keeping your funds liquid (not stuck) was worth 20% per annum interest, \fIriskfactor\fR would be 20\&.
.sp
If you didn\(cqt care about risk, \fIriskfactor\fR would be zero\&.
.sp
\fIfromid\fR is the node to start the route from: default is this node\&.
.sp
The \fIfuzzpercent\fR is a positive floating\-point number, representing a percentage of the actual fee\&. The \fIfuzzpercent\fR is used to distort computed fees along each channel, to provide some randomization to the route generated\&. 0\&.0 means the exact fee of that channel is used, while 100\&.0 means the fee used might be from 0 to twice the actual fee\&. The default is 5\&.0, or up to 5% fee distortion\&.
.sp
\fIexclude\fR is a JSON array of short\-channel\-id/direction (e\&.g\&. [ "564334x877x1/0", "564195x1292x0/1" ]) which should be excluded from consideration for routing\&. The default is not to exclude any channels\&.
.sp
\fImaxhops\fR is the maximum number of channels to return; default is 20\&.
.SH "RISKFACTOR EFFECT ON ROUTING"
.sp
The risk factor is treated as if it were an additional fee on the route, for the purposes of comparing routes\&.
.sp
The formula used is the following approximation:
.sp
.if n \{\
.RS 4
.\}
.nf
risk\-fee = amount x blocks\-timeout x per\-block\-cost
.fi
.if n \{\
.RE
.\}
.sp
We are given a \fIriskfactor\fR expressed as a percentage\&. There are 52596 blocks per year, thus \fIper\-block\-cost\fR is \fIriskfactor\fR divided by 5,259,600\&.
.sp
The final result is:
.sp
.if n \{\
.RS 4
.\}
.nf
risk\-fee = amount x blocks\-timeout x riskfactor / 5259600
.fi
.if n \{\
.RE
.\}
.sp
Here are the risk fees in millisatoshis, using various parameters\&. I assume a channel charges the default of 1000 millisatoshis plus 1 part\-per\-million\&. Common to_self_delay values on the network at 14 and 144 blocks\&.
.TS
allbox tab(:);
ltB ltB ltB ltB ltB.
T{
Amount (msat)
T}:T{
Riskfactor
T}:T{
Delay
T}:T{
Risk Fee
T}:T{
Route fee
T}
.T&
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt
lt lt lt lt lt.
T{
.sp
10,000
T}:T{
.sp
1
T}:T{
.sp
14
T}:T{
.sp
0
T}:T{
.sp
1001
T}
T{
.sp
10,000
T}:T{
.sp
10
T}:T{
.sp
14
T}:T{
.sp
0
T}:T{
.sp
1001
T}
T{
.sp
10,000
T}:T{
.sp
100
T}:T{
.sp
14
T}:T{
.sp
2
T}:T{
.sp
1001
T}
T{
.sp
10,000
T}:T{
.sp
1000
T}:T{
.sp
14
T}:T{
.sp
26
T}:T{
.sp
1001
T}
T{
.sp
1,000,000
T}:T{
.sp
1
T}:T{
.sp
14
T}:T{
.sp
2
T}:T{
.sp
1001
T}
T{
.sp
1,000,000
T}:T{
.sp
10
T}:T{
.sp
14
T}:T{
.sp
26
T}:T{
.sp
1001
T}
T{
.sp
1,000,000
T}:T{
.sp
100
T}:T{
.sp
14
T}:T{
.sp
266
T}:T{
.sp
1001
T}
T{
.sp
1,000,000
T}:T{
.sp
1000
T}:T{
.sp
14
T}:T{
.sp
2661
T}:T{
.sp
1001
T}
T{
.sp
100,000,000
T}:T{
.sp
1
T}:T{
.sp
14
T}:T{
.sp
266
T}:T{
.sp
1100
T}
T{
.sp
100,000,000
T}:T{
.sp
10
T}:T{
.sp
14
T}:T{
.sp
2661
T}:T{
.sp
1100
T}
T{
.sp
100,000,000
T}:T{
.sp
100
T}:T{
.sp
14
T}:T{
.sp
26617
T}:T{
.sp
1100
T}
T{
.sp
100,000,000
T}:T{
.sp
1000
T}:T{
.sp
14
T}:T{
.sp
266179
T}:T{
.sp
1100
T}
T{
.sp
10,000
T}:T{
.sp
1
T}:T{
.sp
144
T}:T{
.sp
0
T}:T{
.sp
1001
T}
T{
.sp
10,000
T}:T{
.sp
10
T}:T{
.sp
144
T}:T{
.sp
2
T}:T{
.sp
1001
T}
T{
.sp
10,000
T}:T{
.sp
100
T}:T{
.sp
144
T}:T{
.sp
27
T}:T{
.sp
1001
T}
T{
.sp
10,000
T}:T{
.sp
1000
T}:T{
.sp
144
T}:T{
.sp
273
T}:T{
.sp
1001
T}
T{
.sp
1,000,000
T}:T{
.sp
1
T}:T{
.sp
144
T}:T{
.sp
27
T}:T{
.sp
1001
T}
T{
.sp
1,000,000
T}:T{
.sp
10
T}:T{
.sp
144
T}:T{
.sp
273
T}:T{
.sp
1001
T}
T{
.sp
1,000,000
T}:T{
.sp
100
T}:T{
.sp
144
T}:T{
.sp
2737
T}:T{
.sp
1001
T}
T{
.sp
1,000,000
T}:T{
.sp
1000
T}:T{
.sp
144
T}:T{
.sp
27378
T}:T{
.sp
1001
T}
T{
.sp
100,000,000
T}:T{
.sp
1
T}:T{
.sp
144
T}:T{
.sp
2737
T}:T{
.sp
1100
T}
T{
.sp
100,000,000
T}:T{
.sp
10
T}:T{
.sp
144
T}:T{
.sp
27378
T}:T{
.sp
1100
T}
T{
.sp
100,000,000
T}:T{
.sp
100
T}:T{
.sp
144
T}:T{
.sp
273785
T}:T{
.sp
1100
T}
T{
.sp
100,000,000
T}:T{
.sp
1000
T}:T{
.sp
144
T}:T{
.sp
2737850
T}:T{
.sp
1100
T}
.TE
.sp 1
.SH "RECOMMENDED RISKFACTOR VALUES"
.sp
The default \fIfuzz\fR factor is 5%, so as you can see from the table above, that tends to overwhelm the effect of \fIriskfactor\fR less than about 5\&.
.sp
1 is a conservative value for a stable lightning network with very few failures\&.
.sp
1000 is an aggressive value for trying to minimize timeouts at all costs\&.
.sp
The default for lightning\-pay(7) is 10, which starts to become a major factor for larger amounts, and is basically ignored for tiny ones\&.
.SH "RETURN VALUE"
.sp
On success, a "route" array is returned\&. Each array element contains \fIid\fR (the node being routed through), \fImsatoshi\fR (the millisatoshis sent), \fIamount_msat\fR (the same, with \fImsat\fR appended), and \fIdelay\fR (the number of blocks to timeout at this node)\&.
.sp
The final \fIid\fR will be the destination \fIid\fR given in the input\&. The difference between the first \fImsatoshi\fR minus the \fImsatoshi\fR given in the input is the fee\&. The first \fIdelay\fR is the very worst case timeout for the payment failure, in blocks\&.
.SH "AUTHOR"
.sp
Rusty Russell <rusty@rustcorp\&.com\&.au> is mainly responsible\&.
.SH "SEE ALSO"
.sp
lightning\-pay(7), lightning\-sendpay(7)\&.
.SH "RESOURCES"
.sp
Main web site: https://github\&.com/ElementsProject/lightning