user81940: Currently and as defined by BOLT 07 on the Lightning Network, the fees for forwarding an HTLC of amount amount_to_forward are computed as:
fee_base_msat +  amount_to_forward * fee_proportional_millionths / 1000000

I am wondering why the fee_base_msat was actually included and which concrete problem it solved that could not be solved if the fee_base_msat were dropped?

user90217: It was added as a compromise against more complicated ideas, actually. Base plus percentage is a pretty standard fee structure, so I went with it.
If I'd been more familiar with the finance world, it would have been expressed in basis points, though, not ppm.

81940: <p>Currently and <a href="https://github.com/lightningnetwork/lightning-rfc/blob/master/07-routing-gossip.md#htlc-fees" rel="nofollow noreferrer">as defined by BOLT 07</a> on the Lightning Network, the fees for forwarding an HTLC of amount <code>amount_to_forward</code> are computed as:</p>
<pre><code>fee_base_msat +  amount_to_forward * fee_proportional_millionths / 1000000
</code></pre>
<p>I am wondering why the <code>fee_base_msat</code> was actually included and which concrete problem it solved that could not be solved if the <code>fee_base_msat</code> were dropped?</p>
 90217: <p>It was added as a compromise against <em>more complicated</em> ideas, actually. Base plus percentage is a pretty standard fee structure, so I went with it.</p>
<p>If I'd been more familiar with the finance world, it would have been expressed in basis points, though, not ppm.</p>
