One possible solution that wallets could adopt when blocks fill up, would be to abandon the p2p network for transaction propagation altogether, and instead work directly with a handful of the largest miners and pools to get transactions into blocks. The miners could auction off space in their blocks with the guarantee that they will be included in the order accepted. We&#39;d lose the peer-to-peer nature of sending transactions for a federated service operator style model, but avoid the problem of unpredictable transaction failure. Also, unlike replace-by-fee, this would allow for a send-and-forget usage pattern, as well as known up-front fees. Something like this is certainly what I imagine the large hosted wallet companies will end up moving to.<div><br></div><div>Aaron</div><div><span></span><br>On Thursday, June 11, 2015, Mike Hearn &lt;<a href="mailto:mike@plan99.net">mike@plan99.net</a>&gt; wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span>&gt; Re: &quot;dropped in an unpredictable way&quot; - transactions would be dropped<br>
&gt; lowest fee/KB first, a completely predictable way.<br>
<br>
</span>Quite agreed.  </blockquote><div><br></div><div>No, Aaron is correct. It&#39;s unpredictable from the perspective of the user sending the transaction, and as they are the ones picking the fees, that is what matters.</div></div></div></div>
</blockquote></div><br><br>-- <br><div dir="ltr"><div><div dir="ltr"><div><br>Aaron Voisine</div><div>co-founder and CEO<br><a href="http://breadwallet.com" target="_blank">breadwallet.com</a></div></div></div></div><br>