Yeah, sure. > How much bandwidth is consumed by redundant tx INVs currently? Currently, for an average public-IP node all INVs consume 0.05 Mbps or 540 megabytes per day. This number is based on current ratio public-IP nodes:private-IP nodes and transaction rate. This number is a sum of both incoming and outgoing aspects. Thus redundant INV’s on average consume 0.044 Mbps or 475 megabytes per day.
> What is this as a % of overall bandwidth usage? This is hard to estimate because overall bandwidth includes helping other nodes to bootstrap from scratch. If we don’t consider this aspect, my very rough estimate, and a short experiment shows that INV’s are around 50% of overall bandwidth (it also depends on different factors like your hardware comparing to other public-IP nodes). I’m going to double-check this number soon. > How would filtering txs through N=2 links affect network propagation? Yes, network propagation for a new protocol definitely worth measuring. I’m going to look at it in the near future. > Do you propose setting filters on inbound peers as well? This is a good question. I think some filter may be applied to inbound connections. Theoretically, a symmetrical filter does not make much sense — it might be eventually the same filter for all of the connections except first 8 outgoing ones, so it’s better to use independent filters. However, I’m not entirely sure it is needed. Filters on inbound peers will reduce a download aspect. It might be much less critical than upload (if we assume that private-IP nodes hear about transactions later because those have much fewer connections). I think this question needs another experiment. On Apr 3, 2018, 10:45 AM -0700, Jim Posen <jim.po...@gmail.com>, wrote: > Hey. This idea sounds quite interesting. It'd be helpful to see some more > numbers to evaluate it. > > - How much bandwidth is consumed by redundant tx INVs currently? What is this > as a % of overall bandwidth usage? > - How would filtering txs through N=2 links affect network propagation? This > probably requires simulation to determine. > - Do you propose setting filters on inbound peers as well? > > > On Mon, Apr 2, 2018 at 3:18 PM, Gleb Naumenko via bitcoin-dev > > <bitcoin-dev@lists.linuxfoundation.org> wrote: > > > Hi all, > > > I have a couple of ideas regarding transaction relay protocol and wanted > > > to share it with and probably get some feedback. > > > > > > I did some emulation and simulation and found out that around 90% of INV > > > messages sent by public-IP nodes are idle (duplicate), obviously because > > > each node creates 8 connections. I also realized that sending INV > > > messages is a significant part of the overall bandwidth consumed by a > > > public-IP node. At a larger scale, this will result in people not able to > > > run a public-IP node. > > > > > > My idea is in some sense similar to BIP37 but applied to public-IP nodes. > > > Here I want to emphasize that all the nodes will still receive *all* of > > > the transactions. A new protocol should also keep the same zero-trust, > > > robustness, decentralization guarantees and latency. > > > > > > Idea: while joining the network, a new node agrees on some filter with > > > each of 8 nodes it connects to. So that NewNode <-> Node_A will be used > > > to relay only a subset of transactions, NewNode <-> Node_B for another > > > subset. This will significantly decrease the redundancy. > > > > > > To keep the guarantees, I would keep some redundancy (for example, each > > > transaction INV is sent over 2 links). > > > > > > To make it robust to attacks, I have 2 extensions in my mind: > > > 1. Set reconciliation (for a subset of transactions) with *other* nodes. > > > Getting a bloom filter of a subset of the mempool transactions from > > > Node_B may help to figure out whether Node_A is malicious, very slow, etc. > > > 2. Rotating the filters every N minutes (N < 10) > > > > > > I can see some issues with latency here, but I believe this problem has a > > > solution. > > > > > > Feedback is appreciated! > > > > > > If you want to look at a draft of the proposal — please let me know. > > > If there were any similar ideas — please let me know. > > > > > > Best, > > > Gleb > > > > > > > > > _______________________________________________ > > > bitcoin-dev mailing list > > > bitcoin-dev@lists.linuxfoundation.org > > > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > > > >
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