Re: [Bitcoin-development] [ANN] High-speed Bitcoin Relay Network

[Matt Corallo <bitcoin-list@bluematt.me>]

For those who have been using this to get faster relays to/from the
network, you may have noticed some instability recently. This is because
the nodes were all being upgraded to use some new relaying code which
should cut down on duplicate transaction relaying in blocks, improving
relay speed within the network and to nodes which run new clients which
use the same relaying technique. Essentially instead of relaying entire
blocks, nodes keep a rolling window of recently-seen transactions and
skip those when relaying blocks.

You can find a simple client which connects to a local bitcoind and a
relay node at http://bitcoin.ninja/RelayNodeClient.jar and the source
for the whole thing at https://github.com/TheBlueMatt/RelayNode.

Matt

On 11/06/13 05:50, Matt Corallo wrote:
> Recently, there has been a reasonable amount of discussion about the
> continued fragility of the public Bitcoin network on IRC and elsewhere
> (1). To this extent, I'm organizing a system of peering between nodes in
> the network by creating a system of high-speed relay nodes for miners
> and merchants/exchanges. This system will a) act as a fallback in the
> case that the public Bitcoin network encounters issues and b) decrease
> block propagation times between miners.
> It is NOT designed to in any way replace or decrease the need for the
> public Bitcoin P2P network. It is NOT any kind of attempt at
> centralization, and I still encourage interested parties to establish
> their own private peering agreements with large miners as needed.
> 
> Currently the network consists of one specially-designed relay node, but
> I hope to bring more online in the coming days.
> 
> This network is open to everyone via a few public relay nodes, but also
> will have nodes which are made available only to large miners and
> merchants/exchanges to mitigate the ability of malicious parties to DoS
> the network.
> 
> To peer with the public relay nodes, simply select the closest region
> out of us-west (West Coast US), us-east (East Coast US), eu (Western
> Europe), au (Australia), or jpy (Japan) and add
> public.REGION.relay.mattcorallo.com to your addnode list. Note that
> since all of the relay nodes will relay between each other, you gain no
> latency advantage by peering with more than the closest node to you (and
> currently all the regions map to one node, so there they're redundant
> anyway).
> 
> For each relay node, you can connect to either port 8334 or 8335.
> Connecting on port 8334 will relay only blocks, and port 8335 will relay
> both blocks and transactions. The relay nodes will request any
> transactions which appear in your invs no matter which port you connect to.
> 
> Relay node details:
>  * The relay nodes do some data verification to prevent DoS, but in
> order to keep relay fast, they do not fully verify the data they are
> relaying, thus YOU SHOULD NEVER mine a block building on top of a
> relayed block without fully checking it with your own bitcoin validator
> (as you would any other block relayed from the P2P network).
>  * The relay nodes do not follow the standard inv-getdata-tx/block flow,
> but instead relay transactions/blocks immediately after they have done
> their cursory verification. They do keep some track of whether or not
> your nodes claim to have seen the transactions/blocks before relaying,
> but you may see transactions/blocks being sent which you already have
> and have not requested, if this is a problem for you due to bandwith
> issues, you should reconsider your bandwith constraints and/or are
> peering with too many nodes.
>  * The relay nodes will all relay among themselves very quickly, so
> there is no advantage to peering with as many relay nodes as you can
> find, in fact, the increased incoming bandwidth during block relay
> spikes may result in higher latency for your nodes.
>  * The relay nodes are NOT designed to ensure that you never miss data,
> and may fail to relay some transactions. Additionally, because the relay
> nodes do not respond to standard getdata requests, if you miss a relay
> and then reconnect, that data will not be sent again by the relay nodes.
> The relay nodes are NOT a replacement for having peers on the standard
> P2P network, they are only there to augment the existing P2P network.
> 
> If you are a merchant/exchange/large miner/other important node operator
> and wish to gain access to additional domain names which map to relay
> nodes with fewer peers, please fill out the form at
> https://docs.google.com/forms/d/1UL82QdcXXEhZwSHJAK04Sk_cWg4zLOu8a216nO7Mt8c/viewform
> 
> You can find the source for the relay nodes at
> https://github.com/TheBlueMatt/RelayNode
> 
> If you have any comments/concerns/suggestions, please do not hesitate to
> email bitcoin-peering@mattcorallo.com
> 
> Thanks,
> Matt
> 
> 
> (1) There has been extended discussion on #bitcoin-wizards as well as
> #bitcoin-dev of the very small number of active, listening nodes.
> Additionally, because many of those nodes are versions prior to 0.8.4,
> it seems very likely that maliciously creating network splits or at
> least drastically reducing the number of peers for most nodes would not
> be particularly challenging in the current network. Also,
> http://www.tik.ee.ethz.ch/file/49318d3f56c1d525aabf7fda78b23fc0/P2P2013_041.pdf
> noted that they were able to single-handledly decrease the network-wide
> orphan rate by around 50% by improving network peering. Finally, you've
> all seen the recent discussion on malicious mining algorithms. Though
> those are not entirely prevented by reducing block propagation times,
> they can be significantly limited compared to the current, rather
> disjoint, network.
> 
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