public inbox for bitcoindev@googlegroups.com
 help / color / mirror / Atom feed
From: Matthew Mitchell <matthewmitchell@godofgod.co.uk>
To: Luke-Jr <luke@dashjr.org>,
	"bitcoin-development@lists.sourceforge.net"
	<bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Segmented Block Relaying BIP draft.
Date: Mon, 10 Sep 2012 20:34:10 +0100	[thread overview]
Message-ID: <239CFE18-302F-47F1-8686-67297FDDFB3C@godofgod.co.uk> (raw)
In-Reply-To: <201209101859.05009.luke@dashjr.org>

[-- Attachment #1: Type: text/plain, Size: 2400 bytes --]

Do you mean getdata? Here is the reason for the 6 new messages:

getseginv,seginv - These are for learning about what segments of a block a node has. Else you could remove these messages and simply have nodes advertise blocks via inventory messages. In this case nodes would have to wait until they had fully received a block before relaying anything. No longer is there a benefit with nodes being able to relay segments of blocks before they have received the entire block.

gettreelevel,treelevel - These are to received a level of the merle tree. Instead you might use get data but gettreelevel is more compact than get data and is clearly differentiates itself as part of the new protocol. Perhaps these messages could include the block headers alongside the hashes and you could request many at once like with the getheaders message? If you skip these messages, then you could verify the transactions at the end but there would be problems when peers give bad segments where data would need to be downloaded again.

getsegment,segment - These are clearly important to request and receive segments for the blocks. These allows for nodes to download arbitrary segments of blocks. The optimum number of segments could be calculated by node software using measurements of download speeds and latency times, the number of connections and how likely redundancy is to occur. If a node is up-to-date and likely has many of the transactions in blocks, it can start asking for the deepest merle level (tx hashes) and ask nodes for segments, avoiding transactions it already has.

I'll get around to doing measurements myself sometime to estimate the benefit of this proposal. It will certainly be beneficial when block sizes reach some size but not much is really known except what can be assumed/guessed.

I should also mention the bitcointalk topic here: https://bitcointalk.org/index.php?topic=103295.0

On 10 Sep 2012, at 19:59, "Luke-Jr" <luke@dashjr.org> wrote:
> 
> Most of the problem with block propagation lies in implementation, not 
> protocol... Distributing missing transaction on an as-needed basis is a 
> possible improvement at the protocol level, but there hasn't (AFAIK) been any 
> research into whether the little benefit outweighs the cost yet. In any case, 
> I don't see why 6 new messages are needed instead of simply adding a single 
> new type to getinv?


[-- Attachment #2: Type: text/html, Size: 5522 bytes --]

  reply	other threads:[~2012-09-10 19:34 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-10 15:07 [Bitcoin-development] Segmented Block Relaying BIP draft Matthew Mitchell
2012-09-10 15:14 ` Gregory Maxwell
2012-09-10 16:29   ` Matt Corallo
2012-09-10 18:59 ` Luke-Jr
2012-09-10 19:34   ` Matthew Mitchell [this message]
2012-09-10 19:53     ` Matt Corallo
2012-09-10 20:00       ` Gregory Maxwell
2012-09-11 19:07 Matthew Mitchell
2012-09-11 19:42 ` Gregory Maxwell
2012-09-11 21:48   ` Matthew Mitchell
2012-09-11 23:22     ` Gregory Maxwell
2012-09-13  8:42       ` Mike Hearn
2012-09-13 14:05         ` Matthew Mitchell
2012-09-13 15:16           ` Gregory Maxwell
     [not found]             ` <2B95CF41-4304-4D2A-9ABF-198D97B7449B@godofgod.co.uk>
2012-09-13 15:46               ` Matthew Mitchell
     [not found]               ` <CAAS2fgQi8QFwU2M=wLiDodt3SmO48vUV5Sp3YCb1OmGJ5m=E7Q@mail.gmail.com>
2012-09-13 17:49                 ` Matthew Mitchell
2012-09-13 18:59                   ` Pieter Wuille
2012-09-13 20:24                     ` Matthew Mitchell

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=239CFE18-302F-47F1-8686-67297FDDFB3C@godofgod.co.uk \
    --to=matthewmitchell@godofgod.co.uk \
    --cc=bitcoin-development@lists.sourceforge.net \
    --cc=luke@dashjr.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox