- What is Xpedited Forwarding
Xpedited Forwarding is a decentralised rapid block propagation system designed to replace the centralised Relay Network. Anyone can participate in or easily setup their own Xpedited Network.
The forwarding mechanism while simple to understand uses several enhancements to speed the delivery of newly mined blocks throughout the world and most importantly to other miners. Essentially when one participates in the network, as soon as a new block is found, an Xthin-format block is forwarded to every node you are connected to that has requested expedited forwarding. When they receive the Xthin-format block, the header is quickly checked to make sure it is valid (and of appropriate difficulty) and then forwarded to the next set of nodes and so on.
It's important to note that the block is verified and accepted only after being forwarded. And the normal 3-phase conversation (INV, GET, response) is reduced to a single send. This allows for a much faster propagation through the network.
- Setting up an Xpedited connection
Xpedited connections can only be set up by the node that will be receiving the Xpedited data.
There are two ways to setup Xpedited connections. First, you can use the expedited command in the bitcoin-cli or RPC calls to
request expedited service from a particular node (use "addnode onetry" to make sure you are connected first). However, if
your connection to this node is dropped, or your node is reset, expedited service will not be re-established until you run the
expedited command again.
The recommended method is to add entries in your bitcoin.conf file. With this mechanism the configuration will persist and Xpedited service will be restarted when either your node or the other is restarted.
Two bitcoin.conf entries need to be made. One is the addnode connection which opens the connection to the remote peer and the
second is the expeditedblock entry which makes the request to begin the receipt of Xpedited blocks from this peer.
addnode=<ip:port>
expeditedblock=<ip:port>
You can have muliple addnode and expedited entries up to a maximum of 8 connections. See the following example:
addnode=10.233.34.33:8333
expeditedblock=10.233.34.33:8333
addnode=11.222.34.55:10500
expeditedblock=11.222.34.55:10500
addnode=45.33.223.34
expeditedblock=45.33.223.34
addnode=45.33.233.45:8333
expeditedblock=45.33.233.45:8333
addnode=42.33.233.45:8333
expeditedblock=42.33.233.45:8333
addnode=15.33.233.45:8333
expeditedblock=15.33.233.45:8333
addnode=45.33.22.45:8333
expeditedblock=45.33.22.45:8333
addnode=145.33.233.45:8333
expeditedblock=145.33.233.45:8333
You can also setup connections using the RPC interface, however once you restart your node the Xpedited forwarding will no longer be in effect and you will have to re-request forwarding unless you use a script of some kind to send the forwarding requests.
First, make sure the node you want expedited connections from is actually connected: getpeerinfo | grep "node IP addr"
If not: addnode "node IP addr" onetry
Using RPC is simple as follows:
expedited block|tx "node IP addr" on|off
For example, to turn on expedited forwarding of blocks from a remote peer to my peer you would enter the following:
bitcoin-cli expedited block "192.168.0.6:8333" on
and to do the same for transaction forwarding I would enter:
bitcoin-cli expedited tx "192.168.0.6:8333" on
To get more help on how to use the RPC commands you can type in "bitcoin-cli help expedited" from the command line, or if you ar using the debug console then simply type "help expedited".
- Putting limits on forwarding
By default the maximum number of recipients that can request forwarding from your node is set to 3. If you wish to limit that or reduce that you can use the following settings.
maxexpeditedblockrecipients=<n>
maxexpeditedtxrecipients=<n>