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CH10: minor edits

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David A. Harding 2023-05-18 15:48:15 -10:00
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@ -5,7 +5,7 @@
(P2P)")))Bitcoin is structured as a peer-to-peer network architecture on (P2P)")))Bitcoin is structured as a peer-to-peer network architecture on
top of the internet. The term peer-to-peer, or P2P, means that the top of the internet. The term peer-to-peer, or P2P, means that the
full nodes which participate in the network are peers to each other, that full nodes which participate in the network are peers to each other, that
they can all equal, and that there are no "special" nodes. they can all perform the same functions, and that there are no "special" nodes.
The network nodes The network nodes
interconnect in a mesh network with a "flat" topology. There is no interconnect in a mesh network with a "flat" topology. There is no
server, no centralized service, and no hierarchy within the network. server, no centralized service, and no hierarchy within the network.
@ -44,20 +44,17 @@ protocols in this chapter in addition to the base Bitcoin P2P protocol.
id="BNnode08")))((("Bitcoin nodes", "types and roles", id="BNnode08")))((("Bitcoin nodes", "types and roles",
id="BNtype08")))Although full nodes (peers) in the Bitcoin P2P network are equal to each other, id="BNtype08")))Although full nodes (peers) in the Bitcoin P2P network are equal to each other,
they may take on different roles depending on the functionality they are they may take on different roles depending on the functionality they are
supporting. A Bitcoin node is a collection of several functions: validation, supporting. A Bitcoin full node validates blocks and may contain other
routing, mining, and wallet services. functions, such as routing, mining, and wallet services.
All full nodes include the validation function and
might include other functionality.
Some nodes, called _archival full nodes_, also maintain a Some nodes, called _archival full nodes_, also maintain a
complete and up-to-date copy of the blockchain. Full nodes can complete and up-to-date copy of the blockchain. Full nodes can
autonomously and authoritatively verify any transaction without external autonomously and authoritatively verify any transaction without external
reference. ((("simple-payment-verification (SPV)"))) Those nodes can reference. ((("simple-payment-verification (SPV)"))) Those nodes can
serve data to clients that stor serve data to clients that store
only a subset of the blockchain and verify transactions using a method only a subset of the blockchain and verify transactions using a method
called _simplified payment verification_, or SPV. ((("lightweight called _simplified payment verification_, or SPV. ((("lightweight
clients")))These nodes are known as lightweight clients. clients")))These clients are known as lightweight clients or SPV clients.
((("Bitcoin nodes", "mining nodes")))((("mining and consensus", "mining ((("Bitcoin nodes", "mining nodes")))((("mining and consensus", "mining
nodes")))((("Proof-of-Work algorithm")))((("mining and consensus", nodes")))((("Proof-of-Work algorithm")))((("mining and consensus",
@ -100,7 +97,6 @@ protocols. These other protocol nodes are mostly pool mining nodes (see
<<mining>>) and lightweight wallet clients, which do not carry a full <<mining>>) and lightweight wallet clients, which do not carry a full
copy of the blockchain. copy of the blockchain.
=== Compact Block Relay === Compact Block Relay
When a miner finds a new block, they announce it to the Bitcoin network When a miner finds a new block, they announce it to the Bitcoin network
@ -302,7 +298,7 @@ acknowledge the +version+ message and establish a connection by sending
a +verack+. a +verack+.
How does a new node find peers? The first method is to query DNS using a How does a new node find peers? The first method is to query DNS using a
number of "DNS seeds," which are DNS servers that provide a list of IP number of _DNS seeds_, which are DNS servers that provide a list of IP
addresses of Bitcoin nodes. Some of those DNS seeds provide a static addresses of Bitcoin nodes. Some of those DNS seeds provide a static
list of IP addresses of stable Bitcoin listening nodes. Some of the DNS list of IP addresses of stable Bitcoin listening nodes. Some of the DNS
seeds are custom implementations of BIND (Berkeley Internet Name Daemon) seeds are custom implementations of BIND (Berkeley Internet Name Daemon)
@ -434,7 +430,7 @@ startref="BNextend08")))((("", startref="BNodiscover08")))
=== Full Nodes === Full Nodes
Full nodes are nodes that verify every transaction in every block on the Full nodes are nodes that verify every transaction in every block on the
valid block chain with the most proof of work. valid blockchain with the most proof of work.
((("blocks", "genesis block")))((("genesis block")))((("blockchain ((("blocks", "genesis block")))((("genesis block")))((("blockchain
(the)", "genesis block")))Full nodes (the)", "genesis block")))Full nodes
@ -445,7 +441,7 @@ verify any transaction without recourse or reliance on any other node or
source of information. The full node relies on the network to source of information. The full node relies on the network to
receive updates about new blocks of transactions, which it then verifies receive updates about new blocks of transactions, which it then verifies
and incorporates into its local view of which scripts control which and incorporates into its local view of which scripts control which
Bitcoins, called the set of _unspent transaction outputs_ (UTXOs). bitcoins, called the set of _unspent transaction outputs_ (UTXOs).
((("Bitcoin nodes", "full nodes")))Running a full node gives ((("Bitcoin nodes", "full nodes")))Running a full node gives
you the pure Bitcoin experience: independent verification of all you the pure Bitcoin experience: independent verification of all
@ -516,12 +512,6 @@ This process of comparing the local blockchain with the peers and
retrieving any missing blocks happens any time a node goes offline for retrieving any missing blocks happens any time a node goes offline for
an extended period of time. an extended period of time.
//FIXME?
//[[inventory_synchronization]]
//[role="smallerfifty"]
//.Node synchronizing the blockchain by retrieving blocks from a peer
//image::images/mbc2_0806.png["InventorySynchronization"]
[[spv_nodes]] [[spv_nodes]]
=== Simplified Payment Verification (SPV) Nodes === Simplified Payment Verification (SPV) Nodes
@ -623,7 +613,7 @@ developers added a feature called _bloom filters_ in an attempt to
reduce the bandwdith that SPV clients needed to use to learn about their reduce the bandwdith that SPV clients needed to use to learn about their
incoming and outgoing transactions. incoming and outgoing transactions.
Bloom filters allow SPV clients to receive a subset of Bloom filters allow SPV clients to receive a subset of
the transactions without directloy revealing precisely which addresses they are the transactions without directly revealing precisely which addresses they are
interested in, through a filtering mechanism that uses probabilities interested in, through a filtering mechanism that uses probabilities
rather than fixed patterns.((("", startref="BNspvnodes08")))((("", rather than fixed patterns.((("", startref="BNspvnodes08")))((("",
startref="simple08"))) startref="simple08")))
@ -821,7 +811,7 @@ then look for patterns and relationships between the transactions.
Randomly-selected false positive transactions would be unlikely to have Randomly-selected false positive transactions would be unlikely to have
a parent-child relationship from output to input, but transactions from a parent-child relationship from output to input, but transactions from
the user's wallet would be very likely to have that relationship. If the user's wallet would be very likely to have that relationship. If
all of the related tranactions have certain characteristics, such as all of the related transactions have certain characteristics, such as
at least one P2PKH output, then transactions without that characteristic at least one P2PKH output, then transactions without that characteristic
can be assumed not to belong to the wallet. can be assumed not to belong to the wallet.
@ -832,7 +822,7 @@ which could lead to denial-of-service attacks.
For both of those reasons, Bitcoin Core eventually limited support for For both of those reasons, Bitcoin Core eventually limited support for
bloom filters to only clients on IP addresses that were explicitly bloom filters to only clients on IP addresses that were explicitly
allowed by the node operator. This meant that an alternative method for allowed by the node operator. This meant that an alternative method for
helping SPV cients find their transactions was needed. helping SPV clients find their transactions was needed.
=== Compact Block Filters === Compact Block Filters