diff --git a/protocol/forks/bip-0159.md b/protocol/forks/bip-0159.md new file mode 100644 index 0000000..29eaa3a --- /dev/null +++ b/protocol/forks/bip-0159.md @@ -0,0 +1,64 @@ +
+ BIP: 159 + Layer: Peer Services + Title: NODE_NETWORK_LIMITED service bit + Author: Jonas Schnelli+ +== Abstract == + +Define a service bit that allow pruned peers to signal their limited services + +==Motivation== + +Pruned peers can offer the same services as traditional peer except of serving all historical blocks. +Bitcoin right now only offers the NODE_NETWORK service bit which indicates that a peer can serve +all historical blocks. +# Pruned peers can relay blocks, headers, transactions, addresses and can serve a limited number of historical blocks, thus they should have a way how to announce their service(s) +# Peers no longer in initial block download should consider connecting some of its outbound connections to pruned peers to allow other peers to bootstrap from non-pruned peers + +== Specification == + +=== New service bit === + +This BIP proposes a new service bit + +{|class="wikitable" +|- +| NODE_NETWORK_LIMITED || bit 10 (0x400) || If signaled, the peer MUST be capable of serving at least the last 288 blocks (~2 days). +|} + +A safety buffer of 144 blocks to handle chain reorganizations SHOULD be taken into account when connecting to a peer signaling the+ Comments-Summary: No comments yet. + Comments-URI: https://github.com/bitcoin/bips/wiki/Comments:BIP-0159 + Status: Draft + Type: Standards Track + Created: 2017-05-11 + License: BSD-2-Clause +
NODE_NETWORK_LIMITED service bit.
+
+=== Address relay ===
+
+Full nodes following this BIP SHOULD relay address/services (addr message) from peers they would connect to (including peers signaling NODE_NETWORK_LIMITED).
+
+=== Counter-measures for peer fingerprinting ===
+
+Peers may have different prune depths (depending on the peers configuration, disk space, etc.) which can result in a fingerprinting weakness (finding the prune depth through getdata requests). NODE_NETWORK_LIMITED supporting peers SHOULD avoid leaking the prune depth and therefore not serve blocks deeper than the signaled NODE_NETWORK_LIMITED threshold (288 blocks).
+
+=== Risks ===
+
+Pruned peers following this BIP may consume more outbound bandwidth.
+
+Light clients (and such) who are not checking the nServiceFlags (service bits) from a relayed addr-message may unwillingly connect to a pruned peer and ask for (filtered) blocks at a depth below their pruned depth. Light clients should therefore check the service bits (and eventually connect to peers signaling NODE_NETWORK_LIMITED if they require [filtered] blocks around the tip). Light clients obtaining peer IPs though DNS seed should use the DNS filtering option.
+
+== Compatibility ==
+
+This proposal is backward compatible.
+
+== Reference implementation ==
+
+* https://github.com/bitcoin/bitcoin/pull/11740 (signaling)
+* https://github.com/bitcoin/bitcoin/pull/10387 (connection and relay)
+
+== Copyright ==
+
+This BIP is licensed under the 2-clause BSD license.
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