Block Node Types and Tiers
Overview
Block Nodes can offer many services and features. The core system encompasses a wide array of flexible options made possible by composing relatively small and focused "plug-ins" within a framework designed to support very low latency processing of high volume block stream data. There are many "types" of block nodes discussed in various places, each of which is actually the same core block node, with different combinations of "plug-ins" deployed. This demonstrates the flexibility of the block node system to meet a specific set of needs, but the many names and terms also leads to much confusion. This document seeks to better define the various terms and names, as well as provide a visual representation of where different block node instances might fit into an example network.
This document is intended for a general audience, and does not describe the technical details of operation, access, internal "plug-ins" deployed, facilities or any other internal detail. This document, instead, focuses on services offered and operating intent.
Block Node Types and Tiers Visualized
Definitions
Block Node ServicesFull HistoryA service provided by some block nodes that choose to make available the entire history of the associated Hiero network, from genesis (or general availability in the case of the Hedera network).Partial HistoryA service provided by some block nodes that choose to make available a subset of the history of the associated Hiero network, starting from a particular block, or for a particular duration, or based on other criteria.Private ArchiveA service provided by some block nodes that receive the block stream and store the data in an archive for the benefit of a particular entity, rather than the network as a whole. Examples include cloud buckets, long-term tape, or replicated local disks. Private archives are often intended for disaster recovery or offline analysis.Future extensions (planned)The plugin system is designed to support additional services in future releases, such as custom analytics, interledger bridges, dApp-specific stream processing, and filtered block streams. None of these are provided by a standard Block Node deployment today.Block Node TypesRolling-HistoryA type of node that chooses to manage only "recent" history. May offer other services that do not require more than a day (or other limited duration) of locally stored history. Most Tier 2 nodes are expected to be this type of node. A "Private Archive" service could be provided by this type of node. Rolling-History provides a particular type of "Partial History" service.Full NodeA type of node that retains the complete block history of the network on local storage, from genesis. State management and state proof services are planned for a future release and are not yet available.Light NodeAnother type of "Rolling-History" or other "Partial History" node. A Light Node is a good option for developing and testing new block stream based services, or providing services that do not require the full history of the network.Private-CloudAnother name for a block node that serves a Private Sphere. This type of node could provide almost any service, or only very few.Archive ServerA theoretical type of node that provides a client-only service. Reads blocks from an archival source and delivers them on demand. This type of Node does not stream data or provide state management.Community NodeA Block Node operated by any entity other than a network council member or an entity contracted by the network council to operate block nodes.Block Node TiersTier 1A Block Node that receives its Block Stream data directly from Consensus Nodes. Tier 1 Block Nodes are critical to the operation of the Consensus Network, and it is expected that, eventually, each Consensus Node operator will need to run their own Tier 1 Block Node in a "Full Node" configuration.Tier 2A Block Node that receives its Block Stream data from another Block Node (typically a Tier 1 Block Node) via the block stream subscribe API. Tier 2 Block Nodes are still required to verify the Block Stream received, but are not required to store the full history of the network or provide a Full Node configuration. Some Tier 2 nodes may, nonetheless, _choose_ to operate a Full Node configuration and offer Full History services.
Last updated