---
title: Node strategy when depth changes
---
## Node strategy

- ultimately: maximise profit
- indirectly: comply with the rules of the reserve

### Network growth

- Increase of demand lead to depth change: `d -> d' (d'=d+1)`
- When by following the rules of the reserve, all chunks of a PO is evicted (moved to cache) and a chunk of a higher PO is deleted first
- Pull syncing as a neighbour now only with peers within node's storage depth
- Peers in PO `d`of old depth switch live pull syncing only their PO `d`
- Some peers in PO `d` can now be disconnected as Kademlia topology dictates

### Network contraction

- Decrease of demand lead to depth change: `d -> d' (d'=d-1)`
- When following the rules of the reserve, keep making sure there is consensus on the reserve
- Triggered
- When there is a chance that PO `d'` can be syncronised
- by too low utilisation (<50%) of node reserve of chunks in `PO >= d`
- Pretend storage is already `d-1`:
- Repopulate from cache all chunks of PO `d'`
- Connect to peers in PO bin `d'` to achieve full connectivity
- Pull sync peers of PO `d'` their PO bin-s PO-s`>= d` historically
- if all 3 successful then we reset `d` to `d'`

## Rules of the reserve