  An outstanding problem in the design of distributed ledgers concerns policies
that govern the manner in which users interact with the network. Network
usability is crucial to the mainstream adoption of distributed ledgers,
particularly for enterprise applications in which most users do not wish to
operate full node. For DAG-based ledgers such as IOTA, we propose a user-node
interaction mechanism that is designed to ensure the risk of a user
experiencing a poor quality of service is low. Our mechanism involves users
selecting nodes to issue their transactions to the ledger based on quality of
service indicators advertised by the nodes. Simulation results are presented to
illustrate the efficacy of the proposed policies.
