Abstract: I welcome you to the fourth issue of the IEEE Communications Surveys and Tutorials in 2021. This issue includes 23 papers covering different aspects of communication networks. In particular, ...

Ensure atomicity by using the SETNX operation. Implements a Pub/Sub messaging system between the client attempting to acquire the lock and the one currently holding it. Includes a forced timeout ...

Persistent structures implemented on top of Hashes. Supports secondary indexes to allow filtering on equality, inequality, ranges, less/greater-than, and a basic full-text search index. The full-text ...