ISNs

iSNS stands for Internet Storage Name Service. It is an IETF standard and a centralized directory service designed to simplify the discovery and management of storage devices on IP networks. The primary purpose is to enable dynamic registration and lookup of iSCSI targets and initiators, as well as certain Fibre Channel over IP resources, within a scalable SAN environment.

iSNS uses a client/server model. Storage devices and initiators run iSNS clients that register with one or more iSNS servers, providing identifying attributes such as device name, IP address, type, and capabilities. The server maintains a registry and responds to discovery queries, allowing initiators to locate available targets without manual configuration.

Key capabilities of iSNS include dynamic registration, management of device addresses and service attributes, grouping or scoping to organize resources, and access-control policies that govern which devices can discover or access particular targets. The service supports updates and removals of registrations as devices change, enabling more flexible SAN management.

In deployment, iSNS is typically used in larger enterprise SANs to facilitate scalable iSCSI and Fibre Channel deployments across networks. It complements other storage management mechanisms, such as LUN mapping and zoning, by providing a searchable directory of devices and the relationships between initiators and targets.

Security considerations for iSNS include authentication and access controls to protect the directory, as well as measures to prevent unauthorized updates or queries. While not universally adopted by all vendors, iSNS remains a viable option for centralized discovery and management in suitable environments.