# Join Server

> The Join Server handles the LoRaWAN® join flow, including Network and Application Server authentication and session key generation.

Source: https://www.thethingsindustries.com/docs/concepts/architecture/components/join-server/


The Join Server handles the LoRaWAN® join flow, including Network and Application Server authentication and session key generation.

## Join procedure

Join Servers receive join-requests from [Network Servers](https://www.thethingsindustries.com/docs/concepts/architecture/components/network-server/) via gRPC and issue join-accepts for registered devices if join-request validation passes.

In case a join-request is accepted, the Join Server derives session security context, which contains the session keys and is identified by a session key ID. Join Servers encrypt derived network and application session keys using key encryption keys(KEKs) shared between [Network Servers](https://www.thethingsindustries.com/docs/concepts/architecture/components/network-server/) and [Application Servers](https://www.thethingsindustries.com/docs/concepts/architecture/components/application-server/) respectively and include the session keys in the join-accepts in encrypted form.

## Device Management

Join Servers expose [JsEndDeviceRegistry](https://www.thethingsindustries.com/docs/api/reference/grpc/end_device/#the-jsenddeviceregistry-service) service for end device management. Typical clients of this service are [Console](https://www.thethingsindustries.com/docs/concepts/architecture/components/console/) and [CLI](https://www.thethingsindustries.com/docs/concepts/features/cli/).

Join Servers store device root and session keys.

## Session Key Retrieval

Join Servers expose RPCs for retrieval of session keys given session key ID.

## Interoperability

Join Servers expose AS-JS, vNS-JS and hNS-JS services as defined by LoRaWAN Backend Interface 1.0 spec.