Locking is the means to avoid concurrent modifications to a TopologyElement or Network and their components. Clients shall use the locking services if they need to make a set of changes (for example, several Write operations and Method invocations) and where a consistent state is available only after all of these changes have been performed. The main purpose of locking a TopologyElement is avoiding concurrent modifications. The main purpose of locking a Network is avoiding concurrent topology changes.
A lock from one Client usually allows other Clients to view (navigate/read) the locked element. Servers may choose to implement an exclusive locking where other Clients have no access at all (e.g. in cases where even read operations require certain settings in a TopologyElement).
If the Online/Offline model is supported (see 7.3), the lock always applies to both the online and the offline version.
When locking a Network, the lock applies to the Network and all connected TopologyElements. If any of the connected TopologyElements provides access to a sub-ordinate Network (like a gateway), the sub-ordinate Network and its connected TopologyElements are locked as well.