Summary

HELD provides a query protocol interface for IP devices, invited applications, and authorized third parties making unsolicited requests for target device location. Requests include

• Location request by type

• Create, update, and delete contexts

• Location assertion and location signing

The LIS implements the HELD protocol. It combines context data with ALE measurement information to determine location and responds to HELD requests. Several types of LIS variants are possible depending on deployment scenarios. Examples of deployment scenarios are provided in the following chapters.