IEEE 802.21 refers to a standard developed by the IEEE for Media Independent Handover (MIH). The primary goal of this standard is to facilitate handovers between heterogeneous networks, ensuring seamless connectivity for users.
Here’s a concise overview of IEEE 802.21:
Purpose: The main objective of IEEE 802.21 is to provide mechanisms that assist in handovers between different types of networks, such as Wi-Fi (IEEE 802.11) and cellular networks (like 3G, 4G, or 5G).
Media Independence: The “media independent” aspect means that the handover is not tied to any specific type of network. It provides a generic framework that can support handovers between various network types.
Components:
- MIH Function (MIHF): This is a key component of 802.21. It provides the necessary functionalities to achieve the objectives of the standard.
- MIH Users (MIHUs): Entities, like applications or upper-layer protocols, that use MIHF services.
Services: There are three main services defined:
- Event Service: Notifies the MIH User about events in the network, such as a change in link quality.
- Command Service: Allows the MIH User to instruct the MIHF to perform certain actions, like starting a handover.
- Information Service: Provides information about neighboring networks that can be used for handover decisions.
Applications: Apart from the traditional handover scenarios, 802.21 can also be used in scenarios like mobile VPNs, multi-networking, bandwidth aggregation, and more.
Interactions: IEEE 802.21 doesn’t dictate the actual handover process but rather provides tools to make better handover decisions. The actual process of switching between networks is left to the respective technologies.
In summary, IEEE 802.21 provides a framework to enhance the handover experience for users moving between different types of networks, promoting a more seamless and continuous connectivity experience.