SCHC Adaptation Layer
🔤 Acronyms? See the Glossary
SCHC adaptation layer enables the use of the IP stack on very constrained networks for end-to-end IP communication from the object to the application. It dynamically adapts compression and fragmentation to the underlying network conditions and capabilities, overcoming the variability of LoRaWAN parameters between regions, operators, and radio conditions.
About Stacks​
In a stack, each protocol layer relies on those below in order to provide additional functionality.
There are two major models:
- The OSI (Open Systems Interconnection) reference model with 7 layers stacked on top of each other.
- The TCP/IP model, based on OSI, where layers 5 and 6 are merged into layer 7 to form a single "Application" layer.
SCHC model activates the IP stack on constrained IoT networks by bringing an adaptation layer between levels 2 and 3. Like a bridge over LPWAN and IP, it ensures technology adaptation from level 1 through level 2, and application adapation from level 2 up to level 5.
Media Layers​
In the OSI and TCP/IP models, levels 1 to 3 are "media" layers and level 4 to 7 are "host" layers. SCHC adapatation process occurs at the level of the media layers dealing with frames and packets.
LoRaWAN is a media access control (MAC) protocol for wide area networks. LoRaWAN can be mapped to the second and third layer of the OSI model (Credit @The Things Network). SCHC goes further by mapping the IP upper layer to them, resulting in a continuous IP stack activation from bottom to top.
Use Case Smart Electricity Meters​
Applied to the use case of Smart Electricity Meters, the role of SCHC Adaptation Layer is obvious.
Deployed on both the connected object and the core of the network, it ensures the interoperability along the whole uplink to the head-end system.
