> For the complete documentation index, see [llms.txt](https://isdn.learn-telecom.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://isdn.learn-telecom.com/layers/network-layer.md).

# Network Layer

#### ISDN Network Layer

The ISDN (Integrated Services Digital Network) Network Layer is responsible for the transmission of data across the ISDN network. 

It primarily follows the specifications of the ITU-T Q.931 protocol for signaling, which manages call setup, control, and termination. 

It operates at the third layer of the OSI model, handling logical and physical addressing, ensuring data integrity, and facilitating error handling and correction mechanisms. 

By leveraging both B-channels for data transfer and D-channel for signaling, the ISDN Network Layer ensures efficient and reliable communication between devices.