7.2 End-to-End Establishment of Application Link Key

In a secure network, when two devices need to communicate on a secure link with each other, the devices must request a link key from the trust center.

The following figure illustrates link key establishment between two routers. The router 0x0b6f requests a link key from the trust center (see packet #24) to communicate with the router 0x3779.

Figure 7-2. Link Key Establishment Between Two Routers
The trust center uses the Transport Key command to send the link key to both the routers. The link key is applied in further data exchange between the routers. Packet #47 uses this link key. The following figure illustrates the link key.
Figure 7-3. Link Key Establishment between Two Routers