PrevRoleRestorer to manage role restoration (#11731)
This commit introduces `Mle::PrevRoleRestorer` to consolidate the logic for restoring a device's previous role (child or router/leader) after an MLE restart. This new class replaces and encapsulates the functionality from the now-removed `RouterRoleRestorer` class and `RestorePrevRole()` method. `PrevRoleRestorer` manages its own timer and retransmission logic. It handles sending Child Update Requests to restore a child role, or multicast Link Requests to restore a router/leader role. It also adds a small random delay before the first transmission attempt to avoid synchronized transmissions when multiple devices restart at once. This change simplifies the `Mle` class by centralizing all role restoration logic into a single component, making future enhancements to this process easier.
What is OpenThread?
OpenThread released by Google is...
...an open-source implementation of the Thread networking protocol. Google Nest has released OpenThread to make the technology used in Nest products more broadly available to developers to accelerate the development of products for the connected home.
...OS and platform agnostic, with a narrow platform abstraction layer and a small memory footprint, making it highly portable. It supports both system-on-chip (SoC) and network co-processor (NCP) designs.
...a Thread Certified Component, implementing all features defined in the Thread 1.4.0 specification, including all Thread networking layers (IPv6, 6LoWPAN, IEEE 802.15.4 with MAC security, Mesh Link Establishment, Mesh Routing) and device roles, as well as Border Router support.
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...then openthread.io is the place for you.
Note: For users in China, end-user documentation is available at openthread.google.cn.
If you're interested in contributing to OpenThread, read on.
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