Question E8C15:
What technique do individual nodes use to form a mesh network?  

Choices:  
A: Forward error correction and Viterbi codes  
B: Acting as store-and-forward digipeaters  
C: Discovery and link establishment protocols  
D: Custom code plugs for the local trunking systems    

Correct Answer is  C: Discovery and link establishment protocols  

Correct answer: C — Discovery and link establishment protocols

Why C is correct:
- Mesh networks are self-forming and self-healing. Each node periodically discovers neighbors (e.g., via beacon/HELLO messages) and establishes links, then runs a routing protocol to choose paths.
- Common examples include OLSR, BATMAN, and AODV, which handle neighbor discovery, link-quality assessment, and route computation.

Why the others are incorrect:
- A: Forward error correction and Viterbi codes improve bit error performance, but they do not discover neighbors or build network topology.
- B: Acting as store-and-forward digipeaters is a static, simple relaying method (typical of APRS), not dynamic, multi-path routing. Mesh uses dynamic routing, not basic digipeating.
- D: Custom code plugs are programming files for trunked LMR systems (channels, talkgroups). They are unrelated to ad hoc mesh formation.

Rules of thumb:
- Mesh = dynamic neighbor discovery + link establishment + routing.
- Digipeater ≈ simple, predefined store-and-forward; Mesh ≈ adaptive multi-hop routing with automatic path selection.