Final answer:
A layered network model benefits protocol design by breaking down communication tasks into smaller, manageable components and ensures isolation between layers so that changes in one do not affect the others.
Step-by-step explanation:
Two benefits of using a layered network model are that it assists in protocol design and it prevents technology in one layer from affecting other layers. The layered model divides the network communication process into smaller and simpler components, allowing protocol design to be more manageable because each layer can be developed independently. Furthermore, isolation between layers ensures that changes or problems in one layer do not adversely impact other layers, which contributes to the overall robustness and flexibility of network architecture.