Comprehensive Network Design & Implementation

I'm seeking an experienced network engineer to design and implement a comprehensive network. This project aims to test your knowledge of the OSI layers of networking, particularly the network, transport, and application layers.

Key Objectives:
1. Facilitate email exchange through an email server.
2. Utilize DHCP server pools across different subnets.
3. Design and control a 'Smart Home' via an IoT Gateway.
4. Implement fundamental cybersecurity measures to protect the network from malicious use.
5. Establish basic Quality of Service (QoS) for online game servers, considering bandwidth and latency.

Skills and Experience Required:
- Extensive understanding of OSI networking layers.
- Proficiency in network design and implementation.
- Experience with email servers and protocols (not specific to any).
- Familiarity with DHCP server pools and IoT Gateways.
- Knowledge of basic cybersecurity measures.
- Expertise in establishing Quality of Service (QoS).

Please note that there's no specific preference for the email exchange protocols or technologies, nor for the email server. The cybersecurity aspects are also not specific; a comprehensive protective strategy would be appreciated.

The network deployment will be for a small-scale network.