If you’re looking for a network design focused on network infrastructure, firewalls, routing protocols (BGP, OSPF), and security, here is a detailed approach that would support a business with over 10 years of experience.

1. Network Architecture Design

The overall network design should be scalable, secure, and resilient. The structure would typically include:

• Core Network: A backbone of high-capacity switches and routers to connect different segments of the network.
• Edge Network: Connecting to external ISPs or cloud services. This includes firewalls, routers, and load balancers to ensure proper segmentation and security.
• Access Network: The segment where end-user devices and servers connect, typically using access switches that segment traffic within the company.

2. Routing Protocols

The correct use of routing protocols will ensure that your network is reliable and scalable.

• BGP (Border Gateway Protocol): BGP is used to manage how data is routed between different autonomous systems (ASes) on the internet. If your business has multiple ISPs or requires failover for high availability, BGP is crucial.

  • IBGP (Internal BGP): IBGP is used within a single AS to ensure all routers within that AS have the same routing table. It’s essential for large enterprises with multiple locations.
  • EBGP (External BGP): EBGP is used to connect your network to external networks, such as ISPs or cloud providers.
  • BGP Attributes: Set up proper BGP attributes like AS path, Local Preference, and MED (Multi-Exit Discriminator) to control routing decisions.

• OSPF (Open Shortest Path First): OSPF is a link-state routing protocol used within an enterprise. It works well in environments where you need faster convergence and efficient use of network resources.

  • OSPF Areas: Divide the network into areas (backbone area, regular areas) for efficient routing. Each area will have its own topology, and the backbone area will act as the central hub.
  • LSA (Link-State Advertisement): OSPF uses LSAs to share routing information, which reduces the need for unnecessary updates and enhances scalability.

• Integration of BGP and OSPF: In large networks, both BGP and OSPF might need to be used in conjunction. For example, BGP can be used for external routing, while OSPF is used for internal routing.

3. Firewall Design and Security

Network security must be a core focus, especially for a business with long experience and a potential large number of users or sensitive data.

• Next-Generation Firewalls (NGFW): These firewalls (e.g., Palo Alto Networks, Cisco Firepower) provide more advanced security features than traditional firewalls, including:

  • Application Layer Filtering: Block or allow traffic based on application behavior.
  • Intrusion Detection/Prevention Systems (IDS/IPS): Detect and prevent threats such as malware, SQL injections, and DDoS attacks.
  • Deep Packet Inspection (DPI): Analyze packets for malicious content and enforce network security policies.

• Segmentation & DMZ (Demilitarized Zone): Design your network with security zones to isolate different services:

  • DMZ: A segment between internal and external networks, hosting public-facing services like websites, mail servers, etc.
  • Internal Segmentation: Use VLANs or subnets to separate sensitive internal networks (HR, finance, etc.) from general user traffic.
  • Firewall Rules: Apply strict firewall rules to control access between segments and block unauthorized communication.

• VPN (Virtual Private Network): Set up VPNs for secure remote access. You can use technologies like IPsec or SSL-based VPNs to ensure that employees can access the internal network securely when working remotely.

• Zero Trust Architecture: Implement a Zero Trust approach, meaning every device, user, and application is treated as untrusted until proven otherwise. This can be supported through features like multi-factor authentication (MFA), identity and access management (IAM), and continuous monitoring.

4. Network Redundancy & High Availability

• Redundant Internet Connections: Use multiple ISPs to ensure availability even if one connection goes down. BGP will allow automatic rerouting if one of the links fails.
• Hot/Cold Standby Routers: Use a high-availability setup (e.g., HSRP, VRRP, or GLBP) for routers and switches to ensure that if one router goes down, another automatically takes over.
• Load Balancers: Implement load balancing for internal applications and external traffic, ensuring that the system can handle spikes in traffic without performance degradation.

5. Routing and Access Control

• Access Control Lists (ACLs): Implement ACLs on routers and firewalls to control which devices can access the network and its resources. Use ACLs to filter traffic based on IP addresses, ports, and protocols.
• Routing Policy Control: Use routing policies to control the path that data takes across your network. This can be done using BGP attributes such as AS path, Local Preference, and MED, or by using policy-based routing to direct traffic based on application requirements or performance needs.

6. Network Monitoring & Intrusion Detection

• SNMP (Simple Network Management Protocol): Use SNMP for monitoring network devices (routers, switches, firewalls) and getting real-time status updates.
• SIEM (Security Information and Event Management): Implement a SIEM system (e.g., Splunk, SolarWinds) to collect logs from firewalls, routers, and switches to analyze and detect potential security threats.
• IDS/IPS: Deploy Intrusion Detection Systems (IDS) or Intrusion Prevention Systems (IPS) for detecting suspicious activity and attacks in real-time.

7. VLANs & Subnetting

• VLAN Design: Create VLANs for segmenting traffic based on function (e.g., HR, Finance, IT, Users) to improve network performance and security. This also helps in applying specific firewall rules for different types of traffic.
• Subnetting: Design a subnet plan for efficient IP address management and minimal broadcast traffic. For example, use private IP ranges (e.g., 10.x.x.x, 192.168.x.x) and assign subnets based on departments or functions.

8. Security Protocols and Encryption

• IPSec & SSL/TLS: Use IPSec for site-to-site VPNs to encrypt traffic between locations. For web applications, ensure SSL/TLS encryption is implemented for all data in transit.
• Secure Routing Protocols: For routing security, enable BGP MD5 authentication and OSPF authentication to protect against route hijacking or spoofing.

9. Cloud Integration & Hybrid Networks

• Hybrid Cloud Design: If your business uses or plans to use cloud services (e.g., AWS, Azure), ensure your network is designed to securely connect on-premises infrastructure with the cloud. Use VPNs or dedicated direct connections for secure communication.
• Cloud Firewalls: For cloud-hosted resources, use cloud-native firewalls like AWS Security Groups, Azure Network Security Groups, or Google Cloud Firewalls for granular control.

By designing a network with proper routing, security, and high-availability measures, you ensure a robust, scalable, and secure infrastructure that meets the needs of a business with over 10 years of experience. Proper integration of BGP, OSPF, and firewall rules will ensure the network is resilient, performs optimally, and is secure from internal and external threats.