Designing a small network requires a thorough understanding of the network infrastructure and the essential components necessary for creating a reliable, scalable, and secure network. Below is an in-depth guide that outlines the essential components and considerations for designing a small network.


1. Network Infrastructure

The backbone of any network consists of critical equipment, services, and tools that ensure smooth and efficient operations. A well-designed network infrastructure must cater to current needs and be scalable for future growth. Here are the main components and considerations:


2. IP Addressing

         IP addressing is a fundamental aspect of network design. Choosing an appropriate IP address range is crucial for efficient network management and avoiding conflicts. For small networks, you typically choose from one of the following private IP address ranges:


  • Class A: 10.0.0.0/8 (10.0.0.0 – 10.255.255.255)
  • Class B: 172.16.0.0/12 (172.16.0.0 – 172.31.255.255)
  • Class C: 192.168.0.0/16 (192.168.0.0 – 192.168.255.255)

       Selecting the right class depends on the size and scale of the network. For instance, Class C is often sufficient for small networks, offering up to 65,536 addresses.

3. Layered Switching

        Effective switching is vital for managing data traffic efficiently across the network. The hierarchical network design model splits the network into three layers: Core, Distribution, and Access.


   Core Layer Switch

        The core layer is the backbone of the network, designed for high-speed data transfer and minimal latency. Core switches should have high bandwidth, CPU, and memory capacity to handle substantial traffic loads. It is recommended to have at least 5-10 times the capacity of the actual traffic. For example, if the total traffic is 1G, the switch uplink should be at least 5G. Port-channeling can provide additional redundancy and throughput.

Recommended Core Layer Switches:

    • Cisco Catalyst 9600
    • Cisco Catalyst 9500
    • Cisco 4500
    • Cisco 6500
    • Cisco Nexus 7000
    • Cisco Nexus 9000
    • Juniper EX3000
    • Juniper EX4000
    • Juniper EX9000

    Distribution Layer Switch

The distribution layer serves as an intermediary between the core and access layers, aggregating data from access switches and forwarding it to the core. This layer also handles routing between VLANs, policy-based security, and QoS (Quality of Service).
Recommended Distribution Layer Switches:

    • Cisco Catalyst 9300
    • Cisco Catalyst 9400
    • Cisco 4500
    • Cisco 3800
    • Cisco Nexus 5000
    • Cisco Nexus 2000 Extender (FEX)
    • Juniper EX2000

    Access Layer Switch

The access layer connects end devices like computers, printers, and IP phones to the network. It provides network access to users and enforces security policies.
Recommended Access Layer Switches:

    • Cisco 2960
    • Cisco 1000
    • Cisco 1200
    • Cisco 1300
    • Cisco 9200

4. Core Router

Core routers are critical for connecting different network segments and managing data traffic between them. They must be robust and capable of handling high traffic volumes.

Recommended Core Routers:

    • Cisco ISR 4300
    • Cisco ASR 1001/1002
    • Cisco ASR 1000 HX (for higher capacity)

5. Edge Router/Customer Edge (CE)

Edge routers manage external connectivity, such as MPLS and internet connections. They act as the network's gateway, ensuring seamless communication with external networks.
Recommended Edge Routers:
    • Cisco ASR 1001/1002

6. VPN Router

VPN routers provide secure connectivity for remote users and branch offices. When selecting a VPN router, ensure it supports ESP/IPSEC for secure communication.

Recommended VPN Routers:

    • Cisco ISR 4300
    • Cisco ASR 1001/1002

7. Firewall

Firewalls are essential for network security, protecting against unauthorized access and cyber threats. When choosing a firewall, consider your specific security needs and potential scalability. Some firewalls also offer additional functionalities like VPN and routing.
Recommended Firewalls:
    • Cisco ASA 5000
    • Cisco Firepower 2000
    • Fortinet 1000
    • Fortinet 1500D
    • Fortinet 601E
Note: While FortiGate firewalls are popular, they have been known to have reliability issues.

 

8. Routing Options

Routing protocols ensure efficient data transfer within the network and to external networks. The choice of routing protocol depends on network size and complexity.
    • OSPF (Open Shortest Path First): Suitable for larger, more complex networks as it quickly adapts to changes.
    • BGP (Border Gateway Protocol): Ideal for managing routing between different autonomous systems, often used in larger networks and ISPs.

9. Redundancy Protocol

Redundancy protocols are crucial for maintaining network availability and reliability. They provide failover mechanisms to ensure continuous operation in case of device or link failure.
    • HSRP (Hot Standby Router Protocol): Provides redundancy for IP networks, ensuring seamless traffic switching between multiple routers or upstream connections.

10. Additional Services

Running a small network efficiently requires various services and additional equipment. This includes servers for hosting applications, storage solutions, backup systems, and network management tools. Ensuring these services are well-integrated and maintained is key to a reliable network.

 


Designing a small network involves careful planning and selection of appropriate components. From IP addressing to choosing the right switches, routers, and firewalls, each element plays a vital role in creating a robust, scalable, and secure network. By considering the recommendations and guidelines provided, you can design a network that meets your current needs and accommodates future growth.