Anatomy of a Design: Determine the right network requirements

infrastructure designThis is the second post in a series about IT infrastructure design.

In our last post on IT infrastructure, we examined the general requirements of a hypothetical law firm in need of a new infrastructure. Now, we’ll research network requirements, because without the network, business as usual grinds to a halt.

In this example you can see how an organization’s employees, business, and other requirements influence the best solution for its needs. Think about the factors that go into determining this solution and how they might apply to your own organization.

What IT needs does a law firm have?

Our hypothetical law firm has 10 lawyers, four paralegals, and four administrative assistants — 18 employees who all need network access. The firm will need secured wireless network access throughout the office for the lawyers’ laptops and tablets (WPA2-AES being the most secure wireless encryption); paralegals and administrative staff will be using desktops computers, also with a wireless connection.

The firm needs Internet access to conduct its business, and at times, VPN access to its clients’ networks. At a minimum, the firm’s network must be equipped with security against intrusion, which means firewalls, intrusion prevention, secure VPN, and external routing.

The network isn’t very large, nor does it consist of many devices. Let’s assume every employee requires a wireless connection (to make the overall solution simpler). To support the wireless connectivity needs, at least one high-quality switch is required. The switch is capable of supporting at least a dozen connections for the wireless access points with gigabit ports, and another half dozen ports for the Internet router/firewall and primary server.

The ideal infrastructure should have two switches with overlapping access points, but this would be cost prohibitive. Instead, we’ll opt for dual power supplies, and forgo excessive network component redundancy. This means the infrastructure will have only one switch and one set of access points all connected to the switch with as much internal redundancy as the firm can reasonably afford.

The number of access points can be estimated based on the physical office space and how many possible connections need to be supported. Since access points aren’t expensive (this is relative, of course), we’ll use a total of six scattered around the office in strategic locations to support the staff and any visitors to the conference room. We’ll require the latest wireless standard, which is 802.11ac and supports a 1 Ghz connection, for the overall design.

Generally, a wireless site survey would be completed, but it may actually be cheaper to over-specify the number of access points for this small office. Instead of calculating the optimal number of access points through a survey, more access points can be purchased to eliminate the problem entirely.

Our checklist of requirements

Our hypothetical small law firm has yielded five specific needs for an IT infrastructure.

  1. A high-quality switch with redundant power supplies (this may seem a bit vague, but it will help narrow the field of possible vendors). Also required are gigabit speed (1 GbE) ports and low latency and high throughput, if affordable.
  2. At least 24 switch ports on a single primary switch for connecting to all the various network devices (access points, server(s), and firewall/router).
  3. Six wireless access points to support all users running wireless security protocol WPA2-AES, and adhering to the 802.11ac gigabit wireless standard.
  4. A firewall/router capable of supporting encrypted VPN to a client’s network.
  5. Wireless management for the six access points.

This solution would require, at most, less than 10 physical devices from perhaps two different vendors. A slightly larger firm or one with a larger office space might need a few more wireless access points, which may imply a larger primary switch with more ports, but overall this IT infrastructure is a fairly clear and easily purchased solution.

Implementing the solution will require some professional services, since lawyers are good at providing legal services, not technical services. But, given the size of the network, it shouldn’t break the budget.

Every organization is different of course, and the solution that makes the most sense for this law firm might not make sense for you. But determining your employees’ requirements and your organization’s goals will often reveal the best equipment, installation, and overall solution for your needs.

Designing the right infrastructure can pose complex problems for your organization. In the next post, we’ll examine the server and desktop requirements — what is generally referred to as compute.

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