What is SD-Access?

Cisco SD-Access (Software-Defined Access) in Cisco's official term is this is an "intent-based networking architecture approach that delivers automated, secure, and scalable wired and wireless campus networks." What does this actually mean? To understand its actual use cases and benefits of SD-Access, you must first understand what the components of a Traditional Campus LAN are, what issues we have with Traditional Campus LANs and what problems SD-Access attempts to solve.

Common Campus LAN Requirements

Regardless of whether we are using a traditional LAN approach or an SDA approach to building the campus LAN there are some common requirements that apply to almost all properly scoped LAN designs. However this can vary depending on scope. The main areas of consideration are the following:

1. Figuring out the scope - A network can be just a switch, AP and router at a small remote site, or a complex network for a business that has complex security, speed, scalability and other requirements. The primary design options are grouped by scale and then selectively make adjustments based on the requirements, capabilities and needs of the organisation.
2. Redundant, Resilient and Always On - Network are usually very critical infrastructure, once again depends on the scope. Big organisations such as Hospitals, Banks, Airports etc all require almost 99% uptime to ensure the business keeps running. They absolutely cannot afford a network outage or a critical server being inaccessible. There can be considerable harm to an organisation if they face such a situation, from reputational damage to financial Loss, the impact can be severe. The scale of how tolerant a business will be to a network failure depends on the organisation and its operations.
3. Security - An organisation needs to always be protected. In network terms we need to address both physical security to our network devices, as well as logical security on the actual network devices themselves.
4. Speed - Nowadays with the introduction of the cloud and cloud hosted apps, servers, and the like, there is a reliance on transporting a huge amount of data from our campus network.
5. Planning for the future - Speed directly ties into this. You must always plan for the future. New technologies arise, requiring faster and faster speed and processing of data. Nothing stays the same and your network should be adaptable and be able to accommodate these changes.

Traditional Campus Network Design

In a Traditional Campus Network we typically have two kinds of Cisco Validated Designs (CVDs) that are commonly used. They are the 3 Tier Hierarchy and the Collapsed Core Designs. These are the most common types of Campus Network Designs you would find in a small to medium sized enterprise. There are many components and considerations that goes into creating these specific network designs and as a result there are many benefits but also disadvantages to this approach.

Future Network Requirements

Regardless of Traditional or SDA Network Design, there are a few Cisco and my own personal recommendations for planning for the future. Apply and change based on your own situation. See the below in no particular order:

• Wi-FI 6 & 7 standards need to be supported. There should be a network in place that can support these standards of speeds without having to rip out existing cabling to do so. Cisco Meraki is also a powerful tool to cloud manage access points from a central location.
• Deploy PoE switches where possible. Especially for IOT devices.
• For compliance considerations ensure there are enough monitoring tools to capture your networks data analytics through protocols such as SNMP, NetFlow etc. These may be required for Industry certification.
• Be prepared to upgrade network cabling to support 10, 20, 40 or even 100Gbps throughput as the network is developed. New technologies, users, criticality of how much latency in a network is acceptable will factor in on how much throughput you actually require.