--- title: Software-Defined Networking (SDN) Explained Simply description: "Software-defined networking explained: the challenges SDN solves, how it separates control from network devices, and what it means for campus networks." image: https://blog.iptel.com.au/hubfs/Blogs/Software%20Defined%20Networking/Software%20Defined%20Networking%20Explained.png --- [![IPTellogo-byline-2020-dark-v2-pnd-optimised-500 (1)](https://blog.iptel.com.au/hs-fs/hubfs/IPTellogo-byline-2020-dark-v2-pnd-optimised-500%20(1).png?width=200&height=59&name=IPTellogo-byline-2020-dark-v2-pnd-optimised-500%20(1).png "IPTellogo-byline-2020-dark-v2-pnd-optimised-500 (1)")](https://iptel.com.au) - [Home](https://iptel.com.au/) - [Solutions](https://iptel.com.au/solutions) Technologies - [Cisco Access Manager](https://iptel.com.au/technologies/cisco-access-manager) - [Cisco Catalyst Center](https://iptel.com.au/technologies/cisco-catalyst-center) - [Cisco Meraki](https://iptel.com.au/technologies/cisco-meraki) - [Cisco SDA Fabric](https://iptel.com.au/technologies/cisco-sda-fabric) - 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[Request a Quote](https://iptel.com.au/request-a-quote) - [Managed Services](https://iptel.com.au/managed-services-enquiry) Case Studies - [DP World Video](https://blog.iptel.com.au/hubfs/Case%20Studies/DP%20World_Case_Study.mp4) - [DP World](https://blog.iptel.com.au/dp-world-case-study) - [Backup Assure](https://blog.iptel.com.au/backup-assure-a-disaster-recovery-case-study) [Contact Us](https://iptel.com.au/contact-us) This is a search field with an auto-suggest feature attached. - There are no suggestions because the search field is empty. ## Software Defined Networking: Explained Oct 2, 2025 There are multiple challenges in designing, deploying and maintaining a network environment. We can’t go through all these in one blog - there are just too many, but in this blog, we’re going to have a quick run through on those that SDN (Software Defined Networking) can help solve.  ![Software Defined Networking Explained](https://blog.iptel.com.au/hs-fs/hubfs/Blogs/Software%20Defined%20Networking/Software%20Defined%20Networking%20Explained.png?width=1229&height=658&name=Software%20Defined%20Networking%20Explained.png) First up, I'm going to be talking about SDN in a Wi-Fi centric environment. Cisco calls this SDA (Software-Defined Access, or SD-Access). There's a lot of 'Software Defined' everything out there, from generic SDN to the Cisco SDA. [SDA Fabric](https://blog.iptel.com.au/what-is-sda-fabric)is also a term we're all going to be hearing a lot more about - and the topics of [Macro and Micro Segmentation](https://blog.iptel.com.au/blog/cisco-sd-access-micro-segmentation-explained). Anyway - to set the scene - we'll be talking about Cisco SDA and the use of Cisco Catalyst Center (formerly Cisco DNA Center) in the implementation of your Wi-Fi network. If you're interested in an entry level blog, have a read of [Cisco SD Access Demystified.](https://blog.iptel.com.au/blog/cisco-sd-access-demystified) Related reading - [Cisco Catalyst Center Beginners Guide](https://blog.iptel.com.au/cisco-catalyst-center-beginners-guide) - [The CIO's guide to Cisco SDA](https://blog.iptel.com.au/the-cios-guide-to-cisco-sda-fabric) --- ## Network Challenges Looking after any network comes with its range of challenges. Let's take a quick look at a list: - **Security:** Secure on-boarding for new clients - **Complex:** Wi-Fi is complex to manage - **Time Consuming:** Issues with Wi-Fi are slow to resolve To make matters that bit worse, design for WLAN is also a little complex – involving up front allocation of SSIDs, VLANs and IP Address ranges. Added to this, the factors and complexity that RF design and fault finding bring, you can see that a large, centralised WLAN environment needs some special skills to be able to deploy and operate. This is of course typically [where we come in.](https://iptel.com.au/contact-us) However, with the advent of SDA, it's getting simpler – to a point. Let’s take a look at why.  Related reading - [Catalyst Center Beginners Guide](https://blog.iptel.com.au/cisco-catalyst-center-beginners-guide) --- ### Advantages of Software Defined Access Software Defined Access has some key advantages, including:  - **Identity Based:** Based around how you deal with the client, not around the VLAN, IP ranges and so on - **Automated Network Fabric:** Making configuration quicker and easier - **Insights and Telemetry:** Can automatically capture logs and sniffs for easier fault finding There’s a bit in these above points to dissect, so let’s take a closer look.  Related reading - [How to Build an SDA Fabric Lab: Part 1](https://blog.iptel.com.au/cisco-sd-access-lab-part-1) - [How to Build an SDA Fabric Lab: Part 2](https://blog.iptel.com.au/cisco-sd-access-lab-part-2) --- ### Identity Based Access Cisco ISE plays a big part in the authentication of users and devices on a network. Check out the [Top 5 Unique Features of Cisco ISE](https://blog.iptel.com.au/why-cisco-ise). [![Cisco ISE Support 1](https://blog.iptel.com.au/hs-fs/hubfs/Campaigns/Cisco%20ISE/Cisco%20ISE%20Upgrade/Cisco%20ISE%20Support%201.png?width=197&height=197&name=Cisco%20ISE%20Support%201.png)](https://info.iptel.com.au/request-a-quote)You will now identify a user / device and provide a network experience tailored to that user. This is a pretty big change in concept to how we’ve always worked. You can micro-segment individual clients and be very specific on what access they have and automate the whole process. No longer do you need to deal with placing clients in VLANs, but just in tagging them with the attributes they will experience within the network – more on this in the next point below.  Related reading - [Cisco Catalyst Center Enablement](https://blog.iptel.com.au/cisco-catalyst-center-enablement) --- ### Automated Network Fabric The expression ‘fabric’ seems to crop up quite a lot these days and in this regard, we are talking about the ability to fully control the network from Cisco Catalyst Center. This means a routing underlay is applied, all network elements can communicate and we apply the network overlay to give the client the network experience. This is tied in with the point above – we need strong Identity Based controls to allocate the right network experience to the right client. The automated Fabric allows us to set up Contracts, which are then automatically applied to clients.  --- ### Insights and Telemetry A network that uses Artificial Intelligence (AI) can do that much more than a standard network management station which just alerts based on static alarms. Telemetry means we are getting continuous data from network elements, so we have the most up to date data, with which to make informed decisions.  Related reading - [Cisco Spaces Introduction](https://blog.iptel.com.au/cisco-dna-spaces) --- ### Why SD Access? We’ve had a run through the advantages of SDA above, but what reasons might you use when you go speak with your boss and try to convince them to invest in SDA? Let’s take a look:  - **Automation:** Automation and Programmability - **Mobility:** Host Mobility - **Policy:** Policy Simplification The above concepts are in many ways all part of the same key point. SDA is a whole new world, where we have clients connect wherever they want to and we can micro-segment their access between these clients and other clients. We can implement much greater control, but also simplify a vast array of rules and regulations on that client’s access.  This is essentially a policy model and the whole process is about simplification of the network attributes – IP ranges, VLANs, QoS, Security, etc – this is now based on identity of the end user / device, not the DSCP values or TCP ports in use.  The policy model then moves from an IP level up to an identity level.  Related reading - [Troubleshooting with Catalyst Center](https://blog.iptel.com.au/troubleshooting-with-cisco-catalyst-center) - [Cisco Catalyst Center Assurance](https://blog.iptel.com.au/blog/cisco-catalyst-center-assurance) - [5 Ways Catalyst Center Solves your Challenges](https://info.iptel.com.au/cisco-dna) --- ### SDA Explained: Summary The key concept to take away from this blog is that the world is changing from one where we determine how a client is treated on a network based on the VLAN, TCP / UDP ports in use or DSCP markers placed on the packet, to one where we act based on the identity of the client.  We understand the client and the required attributes and the network implements these under the surface – this is much more secure and a much greater granular control can be applied.   It’s a completely different concept of course from our historic network configurations of per-hop based QoS, so it will be interesting to see how the adoption and uptake of SDA happens.  Related reading - [Cisco AI Analytics in operation](https://blog.iptel.com.au/cisco-ai-analytics-in-operation) - [Cisco Machine Learning and AI](https://blog.iptel.com.au/cisco-machine-learning-and-ai) --- #### Need Help? If you’re looking for a partner to help you through the future of networking – or to just help you design your Wi-Fi coverage, [visit our Contact Page,](https://iptel.com.au/contact-us) or drop us a line to [sales@iptel.com.au](mailto:sales@iptel.com.au)   We are experts in network design and especially Wi-Fi design and remediation. Catalyst Center and SDA are new specialties for us – if you need help, drop us a line.  --- ## Software-Defined Networking: FAQs ### What Is Software-Defined Networking? Software-defined networking (SDN) separates the decisions about how a network behaves from the devices that forward traffic. A central controller defines policy and pushes it to the network, instead of each device being configured by hand. ### What Are the Benefits of SDN? SDN makes networks faster to change, more consistent and easier to secure, because policy is defined once and applied everywhere. It also gives better visibility into how the network is performing. ### What Is Cisco's Version of SDN for Campus Networks? For campus networks, Cisco SD-Access uses Catalyst Center as the controller and Cisco ISE for policy. For the WAN, Cisco SD-WAN and Meraki SD-WAN apply the same idea. ### Is SDN Only for Large Organisations? No. Cloud-managed platforms such as Meraki bring many SDN benefits, such as central policy and zero-touch deployment, to smaller organisations too. ### Need Help With Software-Defined Networking? IPTel designs and deploys [Cisco SD-Access](https://iptel.com.au/technologies/cisco-sda-fabric) and SD-WAN for Australian organisations. If that would be useful, [get in touch with the IPTel team](https://iptel.com.au/contact-us) or email [sales@iptel.com.au](mailto:sales@iptel.com.au). #### Related Articles ###### [Cisco SDA Migration](https://blog.iptel.com.au/cisco-sda-migration) Mar 31, 2026 ###### [What is Cisco SDA Fabric?](https://blog.iptel.com.au/what-is-sda-fabric) Oct 18, 2025 ###### [Cisco SD Access: Micro Segmentation Explained](https://blog.iptel.com.au/blog/cisco-sd-access-micro-segmentation-explained) May 9, 2025 Free tool ### How Many Wi-Fi Access Points Do You Need? Work out APs, PoE and switch ports floor by floor, using the same survey grades our Cisco wireless engineers design to. Takes under a minute. [Try the AP Estimator →](https://iptel.com.au/resources/wifi-access-point-estimator?utm_source=blog&utm_medium=cta&utm_campaign=ap-estimator) ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "IPTel Solutions", "url" : "https://blog.iptel.com.au/author/iptel-solutions" }, "dateModified" : "2026-10-03T07:44:28.394Z", "datePublished" : "2025-10-02T03:16:09.000Z", "headline" : "Software-Defined Networking (SDN) Explained Simply", "image" : [ "https://blog.iptel.com.au/hubfs/Blogs/Software%20Defined%20Networking/Software%20Defined%20Networking%20Explained.png" ], "mainEntityOfPage" : { "@id" : "https://blog.iptel.com.au/software-defined-networking", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://blog.iptel.com.au/hubfs/IPTel_Solutions_February2020%20-%20Header%20SiteMap/Images/IPTellogo-byline-2020-dark-v2.png" }, "name" : "IPTel Solutions Pty Ltd" } } ```