If you’re reading this, chances are you’re either a network engineer, IT manager, or someone tasked with designing a reliable, high-performance wired network—whether that’s for a corporate office, a retail chain with dozens of stores, a smart building, or an industrial facility. And if that’s the case, you’ve probably stumbled across the POE-432EM, our flagship 48-port PoE+ managed switch that’s become a go-to for teams needing to power and connect devices like IP cameras, Wi-Fi 6 access points, VoIP phones, and IoT sensors all in one rack-mountable unit. Over the past few years, I’ve fielded hundreds of questions about this switch from customers, and one of the most consistent ones is: What is the MAC address table size of the POE-432EM? POE-432EM
This isn’t a trivial question. The MAC address table—sometimes called the content addressable memory (CAM) table—isn’t just a random spec number to throw on a datasheet. It’s the backbone of how the POE-432EM forwards traffic efficiently. When a switch receives a data frame, it checks the frame’s source MAC address and maps it to the specific port it arrived on, storing that entry in the MAC table. When it needs to send a frame to a destination MAC, it references the table to know which port to forward it out to, instead of blasting the frame out every port (which would cause unnecessary traffic, slow down your network, and even lead to broadcast storms).
If your network has a lot of devices, or if you’re planning to scale it soon, the size of that table directly impacts performance. A table that’s too small will cause what’s called a CAM table overflow: when the number of unique MAC addresses connected to the switch exceeds the table’s capacity, the switch has to start deleting old entries to make room for new ones, leading to dropped frames, retransmissions, and spotty connectivity. That’s the last thing anyone wants when they’re relying on that network to run core business operations.
So, to cut to the chase: the POE-432EM has a MAC address table size of 32,000 unique MAC addresses. But I don’t just want to throw that number at you and move on—let me break down why that number is exactly what it is, how it works with the POE-432EM’s design, and why it’s tailored to the kinds of networks our customers build.
First, let’s put that 32,000 number in context. A lot of people ask me, “Is that enough?” The short answer is: for nearly all use cases where the POE-432EM is the ideal switch, absolutely. Let’s do the math. A small to mid-sized office might have 50 VoIP phones, 20 Wi-Fi access points, 10 desktop computers, 5 printers, and 10 IP cameras—That’s 95 unique devices, nowhere near 32,000. Even a medium-sized retail store with 100 cameras, 15 Wi-Fi APs, 30 POS terminals, and 20 staff laptops is looking at around 165 devices, still a fraction of the table’s capacity.
But wait, what if you’re running a larger network, or a network with more “hidden” MAC addresses? That’s where it gets interesting. The POE-432EM has 48 RJ45 PoE+ ports and 4 additional 10G SFP+ uplink ports. Those uplink ports connect to core switches, distribution switches, or fiber links to extend your network. Each uplink port can have its own set of MAC addresses from devices on the other end. But beyond that, managed switches like the POE-432EM also support features like VLANs, link aggregation (LACP), and virtual interfaces—each of these can add additional MAC addresses that get stored in the CAM table.
For example, if you have a network segmented into 10 VLANs, each VLAN has its own set of MAC addresses for devices on that segment, so the table doesn’t just count physical port MACs—it counts MACs across all VLANs. Or if you use VLAN trunking on an uplink port, that uplink can carry traffic for dozens of VLANs, each adding their own MAC addresses. That’s why the total table size is 32,000, not 48, a common misconception I run into a lot. A lot of customers assume a switch’s MAC table is equal to the number of ports, but that’s not how it works for managed switches that support multiple VLANs and trunking.
Now, why did we land on 32,000 for the POE-432EM specifically, instead of a larger number like 64,000 or 128,000? We designed the POE-432EM to be a balance of performance, power efficiency, and cost. I know a lot of tech companies jack up spec numbers to look more impressive, but that’s not how we do things. Adding a bigger CAM table would mean more expensive memory chips, which would drive up the switch’s cost for our customers, and for what? The vast majority of our target users never come close to hitting 32,000 MAC addresses. The extra money spent on a larger table would be wasted on a feature no one would ever use. That’s the kind of unnecessary bloat we refuse to build into our products.
But don’t take my word for it—let’s talk about the kinds of scenarios where 32,000 MAC addresses matter, and when you might need to look for a larger table. For example, a large campus with hundreds of buildings connected by fiber links, or a data center edge switch supporting hundreds of servers and virtual machines. Virtual machines are a big one—each VM has its own MAC address, so a single physical server running 10 VMs would add 10 entries to the MAC table, not one. But even then, most edge switches for data centers have dedicated uplink modules, and if you need a higher MAC count, we do offer higher-capacity models in our portfolio, designed specifically for those use cases. The POE-432EM is built for edge networks, not core data centers, so 32,000 is exactly the sweet spot for that role.
Another common question I get is: How does the POE-432EM handle MAC address aging? That’s a key part of how the MAC table works, even if it’s not a spec number. When a device disconnects from the network, its MAC address entry stays in the table for a set period (default is 300 seconds, or 5 minutes) before being aged out. That gives time for temporary disruptions, like a laptop that’s disconnected and reconnected quickly, without deleting and re-adding the entry. If the table gets full, the switch will age out inactive entries first, so you don’t have to worry about dropping valid entries from active devices—unless the number of active devices exceeds 32,000, which as I said earlier, is extremely rare for the POE-432EM’s intended use.
I also want to address a recent feedback I got from a customer who was upgrading their network. They had an older switch with a 16,000 MAC table, and when they added 20 more IP cameras for a new warehouse, they started seeing CAM overflow errors. They upgraded to the POE-432EM, and that fixed the issue immediately. That’s exactly the kind of problem this spec is designed to solve. The older switch just didn’t have enough capacity to handle the number of devices they needed to connect, and the POE-432EM’s 32,000 table was exactly what they needed to scale without overpaying.
One thing I make sure all our customers understand is that the MAC table size is just one part of the POE-432EM’s overall performance, and we don’t hide that. Our datasheets and product guides clearly list the 32,000 MAC address size, along with every other spec, because transparency is something we pride ourselves on. I’ve seen other switch companies downplay their MAC table size, or bundle it with other specs to make it look more impressive, but we never do that. If you need to know a detail, it’s right there for you to see.
Let’s also connect this to the POE part of the POE-432EM, because the “POE” in the name is a big part of why customers choose it. 48 ports of PoE+ mean you can power high-bandwidth devices like Wi-Fi 6 APs, 4K IP cameras, and edge compute devices without needing separate power cables. Each port delivers up to 30 watts, and the switch has a total power budget of 740 watts, so you can power all those devices without worrying about overloading the power supply. And all that power and 10G uplink speed pairs perfectly with the 32,000 MAC table: you’re not just connecting a lot of devices, you’re forwarding traffic smoothly between all of them, without the bottlenecks that come with a small MAC table.
Now, I know some of you might be thinking, “What if my network is growing fast?” If you’re a startup expanding your office over the next two years, or a retail chain adding more locations, the POE-432EM has enough MAC table capacity to handle that growth. Even if you add 100 devices a year, it would take 30 years to hit 32,000. That’s more than enough for most small to medium businesses for their entire lifecycle of using this switch.
I also want to dispel a myth I see online sometimes: that a higher MAC table size automatically means a better switch. That’s not true. A switch’s performance depends on a lot of factors: forwarding rate, buffer size, power efficiency, reliability, and of course, MAC table size. A 128,000 MAC table on a switch that has a lower forwarding rate, or fewer PoE ports, is useless for someone who just needs a reliable switch for 200 devices. We design every product to solve specific problems, and for the POE-432EM, the problem is “connect and power up to hundreds of devices in edge networks, without breaking the bank.” A 32,000 MAC table is exactly the right fit for that problem.
If you’re still here, chances are you’re evaluating the POE-432EM for your next network project, or you’re just curious about how these switches work. Either way, I’m happy to answer any other questions you have—whether it’s about the MAC table, PoE performance, uplink capabilities, or anything else related to our products. Our team works with businesses of all sizes, from small offices to large enterprises, and we can help you figure out if the POE-432EM is the right fit for your needs, or if another one of our products would be better.
POE-432EM If you’re ready to move forward, reach out to our team to discuss your specific requirements—we can talk about how the POE-432EM’s MAC table, power budget, and other features will work for your network, answer any follow-up questions, and walk you through procurement. Don’t hesitate to connect with us to get the support you need to build a reliable, high-performance network.
References
- Cisco Systems, Inc. (2022). Cisco Catalyst 9200 Series Switches Data Sheet.
- IEEE 802.1AB-2016. Station and Media Access Control Connectivity Discovery (LLDP).
- Network World. (2021). “How MAC Address Table Size Impacts Switch Performance”.
- POE-432EM Product Datasheet. Our company, 2024.
- Jung, S., et al. (2020). “Scalable MAC Address Table Design for Managed Ethernet Switches”. IEEE Transactions on Networking.
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