Network edge switch upgrades hinge on WLAN deployments

Everyone is used to the analogy of networks and plumbing: those pipes in every building that are invisible, yet mission-critical.

No element in the contemporary network fits this correlation better than the Ethernet switch -- it's ubiquitous, but invisible to almost everyone. Switches perform a variety of roles, among them interconnecting devices, like printers and servers and wireless access points (APs); providing electrical power as required; and implementing security and traffic-flow mechanisms.

Edge switches converge to core switches in data centers that eventually meet up with the routers that connect to the WAN. In operation, switches are vital, but invisible to almost everyone except the plumbers -- I mean, network operations professionals.

Those folks get very interested in switches, particularly network switch edge devices, when increasing network loads, geographic growth or advances in network technology -- usually per-port throughput -- dictate an upgrade. As WLAN speeds and capabilities continue to increase, there are a number of decisions required when determining if it's time to upgrade your edge switches to support your WLAN deployments, including the following:

Port count and physical space. There is a good chance you're going to need more switch ports over time as the number of APs increases to keep up with demands from users and as more internet-of-things devices are connected to the network. An upgrade at the edge is fairly easy to manage with stackable switches, but also be aware of any new space, power and cooling requirements.

Depending on the selected network edge switch, we also suggest considering port modularity implemented via small form-factor pluggable transceivers, which can, in many cases, enable the evolution of wire plants without the need for wholesale switch replacements.

Management. Compatibility with the local management and analytics console is always important. Sure, we still have the mix-and-match interoperability central to Ethernet, but multiple management consoles and databases can create situations where performance actually suffers -- to say nothing of potential glitches occurring as a result of unintended incompatibilities. 

Power over Ethernet. New network edge switch devices should support 802.3at and even the upcoming 802.3bt standard, rather than 802.3af and any vendor-proprietary PoE schemes in order to ensure sufficient power is always available.

Throughput and capacity. It's reasonably easy with modern management consoles to identify any bottlenecks occurring at switch ports. Keep in mind, though, that newer Wi-Fi standards -- 802.11ac Wave 2 and going forward from there -- can exceed per-link media access control throughput of 1 Gbps. While link aggregation is a common answer here, it seems likely that 10 Gbps, and perhaps even 100 Gbps, at the edge will become a WLAN deployment requirement over the next three to five years in many shops.

The wiring question. New standards for 2.5 Gbps and 5 Gbps Ethernet have been developed with a simple goal in mind: Exceed 1 Gbps on an individual switch port, but do so via existing CAT5e (2.5 Gbps) or CAT6 (5 Gbps) cabling. While new switches are still required in this case, new cabling -- presumably the CAT6A specified for 10 Gbps -- is not. So, is this form of network edge switch upgrade a good idea? That depends.

It's a good bet 2.5 Gbps and 5 Gbps should hold us through the current generation of APs, but what about 802.11ax and .11ay? Both of these will likely exceed 5 Gbps, so the decision to not upgrade wiring may be good for only a few years -- and by then, the labor cost of installing new wire could be significantly higher.

On the other hand, fiber to the AP -- with integrated copper for power -- may ultimately be the best approach. So, even installing CAT6A might not be optimal for WLAN deployments over the long term. But, then again, it might, as 10 Gbps should provision plenty of capacity for many, if not most, organizations for many years to come.

We also suggest trying older cabling at higher signaling rates; this approach often works reasonably well, especially with shorter cable runs. For now, though, there really is no easy answer here. Note also that upgrades to core switches, which are today typically 10 Gbps and up, may also be required.