Switching and Wi-Fi have driven continuous changes in networking. Without going through the history of network technology, most would agree that the speeds of wired products (10/100/1000 Mbps and now 2.5/5/10/40/100 Gbps) and the ability to provide power (Power over Ethernet) has been a boon to end points such as wireless access points. While in the wireless end of things, increased demand for power, speed, higher density client support as well as changing protocols, continues to demand more from the wired infrastructure. And more technology is coming to our networks such as digital signage, internet of things (both wired and wireless), converged VoIP, IPTV and Over the Top Content to name a few. Therefore, reviewing the trends and technologies of wired and wireless is critical, with the understanding that planning and budget cycles must be equipped to get the best out of both.
Wi-Fi: Throughput and Power
In enterprise facilities, hotel guest rooms, public venues, we can all agree that wireless (Wi-Fi in most cases) is the most used on-ramp to the network and internet. The Wi-Fi Access Point with its wired connection to the network provides that access. Access Points (AP) have evolved over the years with supported protocols (802.11a/b/g/n/11ac/11ac-w2/11ax), number of transmit and receive chains per radio, number of radios, and additional services such as USB, BLE and more. The Wi-Fi AP has become a very sophisticated networking device, if you review of the datasheets for the UAP-XG and UWB-XG from Ubiquiti Networks, you will find examples of multiple radios running the latest protocol with support for high density client devices.
Throughput speed demanded from a single Access Point has gone up over the years but has stayed under the 1 GigE limit (see https://store.ubnt.com/blogs/news/when-will-we-hit-the-limits-of-gigabit-ethernet-with-wi-fi ). There are several reasons why current Wi-Fi does not require multiple gigabits of throughput with spectrum efficiency being at the top. However, as the technology moves to 3 and 4 radios per AP, as 802.11ax (with its many spectrum improvements), plus other services such as BLE (Bluetooth Low Energy) in the AP, come to market clearly there is a need for multi-gigabit APs. More and more, the market is introducing APs with multigig uplinks; 2.5/5 and 10 Gbps (Ubiquiti’s UAP-XG and UWB-XG both run 1/10 Gbps).
Multi-gig will offer great benefit to places where thousands of people are likely to gather, but there is a reality check worth mentioning. When 1 Gbps switches first hit the market, there was a premium on price. Multi-gig will be the same, and just like their predecessor the cost will drop as their implementation grows over time. Multi-gig speeds will not be required everywhere but places like large conference rooms/stadiums and more will benefit from the increased throughput speed.
Another clear trend with Access Points has been the need to require more electric power to run. APs have moved from requiring the 15.4W (IEEE 802.3af) of Power over Ethernet with 802.11b/g/n to requiring 30W (802.3at), 51W (802.3bt type 1), and even 71W (802.3bt type 2)! (Please see Wiki on Power over Ethernet https://en.wikipedia.org/wiki/Power_over_Ethernet for background). The Wi-Fi standard 802.11ax (coming late 2018 and into 2019) will have Access Points with eight radios and will most likely require 802.3bt power to operate. Access Point technology, or more generally wireless connection points, will continue to evolve and it is safe to say power demands will increase.
Switching: Throughput and Power
In this section, we will want to look at the connection from switch to single AP, switch to many APs, and switch to the core networking switch; i.e. the classic trunk and branch network architecture. Oversubscribing, ingress bandwidth is greater than the egress bandwidth, links in a network is common and an excepted practice. But it is always critical to make sure that the total network throughput is keeping up with demand by reviewing AP to switch and switch to switch connections.
Image from Ubiquiti Unifi Software
Access Points now have multi-gigabit uplink ports that allow for 2.5/5/10 gigabit connections with a single cable (i.e. not using two 1 gig and LACP). So though not required by many APs from a pure throughput perspective today, a single AP can be connected to a switch port with matching multi-gig functions and create a 2.5/5/10 gig connection. An example where this could be important is deploying an AP like the Ubiquiti UWB-XG in a stadium or hotel conference room; the 3 x 5GHz 802.11ac W2 radios and hundreds of clients will benefit from non-blocking throughput to the switch.
When you have a switch populated with Access Points, even at 1Gig per port, the downlink to the Core Switch will almost always be oversubscribed; i.e. a 24-port switch with 24 APs pushing 200 Mbps per AP would be 4.8 Gig of traffic, more then a 1Gig or 2Gig connection can handle between switches. Plus, with higher speed, next-gen APs the problem gets worse. Luckily, cost effective switch support for 10/40/100 Gigabit has arrived and is now allowing for very fast switch to switch core networking. So, the recommendation is not to run out and create a completely non-blocking switch infrastructure but to predict your network throughput requirements for the long term and be aware of the possibilities with ethernet switches.
Powering the many devices in our lives and facilities is daunting; luckily the technology is advancing in batteries, green savings, and efficiency. As discussed above, switches with power over ethernet has been critical to our modern network and convenient with a single data/power cable for so many devices. The PoE standards (Wiki Link above and table below) in switch technology has advanced with the latest being 802.3bt.
|Property||802.3af (802.3at Type 1)”PoE”||802.3at Type 2 “PoE+”||802.3bt Type 3 “4PPoE”||802.3bt Type 4|
|Power available at PD||12.95 W||25.50 W||51 W||71 W|
|Maximum power delivered by PSE||15.40 W||30.0 W||60 W||100 W|
When considering a switch, power features are as critical as throughput for edge switches connecting to powered devices. It is critical to look at the overall power budget provided by a switch, whether it can accept additional power through power device, and the breakdown by port of power features. For example; a switch could have 750W total available power, 48 gig ports with all 48 ports capability of 802.3at and 8 ports capable of 803.3bt plus SFP+ or QSFP ports for 10 gig uplinks or more. The important thing to note is all ports share the 750W power.
Bringing it all together with network design, planning and budget
Clearly, there is a natural one-upmanship that occurs between wired and wireless equipment on your network. They each evolve in processing speed, though-put, and power (required by AP and provided by the switch). The key for any IT Manager is to navigate the technology growth in wireless and wired with careful planning and foresight to budget and purchases across multiple cycles and years. For example; working with a Hotelier that wanted to upgrade their 802.11ac W1 APs in their conference room to 802.11ac W2 while continuing to run on 24 port switches with 1 gig uplink, 1 gig and 802.3af per port. The IT Manager instead upgraded his switches to 10 gig uplink switches, some multi-gig ports and 802.3at per port with some number of ports allowing for 802.3bt. He will upgrade the APs within the coming years but his switch infrastructure is better prepared for those future access points.
Whether implementing a new network or updating an existing network, careful planning for both wireless and wired is as important as ever. New products and technologies have come to both access points and switches that are critical to include in your network today and for the future.
by Matthew FitzGerald 9
Matthew FitzGerald is Senior Hospitality Solution Architect at Ubiquiti Networks
Matthew FitzGerald is a Hospitality IT Professional with deep background in Wi-Fi. Matthew has contributed to published documents on PCI, Hotspot 2.0 as well as Wi-Fi principals and trends. His work with partners, brands and organizations in the Hospitality Industry range from the design, deployment, testing and planning for future goals of hotel networking and technologies. Matthew continues to work with organizations to understand the changing switching and Wi-Fi landscape and to create best practices to address current and changing requirements.