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The huge increase in mobile devices used by employees and customers alike is challenging IT organizations' wireless networks. Many C-level execs understand that mobility is a strategic issue and have plans to upgrade their wireless infrastructure. In this webcast presentation, Shamus McGillicuddy, senior analyst for Enterprise Management Associates, explains why a wireless upgrade can create problems on the wired network -- and discusses how to deal with those problems.
Editor's note: The following is a transcript of the third of four parts of McGillicuddy's webcast presentation on enterprise networking strategy to support your users' mobile devices.
See the rest of this webcast presentation
Part 1: Determining enterprise networking strategy to support mobile devices
Part 2: Upgrading the wireless LAN
Part 3: Trickle-down effect on the wired network
Questions about this webcast presentation on how a wireless upgrade impacts the wired network? Email firstname.lastname@example.org.
Transcript - Enterprise mobility’s impact on wired network infrastructures
Shamus McGillicuddy: A wireless upgrade will challenge the wired network in certain ways. Increased mobility has a trickle-down effect on the Ethernet LAN and your WAN links. With more mobile devices, you can expect more traffic because each user will have PCs, smartphones, tablets all hitting your network at once. There's going to be more network flows per user. Also, you [have to] think [of] all [the] Wi-Fi traffic backhauls across the wired LAN to reach things like the wireless controller, your corporate applications, your collaboration tools and the Internet. All that increased traffic that hits your Wi-Fi … [is] going to hit your wired network [too].
So, this means that you may need some switch upgrades in the future. Many closet switches have 1 gigabit Ethernet uplinks to the campus core and with more mobile traffic, those uplinks might get oversubscribed. You may need switches that have 10 gigabit uplinks from the closet. You [have to] talk to your engineers about that. Similarly, with 802.11ac Wave 2 technology, you're going to be moving into multi-gigabit speeds in your wireless and, chances are, most of you at most have 1 gigabit access switch ports to your access points today, which means that your Wave 2 technology, when you invest in it, will exceed the capabilities of the Ethernet ports that you plug them into.
So, you're going to need to upgrade your downlinks to the access point if you go in this direction. There are a couple options right now. Option one: Install switches with 10 gigabit access ports. This is going to probably require you to do cable upgrades because most installations of gigabit Ethernet use cabling that does not work with 10 gigabit at any distance more than a couple meters. Option two: Some vendors are developing 2.5 and 5 gigabit Ethernet switches today. These will use existing Cat 5e cables that are typically used today by your gigabit switches, so you'll not need to do cable upgrades, but you still need to get new switches.
And one thing you need to think about as your engineers are talking about this: The industry standards path for this technology is unclear because there are at least two different vendor groups developing technology in parallel. It probably will work itself out, but you want to talk to vendors about this to make sure that they're toeing the line because interoperability is important.
Other upgrade considerations: 802.11ac access points may exceed the Power over Ethernet budget on your installed switches. Most people power their access points with the Ethernet switches that are configured to deliver electricity through the Ethernet cable. The latest Power over Ethernet standard, 802.3at, delivers 25.5 watts. Full-featured 802.11ac access points will probably require more than that. There are nonstandard implementations of Power over Ethernet that can reach 50 watts from certain switch vendors, so you might want to look at that. Wi-Fi vendors will offer access points with power budgets designed to fit your legacy Power over Ethernet networks, but the features will be limited because they'll have to do things like install fewer radios in the device, which impacts throughput and coverage. Some Wi-Fi vendors will also sell you power injectors that boost the power delivered to your access points through the Ethernet cable, so that can also solve the power problem.
Also keep in mind that your wide-area network links and your Internet circuits may need upgrades. More mobile devices equal more flows and more traffic leaving your local area network. I've talked to many universities and enterprises [that] have had to upgrade the Internet connection after a Wi-Fi upgrade or expansion, especially if a university suddenly adds Wi-Fi to a dorm room for the first time -- all of the kids are going to connect their Xboxes to the wireless network -- and suddenly all of this Xbox traffic is going to hit your Internet circuit and it's going to cause a huge bottleneck.