Now that US tax day is over, we in the wireless field can get back to focusing on P1: optimizing and maintaining network performance. Keeping your network in good shape is like gardening: if you don’t pull out the weeds, it’ll never look as good as it could. My friend Jim Florwick detailed the gory bits of the 802.11b penalty with its awful lag in efficiency and absolute waste of spectrum. I write today to help give you the steps to act on Jim’s order to stop the madness.
I liken this process to a memorable scene from Monty Python: You must “Bring out yer dead.” However much the first standard insists it’s still alive, let’s all be honest with ourselves: 802.11b is dead.
In memoriam of the first amendment to the IEEE 802.11 wireless networking standard hailing all the way since 1999, 802.11b was superseded by 802.11a and g in 2003 which are much more efficient. 802.11n was available in draft form in 2007 and was ratified in 2009 while 802.11ac was ratified last September. A few years from now we should be planning the wake for 802.11a and 802.11g as well.
Now is the right time to bury 802.11b and reduce the drag on your network. Let’s be real: there is a reason cyclists are not allowed on the freeway, and an 802.11b device will slow everyone down. Here are 5 easy steps for eradicating your network of 802.11b and getting on your way towards higher speed wireless:
STEP 1. Identify any 802.11b devices on your network
All of the latest Wi-Fi connecting devices are 802.11a/b/g/n capable. So how do you hunt down the 802.11b-only devices? You’ll be looking for older laptop and mobile clients (mostly before the year 2005).
Cisco Prime Infrastructure makes this easy for you with a report on clients by protocol. It will look like this:
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Tags: 802.11, 802.11ac, 802.11b, adapter, Cisco, clients, computer, controller, data, device, gigabit, high density, LAN, legacy, mbps, mobile, mobility, monty python, network, optimize, parameter, performance, phone, rate, smartphone, Speed, tablet, tax, technology, USB, wi-fi, wifi, wireless, wlan, WLC
Live Webinar on 802.11ac in Healthcare July 16, 10am | Register Now
With any new wireless technology, much of what is initially written in the first year is usually focused around the bits and bytes and the speeds and feeds of the technology. This is true for 802.11ac where any Google search will yield a plethora of articles on the potential of Gigabit wireless or that it runs on the 5GHz band and could have up to 8 spatial streams. However, the conversations must start moving towards discussing how the technology can be used in practical situations. In the case of our 802.11ac Module for the 3600, we feel very strongly that it is necessary to not only talk about the speeds and feeds of 802.11ac, but also show how a customer plans to use 802.11ac.
That’s why at our popular presentation at Cisco Live! Orlando, we first discussed the 802.11ac Standard, Cisco’s 802.11ac solution and how it can be used in various networks, and then invited representatives from Methodist Hospital in Houston, TX to discuss their experience to date with 802.11ac. Read More »
Tags: #80211ac, 11ac, 5G, 802.11ac, Cisco, feed, gigabit, healthcare, mobile, mobility, network, Speed, technology, wi-fi, wifi, wireless
Welcome back as we continue to dive deeper into advanced CPU (Central Processing Unit -- I had a “tech writer” change a document on me one time, he assumed at this day in age that people still needed to have the CPU acronym translated.. but I digress) and Memory concepts in the land of VDI. Last week Doron answered our first question and told us about Core Count vs. Core Speed for scalable VDI. This week we will focus specifically on Core Speed, bursting and introduce you to a potentially new subject called “SPEC Blend/Core” for high performance VDI. If you are just finding this blog post for the first time, I encourage you to check out the Introduction from Tony as it will help set the stage for our discussion. Here is the full table of contents:
- Introduction – VDI – The Questions you didn’t ask (but really should)
- VDI “The Missing Questions” #1: Core Count vs. Core Speed
- VDI “The Missing Questions” #2: Core Speed Scaling (Burst) YOU ARE HERE!
- VDI “The Missing Questions” #3: Realistic Virtual Desktop Limits
- VDI “The Missing Questions” #4: How much SPECint is enough
- VDI “The Missing Questions” #5: How does 1vCPU scale compared to 2vCPU’s?
- VDI “The Missing Questions” #6: What do you really gain from a 2vCPU virtual desktop?
- VDI “The Missing Questions” #7: How memory bus speed affects scale
- VDI “The Missing Questions” #8: How does memory density affect VDI scalability?
- VDI “The Missing Questions” #9: How many storage IOPs?
You are Invited! If you’ve been enjoying our blog series, please join us for a free webinar discussing the VDI Missing Questions, with Tony, Doron, Shawn and Jason! Access the webinar here!
VM’s are only as fast as their individual cores! Lets look at what this statement means. Example: Assume we have a 1GHz x 4 core processor (hey, it makes math easy for me). When we carve up a server VM or in this case a VM to be used for VDI, we can’t just give it 2 vCPU’s and say it’s got a 2GHz processor. The reality is that it has a dual 1GHz processor. This becomes an important concept in VDI when you are considering the quantity and QUALITY of vCPU’s you allocate to a Virtual Machine and ultimately the end user applications efficiency and the overall scalability of the server platform. This is not a Uni-processor vs. Multi-processor application discussion. We could easily have a very long discussion and debate on the in’s and out’s of application level efficiencies and the Operating Systems ability (and sometimes inability) to properly manage multiple CPU’s. We are going to expand upon the two CPU’s we tested and dig into per core performance.
CPU Burst vs. CPU Reservation. Let’s play around with our example 1GHz x 4 Core Processor a bit more. If we take this single processor and deploy 8 single vCPU desktops on it we will have a 500MHz CPU reservation per VM. The calculation for that is simple 1GHz x 4 Cores = 4,000MHz / 8 total VM’s = 500MHz/VM Reservation. So the Reservation is simply the average amount of CPU that is available to each VM (assuming everything is prioritized equally). But our Burst is different. Our Burst represents the maximum amount of CPU Core that any one VM could ever utilize. In this example, the Burst per VM is equivalent to 1GHz.
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Tags: Burst, Cisco, desktop virtualization, performances, Speed, vdi