My Apple & Raspberry Pi(e)

Apologies for the appalling title of this blog post, but hey, you're here! :) In this post I talk about my purchase of a Raspberry Pi (by devious means) and how I set it up as an iPerf server. I have recently been reading lots about the Raspberry Pi mini/micro/teeny-weeny ( I don't know what the correct term is...) single board computer, which has been created by the Raspberry Pi Foundation in a attempt to promote the teaching of basic computer science in schools (according to Wikipedia ). I've been itching to get my hands on one for a while and finally came up with a great excuse to buy one and have a play with it. They're incredibly cheap (around £30 for the basic computer board), so I concocted a flimsy excuse about buying one to teach my son about computing. After letting him play with it (and get bored) for about 30 minutes, I quickly slipped in to my home lab where I will no doubt continue to 'evaluate' it. The Pi is supplied with a flavour of Debia

Adjacent Channel Interference

I was inspired to try a bit of experimentation following Keith Parsons' recent WiFi stress testing sessions, where he conducted testing on a number of vendor APs to observe at what point they collapsed in to a heap  due to traffic throughput. I can't carry out anything as grand or detailed as Keith (I don't have his knowledege, brains or resources!), but I thought it might be fun to test some de-facto rules around the use of the 2.4GHz band for WiFi. In summary, due to the bandwidth requirements of WiFi equipment, it recommended that the spacing of at least 22MHz is allowed between the channels being used in the 2.4GHz band. This is required for the bandwidth requirements of the older DSSS modulation scheme. The newer OFDM modulation technique requires only 20MHz of space, but for reasons of backward compatibility, the 22MHz rule persists. The band itself is sliced up in to 11, 13 or 14 channels depending where you are in the world. Each channel is 5MHz in width, as

Aerohive AP121 Alternative Power Supply

Got yourself a free Aerohive 121 AP after a recent training course or webinar? Got it home and found it's got no PSU!? Yeah, annoying isn't it... Get yourself one of these 'bad boys' off Amazon - bought one this week and works a treat! Disclaimer : if it blows your AP up don't blame me...mine certainly worked OK :) *** Update 11th October 2013*** Works well for an AirTight C-55 AP too!

Which iPads Are On The Network?

Sometimes you can walk on to a customer site and the customer may have iPad devices using the WiFi network. They may also have a range of different models, so that it is difficult to perhaps know the WiFi support capabilities available among their devices. In summary, to-date all iPads support 802.11 a/b/g and 802.11n on both the 2.4GHz and 5GHz bands. The 802.11n support is exclusively single stream, but the channel width that can be used has changed with recent models. Both the 4th Gen. iPad and iPad Mini support 40MHz channel widths on the 5GHz band. It is quite difficult to determine which version of iPad you have just by a cursory glance at the device. A very good way of determining the device type you are working with is to check the model number on the back of the iPad. It's a little tricky to read due to the small size of the etched-in font, but with a bit of a squint, you can just about see it. Here is a picture taken from the rear of my own iPad 2: By using t

Cisco 2504 FUS Update for 7.4 Code

" Cisco Unified Wireless Network Field Upgrade Software (FUS), Release, is a special AES package that performs various system-related component upgrades for Cisco Wireless LAN 2500 Series Controllers. If you are using a Cisco 2500 Series Controller and you upgrade to the controller software release and intend to use the Application Visibility and Control (AVC) and NetFlow protocol features, you must install Cisco Unified Wireless Network Field Upgrade Software, Release This release is not required if you are using other controller hardware models." This definitely worth noting if you are upgrading to 7.4, as the new AVC features will not work without it. Also, it is well worth attaching a console cable whilst doing the upgrade as it takes a long time (around 30 minutes). Without the console, you'll be sitting there with your fingers crossed, breaking out

Apple TV Services

I've been taking a look at the Bonjour protocol in general recently due to some requirements I have been looking at for customers. The availability of Bonjour gateways from the likes of Cisco and Aerohive certainly make things a lot easier to provide access to Bonour services without having to jump through lots of multicast-over-wireless hoops. One area of particular focus has been Apple TV. It seems to be quite a popular device with execs who want to be able to mirror their iPad on to a meeting room projector. There are some great tools that allow you to browse the services that are available on a network. I have been using  Bonjour Browser for Windows , though other Mac equivalents are also available. When looking at the services available from an Apple TV, I see the following services advertised: _airplay._tcp. _raop._tcp. _sleep-proxy._udp. _touch-able._tcp. _appletv-v2._tcp I was interested to know what each of these services does. So, here it what I've be

Apple iTunes Services

This is just a quick note about some Apple services you may see advertised using mDNS when you are implementing a Bonjour gateway on your wireless network. I've been investigating which services might be visible when the iTunes application is being run on computers that are connected to the wireless network. From my testing, I have only been able to find 2 services you may come across when using iTunes ( this just considers the iTunes application and does not include any other services from Apple TV, printers etc .): _daap._tcp.local. _apple-mobdev._tcp.local. _daap._tcp.local. This service becomes available when you choose the option to share your library on the local network Share library on local network: The service advertisements are generated by the iTunes software on the computer (and hence originate from the computer itself) to be detected by other devices/computers across the network _apple-mobdev._tcp.local. This service becomes visible when the