Archive › February, 2014

Spanning Tree and OpenFlow

Questions I often get asked include: Can you run Spanning Tree and OpenFlow together? What happens when Spanning Tree blocks a port? What will OpenFlow do? Will not having redundant links in an OpenFlow network result in loops? Firstly, it is possible to run an OpenFlow network connected to the HP VAN SDN Controller with […]


OpenFlow configuration: HP Comware 5500 switches with the HP VAN SDN Controller

HP Comware switches have supported OpenFlow from late 2013 on HP 5900 switches running Comware7. OpenFlow is now also supported on A5500-EI switches running Comware 5.20 release R2221 as well as A5500-HI switches running Comware 5.2 release R5501. The release date for some of this the was last few days of December 2013. Click here […]


Disconnect me – stop websites tracking you

Google are tracking you (and so are many others). This most of us know I am sure. That is how they make their money. But, some of us like our privacy… I have been using a cool privacy and proxy service for a while. To show the differences in Google searches from the where I […]


OpenFlow Datapath ID (DPID)

How are OpenFlow switches identified? Each OpenFlow instance on a switch is identified by a Datapath Identifier. This is a 64 bit number determined as follows according to the OpenFlow specification: “The datapath_id fleld uniquely identifies a datapath. The lower 48 bits are intended for the switch MAC address, while the top 16 bits are […]

OpenFlow on HP Comware switches

OpenFlow configuration: HP Comware 5900 switches with the HP VAN SDN Controller

In this blog entry I’ll show you how to get a basic OpenFlow network working using HP 5900 Comware switches and the HP VAN SDN Controller. HP announced support for OpenFlow on the Comware 5900 series switches towards the end of 2013. The 5900 switches support OpenFlow 1.3.1. These switches require Comware version 7.1 and […]

OpenFlow configuration HP ProVision switches with the HP VAN SDN Controller

OpenFlow configuration: HP ProCurve switches and the HP VAN SDN Controller

In this blog entry I’ll show you how to get a basic OpenFlow network working using HP ProVision switches (formally ProCurve and E-Series)  and the HP VAN SDN Controller. See this blog entry for the configuration of HP Comware switches. See other blog entries for more complicated topologies. This is a simple topology of two 3500yl switches […]


Raspberry PI install with no monitor

Follow these steps to install a Raspberry Pi with no monitor: 1) Format SD Card: Format your SD Card using the SD Formatte 4.0 for SD/SDHC/SDXC: Click on the the “Option” button and change the Format Type to “FULL (Erase)” and Format Size Adjustment to “ON”: Click “OK” and the click “Format” 2) Download […]

Installing VNC on Raspberry Pi

Installing VNC on Raspberry Pi

To configure your Raspberry Pi to support VNC, following these steps: 1) Cable Raspberry Pi: Physically connect the Raspberry Pi to your network using the wired connection. 2) IP address discovery: Find out the IP address of the Raspberry Pi. In this case, my local BT DSL router is set up as a DHCP server […]