Posted 31 May 2012 | | 0 Comments
I am one of those industry professionals raised on the BBC Micro. The BBC Micro was one of a number of micro computers developed in the 1980s. It came in two flavours, model A and model B. The model B had a 4 MHz 6502 processor and 32 Kbytes of main memory. Cassette tape was used for secondary storage, though you could get 5 ¼ inch floppy drives. At the time, it cost £400. Contrast this with what you can get for the same amount of money today.
The huge amount of power that is packed in today's computers means they can run highly sophisticated software – much more s...read more
by Alan | 31 May 2012
Posted 3 May 2012 | | 14 Comments
A few weeks ago I wrote a blog article about doing transparent intercept redirection with the Allot NetEnforcer using its 'Traffic Steering' feature. This week, I thought I'd cover off another method of transparent redirect, but this time using some of Juniper's product portfolio, namely the EX switching platform and SRX firewall and, as always, my favourite proxy of choice, a Blue Coat ProxySG.
I've mentioned before, transparent proxy is my preference. With the Blue Coat ProxySG as your proxy,...read more
by Andy | 3 May 2012
Posted 27 April 2012 | | 0 Comments
For some time now, the well regarded SpamHaus global DNS Blacklist system has been helping mail servers to protect against SPAM and other unwanted mail content. It's a mature, autonomous system which allows mail servers to run a Blacklist check against connecting IP addresses to verify their 'trustworthiness' and if found to be untrustworthy (due to previous sending of spam, belonging to a dynamic IP address range which shouldn't' be sending email, etc), the email communication is rejected. Great stuff, 'nuff said. Good work SpamHaus!
There are a large number of othe...read more
by Andy | 27 April 2012
Posted 19 April 2012 | | 6 Comments
A problem fell onto my desk the other day concerning the use of a particular feature on the Allot AC1400 NetEnforcer, Allot’s AOS-based appliance which is a high capacity bandwidth management device that can help network administrators control, manage and above all give visibility to protocols running over network links.
The feature - ‘Traffic Steering’ - is a delightfully simple, yet very useful capability that allows the NetEnforcer to transparently redirect selected traffic to a ‘Service Port’ or designated link and is available on all AOS (Allot Operating Syste...read more
by Andy | 19 April 2012
Posted 8 September 2011 | | 0 Comments
Within the IT industry it has become customary to use the term quality-of-service to mean the management of traffic rather than the some measure of the service level. This has merely become the adopted convention. In this article I drop the established convention “quality-of-service” term in favour of traffic management. Traffic management is applied at the router/switch attempts to optimise network resources. In this article, we identify four categories of traffic management policy which we will examine in turn:
- Forwarding policy
- Scheduling policy <...read more
by Alan | 8 September 2011
Posted 30 August 2011 | | 1 Comments
What's this virtualisation stuff all about? In the first of a series of blogs, I will be investigating what virtualisation is and why people are doing it. In subsequent parts, we will look at the how of it, the danger zones, and then get more specific.
Some history: Virtualisation was invented many moons ago by IBM. However, it came to the fore with the rise of client server computing and the x86 platform.
As companies started implementing multi-tiered applications, they found that each tier needed to be hosted on its own server. This led to ...read more
by Paul | 30 August 2011
Posted 7 August 2011 | | 0 Comments
In the beginning the Internet was designed to transmit packets on a best-effort basis. While the network makes a sincere attempt to transmit packets, there are no guarantees. The network does not allocate resources in advance to ensure reliable or timely delivery. As a result, packets may be delayed or even dropped. It is left to higher layer protocols (such as TCP) to ensure reliable data transfer.
Memory buffers are used to avoid collisions when two (or more) packets arrive at a communications link at the same time. A packet must wait until all the packets...read more
by Alan | 7 August 2011
Posted 21 June 2011 | | 0 Comments
This article discusses the regulation of wireless local area network (WLANs) operating in the 5 GHz spectrum range in the UK. This spectrum range is divided into three bands, namely A, B and C.
Bands A and B cover the spectrum range 5.150 to 5.725 GHz. Equipment must conform to ERC Decision 99(23) and IR 2006 in order to operate in these bands in the UK. Bands A and B have been granted licence-exempt status for public and private users.
Band C is a licensed band in the range 5.725 to 5.850 GHz. Band C is intended for fixed wireless access (FWA) services bet...read more
by Alan | 21 June 2011
Posted 31 May 2011 | | 0 Comments
A few weeks ago, I received an email from Meru Networks announcing an "End-of-Life Notification for Edge Switching", and a warning that my users had "announced the end of the wiring closet". Bold claims indeed. On closer inspection, it was an invitation to attend a webinar on Meru's Mobile Edge, the latest iteration of their 4th generation WLAN architecture. I was intrigued, sceptical and slightly concerned, as apart from Meru's product portfolio, IP Performanc...read more
by Pierre | 31 May 2011
Posted 12 May 2011 | | 1 Comments
Judging by recent press articles, Twitter posts and blogs, you'd be excused for thinking that the Interwebs is about to implode, the sky is falling, civilisation as we know it is about to collapse, and that we are about to be cast into a new Dark Age. Why? Because of IPv4 address exhaustion. You will also have read about IPv6 - the New Kid On The Block - and how we must all migrate to it, or risk being cast into a dystopian, post-apocalyptic world of ashen skies, seared earth and no Internet access. So what is this all about? Should you ca...read more
by Pierre | 12 May 2011