Whispers & Screams
And Other Things
Vastly experienced, versatile senior technical asset with a broad range of highly evolved skills from team building to high-level technology solution implementations. A courageous and tenacious leader with proven experience in business development, organisational visioning, cutting edge information technology deployments, and as a senior management liaison. Experienced at working at all levels from Start-up to Corporate, I thrive on change and take the lead to engage and drive the engineering landscape in any business An outgoing personality, with high energy levels who is customer focused but understands the need for a structured approach to business. A mature and collaborative style provides excellent communication and presentation skills and, drawing on past experience, gives the credibility to build trust. A strategic thinker, who is innovative and creative and makes technically 'savvy' decisions and encourages others to do so, whilst totally focused on success and how this drives results.

Best definition of the labour party I ever saw..


Ineptocracy (in-ep-toc’-ra-cy) - a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.
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Coming back to life

Where were you when I was burned and broken
While the days slipped by from my window watching
And where were you when I was hurt and I was helpless
Because the things you say and the things you do surround me
While you were hanging yourself on someone else's words
Dying to believe in what you heard
I was staring straight into the shining sun

Lost in thought and lost in time
While the seeds of life and the seeds of change were planted
Outside the rain fell dark and slow
While I pondered on this dangerous but irresistible pastime

I took a heavenly ride through our silence
I knew the moment had arrived
For killing the past and coming back to life

I took a heavenly ride through our silence
I knew the waiting had begun
And I headed straight..into the shining sun.
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From childhood’s hour I have not been
As others were—I have not seen
As others saw—I could not bring
My passions from a common spring—
From the same source I have not taken
My sorrow—I could not awaken
My heart to joy at the same tone—
And all I lov’d—I lov’d alone—
Then—in my childhood—in the dawn
Of a most stormy life—was drawn
From ev’ry depth of good and ill
The mystery which binds me still—
From the torrent, or the fountain—
From the red cliff of the mountain—
From the sun that ’round me roll’d
In its autumn tint of gold—
From the lightning in the sky
As it pass’d me flying by—
From the thunder, and the storm—
And the cloud that took the form
(When the rest of Heaven was blue)
Of a demon in my view—
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The EIGRP (Enhanced Interior Gateway Routing Protocol) metric

EIGRP (Enhanced Interior Gateway Routing Protocol) is a network protocol that lets routers exchange information more efficiently than was the case with older routing protocols. EIGRP which is a proprietary protocol evolved from IGRP (Interior Gateway Routing Protocol) and routers using either EIGRP and IGRP can interoperate because the metric (criteria used for selecting a route) used with one protocol can be translated into the metrics of the other protocol. It is this metric which we will examine in more detail.

Using EIGRP, a router keeps a copy of its neighbour’s routing tables. If it can’t find a route to a destination in one of these tables, it queries its neighbours for a route and they in turn query their neighbours until a route is found. When a routing table entry changes in one of the routers, it notifies its neighbours of the change. To keep all routers aware of the state of neighbours, each router sends out a periodic “hello” packet. A router from which no “hello” packet has been received in a certain period of time is assumed to be inoperative.

EIGRP uses the Diffusing-Update Algorithm (DUAL) to determine the most efficient (least cost) route to a destination. A DUAL finite state machine contains decision information used by the algorithm to determine the least-cost route (which considers distance and whether a destination path is loop-free).

Figure 1

The Diffusing Update Algorithm (DUAL) is a modification of the way distance-vector routing typically works that allows the router to identify loop free failover paths.  This concept is easier to grasp if you imagine it geographically. Consider the map of the UK midlands shown in Figure1. The numbers show approximate travel distance, in miles. Imagine that you live in Glasgow. From Glasgow, you need to determine the best path to Hull. Imagine that each of Glasgow’s neighbours advertises a path to Hull. Each neighbour advertises its cost (travel distance) to get to Hull. The cost from the neighbour to the destination is called the advertised distance. The cost from Glasgow itself is called the feasible distance.
In this example, Newcastle reports that if Glasgow routed to Hull through Newcastle, the total cost (feasible distance) is 302 miles, and that the remaining cost once the traffic gets to Newcastle is only 141 miles. Table1 shows distances reported from Glasgow to Hull going through each of Glasgow’s neighbours.

Table 1

Glasgow will select the route with the lowest feasible distance which is the path through Newcastle.

If the Glasgow-Newcastle road were to be closed, Glasgow knows it may fail over to Carlisle without creating a loop. Notice that the distance from Carlisle to Hull (211 miles) is less than the distance from Glasgow to Hull (302 miles). Because Carlisle is closer to Hull, routing through Hull does not involve driving to Carlisle and then driving back to Glasgow (as it would for Ayr). Carlisle is a guaranteed loop free path.

The idea that a path through a neighbour is loop free if the neighbour is closer is called the feasibility requirement and can be restated as "using a path where the neighbour's advertised distance is less than our feasible distance will not result in a loop."

The neighbour with the best path is referred to as the successor. Neighbours that meet the feasibility requirement are called feasible successors. In emergencies, EIGRP understands that using feasible successors will not cause a routing loop and instantly switches to the backup paths.

Notice that Ayr is not a feasible successor. Ayr's AD (337) is higher than Newcastle's FD (302). For all we know, driving to Hull through Ayr involves driving from Glasgow to Ayr, then turning around and driving back to Glasgow before continuing on to Hull (in fact, it does). Ayr will still be queried if the best path is lost and no feasible successors are available because potentially there could be a path that way; however, paths that do not
meet the feasibility requirement will not be inserted into the routing table without careful consideration.

EIGRP uses a sophisticated metric that considers bandwidth, load, reliability and delay. That metric is:

[latex]256, *, left(K_1, *, bandwidth ,+, dfrac {K_2 ,*, bandwidth}{256 - load}, +, K_3 ,*, delayright), *,dfrac {K_5}{reliability ,+, K_4}[/latex]

Although this equation looks intimidating, a little work will help you understand the maths and the impact the metric has on route selection.

You first need to understand that EIGRP selects path based on the fastest path. To do that it uses K-values to balance bandwidth and delay. The K-values are constants that are used to adjust the relative contribution of the various parameters to the total metric. In other words, if you wanted delay to be much more relatively important than bandwidth, you might set K3 to a much larger number.

You next need to understand the variables:

    • Bandwidth—Bandwidth is defined as (100 000 000 / slowest link in the path) kbps. Because routing protocols select the lowest metric, inverting the bandwidth (using it as the divisor) makes faster paths have lower costs.


    • Load and reliability—Load and reliability are 8-bit calculated values based on the performance of the link. Both are multiplied by a zero K-value, so neither is used.


    • Delay—Delay is a constant value on every interface type, and is stored in terms of microseconds. For example, serial links have a delay of 20,000 microseconds and Ethernet lines have a delay of 1000 microseconds. EIGRP uses the sum of all delays along the path, in tens of microseconds.

By default, K1=K3=1 and K2=K4=K5=0. Those who followed the maths will note that when K5=0 the metric is always zero. Because this is not useful, EIGRP simply ignores everything outside the parentheses. Therefore, given the default K-values the equation becomes:

[latex]256, *, left(1, *, bandwidth ,+, dfrac {0 ,*, bandwidth}{256 - load}, +, 1 ,*, delayright), *,dfrac {0}{reliability ,+, 0}[/latex]

Substituting the earlier description of variables, the equation becomes 100,000,000 divided by the chokepoint bandwidth plus the sum of the delays:

[latex]256, *, left(dfrac {10^7}{min(bandwidth)}, +,sum,dfrac {delays}{10}right)[/latex]

As a final note, it is important to remember that routers running EIGRP will not become neighbours unless they share K-values. That said however you really should not change the K-values from the default without a compelling reason.

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What is a Yagi Antenna?

Ask your average person what a Yagi antenna is and they will probably look at you with a puzzled expression. The fact is however that everybody in the UK has probably seen a Yagi antenna and in all likelihood used one at some point.

The ubiquitous TV antenna.
Example of a Yagi TV aerial.

The Yagi antenna was invented by two Japanese researchers in 1926, namely Hidetsugu Yagi and Shintaro Uda.
It is more correctly called the Yagi-Uda antenna however Mr Uda seems to have slipped off the credits somewhat.
It is an example of a subtype of antenna known as the "beam antenna" but having established that its on almost every roof in the UK, why does it interest us at Rustyice Solutions?

In recent years, telecommunications has gone through a revolution with mobile communications becoming the greatest driving force behind this. Whether you like it or not all mobile communication and by definition all radio communication requires an antenna for reception and transmission of the signal. This antenna has largely become hidden from the view of the consumer with form and function of equipments dictating that an antenna can not be visible from the outside in most equipments but they are still there and play a fundamental part in everything that we do in the mobile communications world. So what does the ugly old rooftop TV antenna have to do with todays sleek 21st century devices you may ask?

'Quite a lot' is the answer. First, lets look at the technicals of the Yagi antenna itself.

Yagi with folded dipole driven element.

The Yagi antenna is usually made up of a single driven (dipole) elelment and a reflector along with a number of parasitic elements whose size and spacing is determined by the frequencies which one wishes to receive or transmit. The size of the dipole is usually half of the wavelength (?) of the centre frequency or, if a folded dipole is used, the total length of the conductor is equal to almost 1 x ?. It is directional along the axis perpendicular to the dipole in the plane of the elements, from the reflector toward the driven (dipole) element and the parasitic elements which are also known as directors. Typical spacings between elements vary from about 1/10 to 1/4 of a wavelength, depending on the specific design and performance requirements. The lengths of the directors are smaller than that of the driven element, which is smaller than that of the reflector(s) according to an elaborate design procedure. These elements are usually parallel in one plane, supported on a single crossbar known as a boom.

Laptop USB Yagi antenna

Many of the higher end wireless networking manufacturers use emulated yagi antennas in their products today however we are sure you will agree that the coolest gizmo to get yourself a wifi signal where everybody else just simply can and will not be able to connect is this example of antenna technology at its finest over there on the left. In all, we believe, a perfect example of how technology might surge ahead at great speed every day but there really is no escape from good old fashioned antenna theory when you want to get yourself connected on the move.

At Rustyice Solutions, we have many shared years of experience in the field of HF, VHF, UHF and even SHF radio communications. If you or your business needs help getting connected on the fringes of reasonable reception via off the shelf products why not give us a call. We are sure we will be able to bring our considerable experience to bear in getting you connected. Of course you could always go for the item below which, it is said can connect to a wifi network at a range of 10 miles but youre as likely to get the jail as get connected so maybe you should just leave it to us.

The (Day of the Jackal) YAGI sniper rifle

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