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The importance of network maintenance and fault-finding

March 20th, 2024

Network engineer test equipment

 

Most people on the planet now use some form of communications network as part of their daily lives. We are so accustomed having our phones, computers and many other devices connected to the outside world, when something goes wrong with the network, it can cause a lot of disruption.

When communications networks go wrong, it often creates international news, such as when the telecoms network run by Australian firm Optus went down for almost 12 hours in November 2023. Such outages are rare, but in a connected world, being unable to place phone calls, use the internet, make card payments, use public transport or call the emergency services can be almost disastrous.

Which is why regular network maintenance and fault-finding is an essential task for telecommunications and network engineers. Skilled engineers are able to constantly be aware of potential issues before they arise, work on preventative maintenance and swiftly identify faults and rectify them as they occur.

PTT has two updated online courses covering this topic that are essential for those responsible for the installation and maintenance of telecommunications, local and wide area networks.

The “Telecoms testing and fault finding” course describes how to follow a structured approach to fault finding and maintenance, and the role and significance of the various tests employed on telecommunications networks and broadband connections.

Network testing and fault-finding” also explains the benefits and methods of following a structured approach to fault-finding and maintenance, and describes the role of the various tests employed on Ethernet/IP networks and their use in fault finding and measuring network performance.

These online courses can either be studied as a standalone course of study by anybody working in the industry or can become part of a structured programme such as an apprenticeship. In the UK, these courses can fulfil certain knowledge objectives in a number of digital apprenticeships, including:
Level 2 Telecoms Field Operative (K9, K10)
Level 3 Information Communications Technician – Network Technician (K3, K9, K25, K28)
Level 3 Information Communications Technician – Digital Communications Technician (K3, K9, K43)
Level 4 Network Engineer (K1, K4, K5, K6, K15, K17)

If you want to discuss this subject with us further, or any training needs, please contact us.

 

Diverted down the wrong road

February 19th, 2024

IP routing

We take it for granted that when we click on a link to visit a web page, we will be directed to the intended web site. But ensuring traffic reaches its intended destination depends on interactions between computers and networks around the world that are operated by many different organisations. And the routing process depends on trust. When network A tells network B that it can provide a route to destination C, network B assumes network A is run by good guys and believes them.

Routes are advertised using border gateway protocol (BGP) messages. In the early days of the Internet, it was a reasonable assumption that those BGP messages could be trusted. But as the Internet has grown, that is no longer the case. Those with bad intent may hijack the BGP system to divert traffic to their servers to harvest information or money. Hijacking BGP routing is analogous to an adversary changing road signs, redirecting traffic under the pretence of leading them to their intended destination.

A BGP weakness was exploited in 2018 to divert traffic destined for a cryptocurrency website to the hijackers’ phishing site on a server in Russia. During the attack, which lasted for two hours, the hijackers stole $150,000 in cryptocurrency. Although the cryptocurrency site relied on Amazon Web Services (AWS), the hijacking was possible without having to attack the AWS or cryptocurrency servers. Instead, the hacker advertised a supposedly more attractive route to the cryptocurrency site to an Ohio-based internet service provider who took the advert on trust and passed it on to others.

Apart from the activities of those with bad intent, human error can also cause significant disruption. In 2021, it was reported that a Vodafone India network mistakenly advertised that it provided routes to thousands of addresses, when it didn’t, causing the internet to flood this network with traffic that was not meant to go through it. This had a major impact on service providers around the world including Google.

There have been many more examples of the disruption caused by incorrect routing in recent years. Various measures to combat the vulnerability of BGP are now available but not all network operators have adopted them.

PTT’s new online course “Exterior IP routing” describes the role and operation of BGP and the security measures that can be taken to protect the global routing system. Its sister course “Interior IP routing” is also available.

 

Light speed satellite communications

January 4th, 2024

Conventional low earth orbit (LEO) satellite communications over long distances may involve multiple hops between satellites and ground-based antennae with a subsequent increase in latency. Providing direct communications between LEO satellites using lasers allows a communications session to be forwarded between satellites minimising the number of satellite to ground station links involved in the session.

The Amazon LEO initiative Project Kuiper has recently completed a test of an optical inter-satellite link (OISL) operating at 100 Gbit/s over a distance of over 600 km. Project Kuiper has the aim of providing a mesh of inter-satellite links providing global low latency communications.

Reducing the number of hops reduces propagation distances with a subsequent reduction in delay. Since optical signals travel faster in space than through glass fibre, the latency of the OISL system should be lower than that of an equivalent terrestrial optical fibre system.

But terrestrial optical links offer even faster transmission speeds. Cienna has recently rolled out a nation-wide optical fibre network in South Korea spanning 1,000 km and capable of transmitting at 600 Gbit/s per wavelength.
The Cienna system achieves these high speeds using coherent detection. Optical add-drop multiplexers allow individual wavelengths to be switched to serve different locations.

PTT offers online courses introducing LEO satellite communications and optical coherent detection.