Developers Club geek daily blog

Stories from practice of optimization of a network

1 year, 5 months ago
Hi! I with colleagues optimize the available channels. We are constantly confused to optical sealants, to engineers-cablemen, in general, to loaders.



And our work is an analysis of a stack of protocols and its complete rearrangement under features of the channel, setup of the optimum sizes of a frame, collecting of several packets for the channel with big latency in one, a deduplication, normal compression, analysis of SSL and reassembly with the same certificate. It is solved in the simplest case installation of special iron on the accepting and transmitting end. As it is necessary to reach each point, we also work as exit engineers. And, as at any exit engineers, stories at us the sea. Below I will tell a little, I will only change a number of minor circumstances that it was impossible to recognize the customer.

For example, there are night works in very large shop. The administrator of the customer and our engineer came per hour nights into server, work. The engineer left in a toilet, returned. In a couple of minutes – knock at a door. Open — and at once GBR with automatic machines, at once legs for the body, a muzzle in a floor and in handcuffs flies.

Then approach police and main on shop. Main assesses a situation and with authority declares:
— I know this, this is our administrator. And I do not know this. Take away.

Read more »


Yota: achievements of the expiring year

1 year, 5 months ago


December — is a high time to sum up the results. Yota grows and develops. In 2015 we implemented many interesting projects. So, for example, distribution of our SIM cards for smartphones and tablets works already in 71 regions, communication of Yota in networks 2G/3G/4G works over all country. By the end of the 3rd quarter 2015 of our users there were one and a half million. Only from August till end of September the number of clients increased by 50%! Under a cat — there are more digits, dates and events, significant for us and our users.

Read more »


Get acquainted in more detail: multimedia gateway AudioCodes

1 year, 6 months ago
Good afternoon.

In this article we will begin session of several online lectures and articles on a separate line of the equipment AudioCodes – universal multimedia gateways which it is positioned for natural persons and small business. It is that segment which is called SOHO. We will provide the overview and information on a line of devices, history of its development and the short description of functionality in this article. It will be a question of universal CPE AudioCodes MediaPack of a series 26x (MP26x).

Read more »


Почему электронная почта не умрет никогда

1 year, 7 months ago


В последние пару лет в сети все чаще можно слышать дискуссии о том, что электронная почта, как инструмент коммуникации — пользователей между собой, и клиентов с компаниями — устарела и имеет целый ряд минусов. Такие материалы были, в том числе и на Хабре. В блоге Печкина мы много пишем об интересных техниках работы с email-рассылками, а сегодня представляем вашему вниманию адаптированный перевод материала из журнала The Atlantic, который призван объяснить, почему email — это лучшее, что до сих пор есть в интернете, и он не умрет никогда.

Read more »


The centralized notification Email

1 year, 7 months ago


Earlier we ignored notification Email per se. There are many services which allow to send notifications from the websites to their users to mail address, but there are no services where users could select where and how many to accept notifications.

Yes, we said that Email not abruptly and it can replace it with push-notifications.
But there is a huge layer of users who got used to receive notifications on mail. It distracts less, to someone it is simple more usual.
However e-mail has minuses, for example having entrusted e-mail box to the website — you endanger yourself receipts of spam, also letters from different services look on a miscellaneous that can confuse.

So why not to make the protected notifications in a format of small blocks from different services under control of the user? The user will be able to select the frequency of receipt of letters, will be able to unsubscribe at any time from this or that channel, further to configure a quiet time. Moreover — it will be possible to add several boxes and to select from what channels on what boxes to receive letters.

We already partially implemented it, is more detailed under a cat to whom to read laziness — it is possible to try in our service, having added mail in the section "Profile" in the Email Beta block.

Read more »


We take away an audio stream with Twilio on SIP and we send to RTMP CDN for further distribution

1 year, 7 months ago
image

It is known that in the nature there are CDN networks which are used for delivery of stream video to ultimate users. To take for example online broadcast of a football match. Historically it developed that the RTMP protocol developed by Adobe in certain time became very popular for Live-videokontent's delivery, and support of this protocol is in each Encoder-device respecting itself or the program which takes a video flow from the camera and sends to the server or CDN for the subsequent distribution. In article it is described how to make SIP a flow source for CDN.

Read more »


Protection of VoIP of networks

1 year, 7 months ago

I welcome all. To networks it is already quite a lot written articles that SBC protects VoIP a network and prevents theft of a traffic, reflects DoS/DDoS of attack and ensures full-fledged safety of VoIP of services. But it is very little written about what in reality there are attacks in the world of VoIP and SIP and what technologies ensure safety. In this article I tried to describe what there are attacks in the world of VoIP in what their feature what difference at them from normal network attacks and how AudioCodes SBC prevents these attacks and provides that protection about which all write.

Read more »


Cloudy explanations: we create operator service of virtual automatic telephone exchange in three days

1 year, 7 months ago
Just several years ago searchers in response to search query of "Cloud" submitted a great number of references to children's animated films and articles in Wikipedia about the atmospheric phenomena. In the last two-three years the tendency changed and publications with the description of cloud computing and platforms began to get to a top of issue, and the term "Clouds" causes ambiguous associations in IT specialists now: already not everyone imagines "the products of condensation of water vapor weighed in the atmosphere", rather in consciousness of "the correct IT specialist" there are images of virtual platforms and platforms, different IaaS, PaaS, SaaS. Virtualization of everyone and everything — one of the main trends of decade, a set of client services moved in clouds long ago, large telecom businesses implement all new and new VAS in addition to the main services, and often, the fact that once there was Value Added Service turns into a basic product. Communication services in this sense are not an exception and the Cloudy Automatic Telephone Exchange service becomes just obligatory point in the list of sentences of the telephone operator. We will tell about how (including with our help) quickly and rather easy to start own service of cloudy automatic telephone exchange below.


Read more »


The counterfeit base station for $1400 allows to define precisely location of phone in 4G/LTE of a network

1 year, 7 months ago


Researchers developed an inexpensive method of detection of exact location of the smartphone working in LTE/4G of a cellular network. This development lets know that mobile networks of new generations are also vulnerable to some types of attacks, as well as the networks working on former, already outdated, to standards of communication and specifications.

New attack uses vulnerability in the LTE protocol. This standard will provide by the end of the year communication for 1,37 billion subscribers. For carrying out attack it is required to bring together system from elements which total cost makes about $1400. As software Open Source software is used. The system, the NodeB node, allows to define location of phones compatible to the LTE standard, with an accuracy of 10-20 meters. In certain cases this equipment allows to learn also GPS coordinates of devices though attack of this kind can be found by the user of the smartphone. Also one more method of determination of coordinates of smartphones is developed, at the same time attack cannot almost be found. This method allows to define location of the set device within couple of square kilometers.

Read more »


As we did HD Wi-Fi at stadium on 33 thousand people in the Krasnodar region in what features of a dense covering, and why Wi-Fi to the fan specifically consist

1 year, 8 months ago
Can seem that Wi-Fi at stadium is not necessary in general. Came to be ill – so look behind game, but do not post a selfie and read mail. But is not present, Wi-Fi is necessary for two important reasons. First, at such accumulation of people channels of a cellular network will be extremely quickly disassembled, and the most part of fans will remain for a while without phone. Secondly, actually, owners of stadium very much wanted to give special mobile application for all fans.

Inside – schemes of arrangement of players in the field, statistics on a match and players, plus strimingovy video from cameras that it was possible to see close up in persons on the tablet or phone what occurs. Well and at once repetitions of important points from different foreshortenings.


On radio inspection


Result of inspection of a membrane

For all this fast Wi-Fi of high density and with the minimum interferentsionalny phenomena is necessary. Here not to stick normal hotspot – good examination of radio inspection, plus the special equipment is necessary. Result – 150 cunning access points with beamforming after enough nontrivial works.

Read more »