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Commands used in Dockefile - Part4

  Docker is an opensource tool used for virtualization and deliver software in the form of packages called Containers. It is one of the most important tools used in networking domain.  Dockerfile  is a template for building the image which contains commands needed to package the software. In this post, I am going to explain the commands ADD & COPY used in  Dockerfile .   ADD Command:   ADD command is used to copy files, directories or files from remote URLS to destination path in the image. The source paths can contain wildcards.   If the destination has relative path, it is relative to the Working directory of the image. Note that source path is always relative to the Docker build context.   ADD command will not support authentication. So, if there are any protected files to be added in  Dockerfile  building, use other tools like curl or  wget   Dockerfile  copying Single & Multiple files, directory using ADD inst...
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Introduction to GSM

What is GSM? 
GSM stands for Global System for Mobile Communication. It is nothing but a digital mobile network used by mobiles in Europe and some other countries. GSM uses a variant of Time Division Multiple Access (TDMA). It digitizes and compresses data and send it via the channel in their own time slots. GSM operates at the frequency of 900 or 1800MHz. 

Composition of GSM Network: 
GSM network is composed of three parts namely the Network Switching Subsystem (NSS), Operation and Support Subsystem (OSS), and Base Station Subsystem (BSS). The architecture of the GSM network looks like below: 
GSM architecture 
In GSM, a mobile device is connected to the network via hardware of the BSS. The SIM (Subscriber Identity Module) card is used for the authentication of the mobile user.   

The traffic between NSS and mobile devices is controlled by BSS. The BSS has two components namely Base Transceiver Station (BTS) and Base Station Controller (BSC). BTS has the equipment necessary to communicate with mobile phones. BSC is another entity that communicates with BTS and controls a group of BTS components. 

The NSS component is also known as the core network is used to track the location of callers to enable delivery of the cellular services. Mobile carriers have their own NSS. The NSS has various parts like Mobile Switching Center (MSC) and Home Location Register (HLN). These components perform functions like routing calls, SMS (Short Message Service) and storing caller account information. 

Security of GSM: 
GSM uses authentication in the form of a password. The password is encrypted using stream cipher cryptography algorithms like A5/1, A5/2, and A5/3. These are broken and hence GSM is susceptible to plain text attacks.   

GSM uses General Packet Radio Service (GPRS) to transmit data via web browsing. GPRS uses algorithms like GEA/1, GEA/2 and these algorithms are also broken. 

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