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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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YANG - Data Modelling Language used in Networking

YANG stands for Yet Another Next Generation. It is a data modeling language. It is used for describing Network topologies. Also, it models the configuration and state data manipulated by the NETCONF and Network Configuration Protocol. Both these YANG and NETCONF are tools used for automating configuration tasks for various devices present in a Software Defined Network.

YANG can describe nodes present in the network and interactions between them. It can define a hierarchy of data used for NETCONF operations like State data, Remote Procedure Call (RPC), and configuration. It was developed by IETF (Internet Engineering Task Force) and models written in YANG are readable by humans.

In YANG, data structures are represented in an XML tree format. As YANG is a protocol independent, it can be converted into XML or JSON encoding format based on the usage of Network configuration protocol.

Advantages of YANG:
YANG has the following advantages:
  • It can model both the configuration and state of layers of the network
  • Automated operation and policies are possible through YANG
  • YANG can be integrated easily with Operation Support Systems and Software Defined Network Controller
  • Supports network management applications and interoperability to model management data 
  • YANG models are easy to learn and read by humans
  • Supports the modularity of data through modules and submodules
  • Support the use of constraints for configuration validation
YANG in practical use:
Let us discuss some of the practical applications where YANG is being used.
  • Open Day Light an SDN controller uses YANG for Model Driver Service Abstraction Layer
  • Tail-f uses YANG as a data modeling language for its Network Control System
  • Metaswitch company also uses the YANG modeling language for controlling its Control Plane products
Conclusion:
YANG a data modeling language strength is configuring network devices. It can be used to define interfaces between Virtualized Network Functions (VNF’s). To describe end-to-end services using the cloud, one can use TOSCA (Topology and Orchestration Specification for Cloud Applications) for orchestration and YANG for describing the services.

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