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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 EPC Network and its architecture

What is EPC? 
EPC stands for Evolved Packet Core. It is a framework to provide both voice and data on a 4G LTE (Long Term Evolution) network. 

2G and 3G networks process voice using circuit switched domain and data using the packet-switched domain. But the EPC network unifies both data as well as voice on Internet Protocol (IP) Server architecture and treat it as an IP application. 

Key Components of EPC: 
The following components play a vital role in the EPC network: 
  • Mobile Management Entity: It takes care of session management, authentication of user and tracking of the user across the network 

  • Serving Gateway (S-Gateway): It is responsible for the routing of data packets across access networks 

  • Packet Data Node Gateway (PGW): It is an interface between the LTE network and other packet data networks. It also helps in maintaining Quality of Service (QoS) and deep inspection of the packet 

  • Policy and Charging Rules Function: It is another key entity to detect data flow, enforce the policy and charge based on the flow 

The standards of the EPC network were specified by the industry trade group Third Generation Partnership Project (3GPP) in early 2009. This EPC network was used as the core component of Service Architecture Evolution (SAE) and also 3GPP LTE architecture. 

Difference between GSM, GPRS/UMTS, and EPC: 
In GSM, all the services of mobile like data, voice, and SMS are done using a circuit switching network. That is, first circuit/path is established between the caller and calling party and services happen over that path. 

In GPRS, both the circuit switched and packet switched networks are used. Data is sent using packet switched networks whereas voice and SMS are sent using the circuit switched network. This improves the flexibility and efficiency of the network. 

In EPC, there is no more concept of circuit switched networks. And hence EPC is known as the evolution of the packet switched architecture in GPRS/UMTS. Also, EPC uses the IP protocol to transfer all the services. 

Architecture of the EPC Network: 
3GPP released the architecture of EPC in release 8 of the standard 
The architecture proposed by the 3GPP is the flat architecture to handle the payload in an efficient manner using less cost. To handle traffic, only a few nodes are used and this helps in avoiding protocol conversion. 

To scale the network, 3GPP decided to separate the control plane from the data plane. This helps network operators to adapt their network in an easy manner. 
The basic architecture of the EPC network looks like below: 
 
Here User Equipment (UE) a simple mobile device is connected to EPC via Evolved Universal Terrestrial Radio Access Network(E-UTRAN) I.e. LTE Access network.  eNodeB acts as a base station for the LTE access network. EPC consists of 4 elements namely Serving Gateway (S-GW), Packet Data Node Gateway (PDN GW), Mobile Management Entity (MME), and Home Subscriber Server (HSS). 

HSS: 
HSS stands for Home Subscriber Server. HSS is a database containing user and subscriber related information. Its main purpose is to support functions in mobility management like call & session setup, user authentication, and authorization. 

Serving Gateway: 
S-GW deals with the user plane and manages traffic between UE and external networks. It is the interconnection between eNodeB and EPC.  This serves UE by routing incoming and outgoing IP packets. This is logically connected to PDN GW. Also, it is an anchor point for intra LTE mobility. 

PDN GW: 
This is the interconnection between LTE and external IP networks. It routes packets from and to the PDN. PDN GW performs functions like IP prefix allocation, IP address allocation, and policy control & charging. 
SDN and PDN GW can be combinedly implemented by some vendors 

MME: 
MME deals with the control plane and performs functions like signaling related to mobility and security for E-UTRAN access. It also performs the tracking and paging of UE in idle mode.  

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