Distributed Networks Distributed Networks




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Lesson 2Prerequisites
Objective Verify that you have the right background for this course.
  1. Windows 2008 or 2012 knowledge and experience
  2. A thorough understanding of DHCP, WINS, and Internet Protocol (IP) subnetting and routing
  3. Experience supporting networks and end users
Most of the terms found on this website can be found on the web.

This course is intended for Active Directory Technology Specialists, Server and Enterprise Administrators who want to learn how to implement Active Directory Domain Services in Windows Server environments. Those participating in this course would be interested in learning how to secure domains by using Group Policies, restore, monitor, and troubleshoot configuration to ensure trouble-free operation of Active Directory Domain Services.
In the next lesson, you will learn what you need to take this course.


History of Relays and Networks

Some would argue that the X.25 networks, the first cloud services in widespread use, were popular in the 1970s and 1980s for remote mainframe terminal access are the beginnings of the Enterprise WAN.
Previsouly, if you wanted to connect LANs that were not in the same location, you used point-to-point leased lines.
These were typically DS0 (56 Kilo bits per second) connections, and then the more expensive T1/E1 connections, and because they were expensive, fractional T1 or T3 become available. The connections were first done using remote bridges at each end, and later with devices called routers, popularized by Cisco.
At the beginning of the 1990s, Frame Relay service was introduced. While using the same DS0 and fractional or full T1/E1 and T3/E3 connections, by connecting to a cloud from a service provider, you no longer needed to purchase and manage individual links between each of the locations that you wanted to connect. Frame Relay service offered much lower monthly WAN costs, far fewer physical connections to manage, allowed the expensive last-mile link bandwidth to be shared (and thus used more efficiently) across multiple remote connections, and required less expensive router hardware than the point-to-point alternative. This story of OpEx and CapEx caused a revolution in the corporate WAN and contributed to its rapid growth. Within 5 years of its introduction, even the most conservative enterprises such as banks had migrated to Frame Relay. It was the fastest uptake of any WAN service in history including the Internet.

Elements of Point-to-Point Leased Lines

A point-to-point leased line is the most reliable solution for the communication and connectivity that modern businesses require. Leased, since the service is paid for with a fixed fee for an agreed upon duration and service capacity. The fixed points in a private network are connected through dedicated digital circuits that vary in capacity and speeds. This allows businesses to extend the coverage of the business wide area network using secured, highly-reliable and high-speed network connections.