Lessons In This Course
In the first lesson, we’ll identify the purpose of this course as being an introduction to all of the different aspects of broadband converged IP telecom: the concepts of convergence and broadband, network components and structure, key protocols, copper, fiber and wireless access; residential, business and wholesale services, all the different types of network equipment, and how and where carriers interconnect.
Lesson 2 begins the course proper defining convergence or service integration, where all services: voice, video and data are carried together on the same access circuits and same network. We’ll see there are two possibilities for convergence: carry everything in channels like voice; or carry everything in packets like data; and after previous failed attempts: ISDN (channels) and ATM (packets), the third time is the charm with everything in IP packets, plus a packet traffic management technology called MPLS.
Lesson 3 defines the term “broadband”. We’ll understand what bandwidth is, in both the analog and digital worlds; or more precisely: in the frequency channel and digital worlds. We’ll discuss how much “broad” might be from a regulatory perspective, and from a user requirements perspective; and how broadband access to the Internet will become a right, just as electricity and telephone before it.
Lesson 4 introduces a graphical model identifying the all of the different aspects of broadband converged IP telecommunications, which are covered in detail in subsequent lessons and courses. We’ll understand the parts of the physical network: core, edge and access, and enumerate services grouped by residential, business and wholesale, and see how data centers fit into the picture.
Lesson 5 is a closer look at the heart of the model: the network core. The core implements high-capacity, high-availability communications using Optical Ethernet point-to-point links between major switching or aggregation points on a carrier’s network. We’ll see all the different buildings these could be, how high availability requires redundant connections, how ring patterns are the cheapest way to implement it, and the technologies used for cut line protection switching.
Lesson 6 introduces fundamental networking concepts, viewing networks as point-to-point links terminated on routers in different locations. We’ll examine the most popular technology for links, Optical Ethernet, which moves bits grouped into MAC frames point-to-point over fiber. You’ll learn how IP packets are carried in MAC frames to a router, which uses the destination IP address to make a route decision, then forwards the IP packet in a MAC frame to the next router. We’ll see how MPLS is used instead of IP in the core of big networks, allowing control of the routing of flows of packets by a Network Operations Center.
Lesson 7 is dedicated to network access technologies, called the “last mile”, the physical connection between the user and the network; the face of the telecom network to users. To get started, we group access technologies by physical medium: copper, fiber and wireless. Copper includes twisted pair loops, LAN cables and old-fashioned T1s, as well as coaxial cable CATV infrastructure. Fiber means Optical Ethernet, shared links for residences via Passive Optical Networks and dedicated links for businesses. Wireless includes 4G LTE and 5G, used for both fixed and mobile applications, and satellites.
In Lesson 8, we’ll define a service provided by a telecommunication service provider as being made of three components: access circuit, network connection type and billing agreement. We’ll first understand why people draw networks as clouds in high-level diagrams, to establish the idea of a service versus a circuit. Then we’ll explore how access circuits, network connections and billing agreements combine to make a service.
Lesson 9 is a lengthy introduction to the most popular services sold by service providers, organized into residential, business and wholesale. We’ll cover broadband residential Internet, and telephone service, television and video on demand delivered as Internet traffic or delivered direct by your ISP; and the term VPN, which can mean at least four different things. We’ll introduce business services, including MPLS VPNs, SD-WANs, Centrex and SIP Trunking to replace PBX trunks; and wholesale services: dark fiber; wavelengths on a fiber; services that moves MAC frames, called a Virtual Private LAN Service (VPLS) or Carrier Ethernet, IP packet communications, Internet transit and peering.
Lesson 10 is also a longer lesson, surveying the main types of network equipment in use today, beginning with Layer 2 Switches and Routers, the building blocks of the broadband converged IP network. Then we’ll cover Frequency-Division Multiplexers, used in radio and coax, and fiber systems where they are called Wave-Division Multiplexers, plus fiber cross-connects and wavelength add-drop multiplexers. You’ll learn the basics of Time-Division Multiplexers and DS0 channels, and gateways that convert media between IP packets and DS0 channels, and signaling between SIP and ISDN messages.
Lesson 11, the final lesson in this course, covers the two and a half ways that carriers connect to allow communications. First telephone calls to and from PSTN telephone numbers, connecting LECs and IXCs with tandem access trunks at toll center buildings, which is highly regulated and specified in minute detail in tariffs. Second, ISPs exchanging IP packets at Internet Exchange buildings, which is barely regulated if at all. The half is connections for MPLS VPNs across different carriers when they are partnering to provide global communications.
Graphical model identifying different aspects of broadband converged IP telecommunications
