Lesson 4.3: The Architecture of the Internet Flashcards
The Three Tiers of ISPs
Tier 1, at the top of the ISP hierarchy, is the least common type of ISP and serves as the backbone of the internet. Tier 1 ISPs consist of high-speed, high-capacity, international WANs that are typically operated by large communication companies.
Tier 2 ISPs are more common and regional in scope. Tier 1 and Tier 2 ISPs are essentially networks of routers that collectively provide the internet’s communication infrastructure.
Tier 3 ISPs (access ISPs) are typically independent internets, sometimes called intranets, operated by a single organization that supplies internet access to homes and businesses. The devices used to connect to the access ISP are called end systems or hosts. These include common internet devices such as PCs, laptops, and smartphones, but also devices such as cameras, automobiles, and home appliances. A variety of technologies are used to connect end systems to larger networks. Common connecting technologies are telephone lines, cables, and satellites.
ICANN (Internet Corporation for Assigned Names and Numbers)
The ICANN (Internet Corporation for Assigned Names and Numbers), a nonprofit organization that coordinates the internet’s operations, awards blocks of consecutively numbered IP addresses to ISPs. ISPs then assign a unique IP address to each machine within their region of authority.
Network protocols
l. Network protocols are rules, procedures, and formats that govern the communication of multiple devices over a network.
Simple Mail Transfer Protocol (SMTP)
SMTP uses Domain Name System (DNS) lookups to identify the recipient of the email and send the message over the internet to a mail server where it can be retrieved using protocols such as POP3 (Post Office Protocol version 3) and IMAP (Internet Message Access Protocol).
VoIP (Voice over Internet Protocol)
VoIP (Voice over Internet Protocol) is used for voice communication over the Internet. VoIP operates by establishing a connection between two devices and then performing real-time, two-way transmission of audio data. Softphones allow two or more computers to share a call without any additional hardware. Analog telephone adapters allow users to connect their physical phones to a port that digitizes and then transmits real-time audio data.
content delivery networks (CDNs)
which are groups of servers distributed strategically over the internet that stream copies of content to nearby end users. A networking technology called anycast enables an end user to connect to the closest server automatically.
extensible markup language (XML)
the extensible markup language (XML), provides a standardized style for designing notational systems for representing data as text files. XML emphasizes semantics, while HTML focuses on appearance.
