Chapter 1.1: What is the Internet?
Requests for Comments (RFC)
The standards documents of the IETF
TCP/IP
Transmission Control Protocol (TCP) and Internet Protocol. These are the protocols that control the sending and receiving of information within the internet.
communication links and packet switches
a network that connects ends systems.
host/end system
all devices hooked up to the internet. The internets end systems include desktop computers, servers, and mobile devices. Also referred to as hosts because they host (run) application programs such as a web browser program, a web server program, an e-mail client program, or an e-mail server program. Divided into clients and servers.
distributed applications
applications that involve multiple end systems that exchange data with each other.
protocol
defines the format and the order of messages exchanged between two or more communicating entities, as well as the actions taken on the transmission and/or receipt of a message or other event.
Internet Standards
developed by the internet engineering task force (IETF)
Internet Service Providers (ISPs)
end systems access the internet through ISPs each ISP is a network of packet switches and communication links. Provide different types of network access such as residential broadband access, high-speed local area network access, and mobile wireless access. Also provide internet access to content providers.
transmission rate of a link
measured in bits/second
internet socket interface
specifies how a program running on one end system asks the internet infrastructure to deliver data to a specific destination program running on another end system. This is a set of rules that the sending program must follow so that the internet can deliver the data to the destination program.
packet-switched network
takes a packet arriving on one of its incoming communication links and forwards that packet on one of its outgoing communication links. The most prominent types are routers and link-layer switches.
route/path
the path through the network that a packet takes through communication links and packet switches from the sending end system to the receiving end system.
When are link-layer switches generally used?
typically used in access networks
When are routers generally used?
typically used in the network core.
packets
when an end system has data to send to another end system, the sending end system segments the data and adds header bytes to each segment, creating packets which are then sent through the network to the destination end system, where they are reassembled into the original data.
