ch.1

end systems (hosts)

Laptops, smartphones, tablets, TVs, gaming consoles, Web cams, automobiles, environmental sensing devices, picture frames, and home electrical and security systems are all devices that fall under the category of what?

communication links and packet switches

End systems are connected together by a network of _____________ _____ and ______ ________.

transmission rate

The speed of a link measured in bits/second. (R)

packets

packages of information

routers and link-layer switches

The two most prominent types of packet switches

route (path)

The sequence of communication links and packet switches traversed by a packet from the sending end system to the receiving end system

Internet Service Provider

ISP the abbreviation for?

cable, DSL, high-speed lan, wifi, 56k dial up.

Types of ISPs

TCP and IP (TCP/IP)

Two of the most important protocols in the internet (not UDP)

IETF and RFCs

Two common internet standards

Request for comments

RFC is the abbreviation for

Internet Engineering Task Force

IETF is the abbreviation for

Distributed applications

Multiple end systems that exchange data with each other

Application Programming Interface (API)

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

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.

Network edge

What part of the internet are end systems found?

clients

One of the two categories that hosts are divided into; PCs, smartphones, and other mobile devices

servers

One of the two categories that hosts are divided into; powerful machines that store and distribute Web pages, stream video, relay e-mail...

access networks

The network that physically connects an end system to the first router (also known as the "edge router")

digital subscriber line

DSL is the abbreviation for?

hybrid fiber coax (HFC)

Both fiber and coaxial cable are employed in this system, it is often referred to as

fiber to the home (FTTH)

An up-and-coming technology that promises even higher speeds than DSL which provides a direct fiber optic connection to homes. (Verizon's FIOS)

central office

the abbreviation CO stand for?

active optical networks (AON) and passive optical networks (PON)

Two types of optical-distribution network architectures

optical network terminator (ONT)

component of FTTH internet access which directly connects to the home

optical line terminator (OLT)

component of FTTH which connects the ONT to the CO

physical medium

Examples of this include twisted-pair copper wire, coaxial cable, multimode fiber-optic cable, terrestrial radio spectrum, and satellite radio spectrum.

guided media and unguided media

Two categories of physical media; one uses the air and the other various forms of cable

Unshielded twisted pair (UTP)

Commonly used for computer networks within a building

geostationary satellites and low-earth orbiting satellites (LEO)

Two types of satellites used in communications

packets

this small chunk of data travels through communication links and packet switches

L/R

The time to transmit the packet in seconds where L is the number of bits and R is the transmission rate

store-and-forward transmission

Method in which a packet switch must receive the entire packet before it can begin to transmit the first bit of the packet onto the outbound link.

N*L/R

formula for end to end delay (d end-to end) where N is the number of links

output buffer

Packet switches have multiple links attached to them. For each attached link the packet switch has an ______ ______, which stores packets that the router is about to send into that link.

queuing delays

Variable delays that depend on the level of congestion in the network.

packet loss

This occurs when either a packet arriving or an already-queued packet is dropped.

forwarding table

Table that maps destination address to a routers outbound links

circuit switching and packet switching

The two fundamental approaches to moving data through a network of links and switches

circuit-switching

Method to move data trhough a network of links and switches which reserves communication sessions between end systems

frequency-division multiplexing (FDM) and time-division multiplexing (TDM)

Two types of implementations of circuit-swithing

time-division multiplexing (TDM)

reserves space for communication systems by time

frequency-division multiplexing (FDM)

reserves space for communication by partitioning the physical media into frequencies

bandwidth

the width of the band in FDM

customer and provider

In the network of networks an an access ISP is said to be the ________ and the global transit ISP is said to be the ________

tier-1 ISP

The top level ISP is known as a

regional ISP

The ISP which connects to a tier-1 ISP is known as a

Internet Exchange Point (IXP)

typically a stand-alone building with its own switches, which is a meeting point where multiple ISPs can peer together

processing delay, queuing delay, transmission delay, and propagation delay.

Different types of delays a packet may suffer collectively known as the total nodal delay

processing delay

The time required to examine the packet's header and determine where to direct the packet

queuing delay

packets experience this as it waits to be transmitted onto the link

transmission delay

the amount of time required to push all of the packet's bits into the link (L/R)

propagation delay

the time required to propagate from the beginning of the link to router B

d proc + d queue + d trans + d prop

formula for d nodal

N(d proc + d trans + d prop)

formula for d end-end (the end to end delay)

instantaneous througput

When transferring a large file from Host A to Host B across a computer network, this is the rate at which Host B is receiving the file at any instant of time

average throughput

When transferring a large file from Host A to Host B across a computer network, if the file consists of F bits and the transfer takes T seconds for Host B to receive all F bits this rate takes F/T bits/sec

bottleneck link

A link in a network which slows the throughput down

Application, Transport, Network, Link, and Physical

The five layers of the internet protocol stack

Application, Presentation, Session, Transport, Network, Link, Pysical

The seven layers of the OSI model

message

data in the application layer is known as a

segment

data in the transport layer is known as a

datagram

data in the network layer is known as a

frame

data in the link layer is known as a