Term
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Definition
"end devices, end systems, or end stattions"
able to accept inputs, process them and generate outputs in 1s & 0s
ex of outputs: texts, sound image, anything via computer network
ex of hosts: smart phones, pda's, video game consoles playstation & xbox, digital cameras,printers, copiers, fax machines
* it exchanges messages thru client server & peer to peer |
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Term
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Definition
ex: files, storage space, data bases, webpages, & CPUs processing capacity
*only needs a browser to take advantage of various resources offered by servers to control IT spending |
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Term
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Definition
has high performance to respond to request from client hosts
Ex: web browser, firefox- become universal client programs that allows communication with numerous server programs
*no dedicated client or server hosts
Ex: kazaa.com- my computer downloads files from other stations |
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Term
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Definition
has high performance to respond to request from client hosts
Ex: web browser, firefox- become universal client programs that allows communication with numerous server programs
*no dedicated client or server hosts
Ex: kazaa.com- my computer downloads files from other stations |
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Term
| Network Interface card "NIC" |
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Definition
is the mediator of messages between computer system & network- converts host -generated message units called packets to signals and releases them to network
* an electronic circuit board "adaptor or LAN card"
**Many users have 2 of these- ethernet LAN and wifi |
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Term
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Definition
"intermediary devices" enables transportation for messages between hosts in an effective and secure manner
Different types: modems, firewalls, multiplexes, csu/dub, hubs, switches, routers, bridges, and wireless access points
**differ from eachother by message processing speed & capacity message filtering & security provision |
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Term
intra-networking
"network devices" |
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Definition
| hubs, bridges,wireless access points & switches- provide end stations (ex client server and shared printers) with connectivity with IN network boundary |
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Term
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Definition
routers are primarily used to interconnect networks
*is formed when at least 2 networks are tied by the routers
***when 2 PC's exchange messages across 2 or more networks- this message process is called this |
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Term
half duplex
"Directionality of message exchange" |
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Definition
ex: hubs-
only 1 party is allowed to transmit at a time and the other party waits for its turn.(like a walkie talkie)
*has been replaced by full duplex |
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Term
full duplex
"directionality of message exchange" |
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Definition
ex: switches & routers- simultaneous flow of messages in both directions between network nodes
Ex: telephone |
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Term
network nodes
"network devices" |
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Definition
an umbrella concept to refer to both networking devices and hosts
networking devices (intermediary) plus hosts (end devices) |
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Term
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Definition
are wired or wireless communication media that enable connectivity of hosts & networking devices
* made up of cooper wires & optical fibers- pure glass or plastic
**electronic signals use copper wires or coaxial cables
***light signals & radio microwave signals use optical fibers in airspace |
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Term
access links
"network links" |
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Definition
| provide connectivity between hosts and networking devices |
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Term
trunk links
"network link" |
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Definition
interconnect intermediary devices (ex:router to router, router-switch, switch-switch
**is a point to point connection & carries traffic from more than 1 access link
***when hosts exchange messages through 2 or more intermediary devices- this takes one or more trunk links to enable end to end connectivity |
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Term
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Definition
ex: MS word and web browser
designed to improve communication:
Ex: emails, instant messaging, & internet phone |
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Term
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Definition
applications produce messages that need to be transported over the network
* contain real-time or interactive data, static file (web pages) or supervisory control info (handshaking between hosts) |
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Term
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Definition
| a generic name used to represent each unit of message |
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Term
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Definition
contains a collection of detailed rules of communication
2 types- synactic & semantic |
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Term
syntactic rules
"protocol, application" |
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Definition
rules regarding the format of a message in its construction
Ex: get http
host:FB |
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Term
semantic rules
"protocol, application" |
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Definition
rules concerned with the meaning or interpretation of a message
Ex" please send me the main page of FB using http |
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Term
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Definition
a standard protocol adopted by various web browsers and web server application
**skype has its own separate protocol |
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Term
Unicasting
"modes of communication" |
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Definition
a single source and singled destination of a message
ex: email, & web browsing |
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Term
broadcasting
"modes of communication" |
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Definition
results in a flood of a message from one node to all other nodes in simultaneous fashion
Ex: TV, Radio, &wifi |
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Term
multicasting
"modes of communication" |
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Definition
results in its concurrent delivery to a selected group of destinations
Ex: websites that offer audio or video streaming via the internet |
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Term
simplex
"directionality of message exchange" |
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Definition
messages flow only in 1 direction. from point A to point B
Ex: radio broadcasting and tv broadcasting
**not prevalent mode in computer networking |
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Term
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Definition
physical layout of a network
-location(degree of distribution)
-users (# of users)
-hosts (# of onstite hosts)
-applications(characteristic of application support |
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Term
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Definition
*simplest
* direct connection between 2 nodes |
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Term
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Definition
allows only a single station to transmit at a time to avoid collision
*works well for small networks
****does NOT exist anymore** |
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Term
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Definition
advantaged: handles high traffic volume in a good manner
* popular choice in creating high-speed wide area network (WAN) backbone based on fiber optic cables |
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Term
| star (hub & spoke) topology |
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Definition
advantage- easy to add & remove host stations from network and locate node or cable problems , easy to expand network scope
*disadvantage- the intermediary device brings down the network
**ethernet standard for LANs use this |
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Term
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Definition
arrangement in which all possible connections between networks nodes are directly linked
*used when the number of nodes are small
**partial mesh- offered certain level of link redundancy that makes network less vulnerable to link failures
***too expensive |
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Term
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Definition
| effective when many nodes have to be interconnected with reduced number of direct links |
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Term
Personal Area Network "PAN"
Classification of networks |
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Definition
small network coverage up to 10 meters
*bluetooth- exchange data without hard wiring
Ex: MP3 player, GPS, smart phones, printers |
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Term
ubiquitous computing
"PAN" |
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Definition
pervasive computing- small networking devices embedded in various objects can seamlessly & transparently interact with eachother to enable a host of innovative services
Ex: take pix of art from phone & get all the info. |
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Term
Local Area Network (LAN)
"classification of networks" |
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Definition
covers a confined area such as building to interconnect devices located within the boundary
-coverage scope larger than PAN
-P2P- host becomes both client & server
-client/server LAN- role of a host station is designated either a server or as a client(this dominates today)
***there is no one size fits all definition |
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Term
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Definition
oversized LAN that ties multiple buildings is termed this
- to form this- smaller LANs are joined by high speed networking devices |
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Term
| Metropolitan area network (MAN) |
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Definition
designed to cover a city
-mainly intended to interconnect LANs through land based or wireless standards with in a region
Ex: phone service (AT&T) and ISP(internet service providers) have ownership of the infrastructure to provide this |
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Term
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Definition
| has become a popular choice as the MAN platfom |
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Term
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Definition
| used as broadband access standard for wireless MAN services |
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Term
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Definition
spans out across a state, nation or international territory
-designed to interlink LANs, campus networks, MANs or even smaller WAN
-internet is its platform- largest global network |
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Term
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Definition
| indicate a corporate network composed of LANs that conjoined by WAN/MAN links |
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Term
data rate
capacity/speed
"measures of network performance" |
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Definition
| how fast data flows from point A to point B in one direction not both |
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Term
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Definition
| used to indicate data storage or memory capacity |
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Term
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Definition
| is the speed or data rate |
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Term
channel capacity
"data rate" |
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Definition
"bandwidth"or "rate speed" is the maximum theoretical data rate that can be achieved by network
**if measured in data rate- is a digital concept
**if by bandwidth - is analog concept
- driectly correlated because the bigger the bandwidth the BIGGER the channel capacity |
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Term
throughput
"capacity/speed" |
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Definition
refers to the actual data rate of a network achieves
*more realistic speed of a network and slower than a bandwidth/channel because of
--the effect of link distance
-transmisiion interferences
-internal/external noises |
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Term
delay
"measures of network performance" |
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Definition
| the amount of time a packet takes to travel between 2 networks nodes - measured in milliseconds |
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Term
propagation delay
"causes of delay" |
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Definition
| takes time between packets to travel between 2 located hosts |
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Term
delay @ hosts
"causes of delay" |
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Definition
source host should internally process the request message before releasing it in the network
(message into a pack then to an electrical signal) |
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Term
| delay at networking devices |
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Definition
| Intermediary devices such as routers & switches mediate packet delivery between hosts and their packet forwarding requires own internal processes including lookup of reference table |
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Term
the quality of service (QoS)
latency |
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Definition
| is performance guaranteed for real time or teleconferencing |
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Term
Permanency
Network Addressing |
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Definition
either temporary or permanent
-temporary address can be reclaimed or reassigned to another station if unused for certain durations
-permanent- on a nodes network card NIC ex MAc |
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Term
local address's
Accessibility |
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Definition
only recognized locally within a network and therefore are only used for packet transmissions within limited range
ex: MAC address intra- networking |
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Term
global address
Accessibility |
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Definition
utilized for packet forwarding beyond the limit of local boundary enabling inter-networking
Ex:IP address |
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Term
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Definition
| can be forwarded to the destination host over the internet |
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Term
private
network addressing |
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Definition
| used only within an organization or home network, has heightened security |
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Term
MAC Adress (Media Access control)
type of address scheme |
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Definition
intra-networking uses it
- is permanently printed on NIC |
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Term
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Definition
| the logical address because it does not have to be bound to node physcially |
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Term
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Definition
developed for the internet
-IETF responsible for the internet
*majority of popular standards at application transport and network layers are from this |
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Term
| OSI- open systems interconnection |
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Definition
-has 7 function layers
-from ISO |
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Term
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Definition
| in each layer of the network architecture, layer functions are formalized as this |
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Term
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Definition
contains a set of communication rules necessary to be followed by 2 network nodes to exchange messages
***except in physical layer |
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Term
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Definition
discrete message units when two nodes connect
"segment, packet, and frame"
*combination of data, header and traler
-data field- is where the actual message such as mail, voice or video is placed (additional overhead is added to the form of a header & trailer
-Overhead- includes info.such as source and destination adresses |
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Term
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Definition
-responsible for data signaling between nodes through wired or wireless
-implemented in hardware devices (NIC) |
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Term
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Definition
| focuses on providing transportation between nodes located withing a single network (Intra-networking) |
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Term
Switching
LAN data link
(Layer2) |
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Definition
| the delivery of frames for intra-networking & carried out purely based on MAC address |
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Term
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Definition
responsible for packet routing that crosses at least 2networks joined by one or more routers
2 things for support of the internetworking
1. packet creation and its routing across networks
2.perform supervisory functions |
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Term
packet creation & routing
(internet layer) |
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Definition
2 versions IPv4 & IPv6
-version 4- indicates the version of the packet
-header length- specifies header size
-diff-serv-designed to offer priority for real-time
-total length in octets-indicates the size of an entire packet
-identification-used to identify fragments of a IP packet
-time to live (TTL)-maximum number of routers a packet can pass through
-protocol in data field-refers to PDU inside an IP packets data
-header checksum- checks for error in header field |
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Term
packet routing
internet layer 3 |
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Definition
by routers over the internet
*packet passes through regardless of switches of switches or hubs along delivery path
-IP packet address does not change crossing multiple networks
-a router maps the destination IP address in a pack to its routing table
-find next hop router
-forwards the packet to the next hop router ot destination host
**IP adresses to cross networks in order to reach target host is what differntiates packet routing from MAC address |
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Term
IGMP "internet group management protocol
internet layer 3 |
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Definition
handles multicasting of IP packets
- can stream IP packets to a group of stations concurrently |
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Term
perform supervisory functions
internet layer 3 |
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Definition
ICMP- protocol designed to exchange supervisory messages
-Type value- supervisory function
0-echo reply
3- destination unreachable
8-echo request
* code- provides additional info regarding type - explains the reasons
-checksum- an error detection code that is computed over the entire ICMP PDU
"ping"- important in testing and troublehsooting network links & nodes - means the server is up and running and the link between the 2 nodes work normally
Traceroute- shows a packets routing path and delay latency in traversing the internet |
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Term
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Definition
- provide connection reliability between 2 end stations (hosts) engaged in communication
3 key functions
-provision of message integrity
-session management
-port management |
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Term
provision of message integrity
transport layer 4 |
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Definition
error control- intended to detect and correct data transmission errors ex: sending out an email
*flow control- used to regulate the transmission speed between 2 hosts with different processing capacity so that one host is not overwhelmed by the others onslaught
**UDP- is not a reliable protocol but is used for real time application messages such as video conferencing, online gaming & multimedia streaming |
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Term
handshaking
session management
Transport layer 4 |
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Definition
should be done prior to the exchange of messages
-represents a mutual agreement for the exchange
-TCP uses it
-UDP doesnt need it
*Ex: when downloading an image on a webpage this is used for each object on the page (HTTP,FTP, SMTP use it)
***when server host is too tied up _____ doesnt take place |
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Term
port management
Transport layer 4 |
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Definition
-who is the sending application, source, destination
3 groups
-wellknown
-registered
-private/dynamic |
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Term
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Definition
| has an IP address & port number- a client or server can determine the message source and direct it to a right application |
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Term
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Definition
defining communication rules (or protocols) between applications installed in hosts
Ex:email, voice over IP, instant messaging) |
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Term
command line interface
(CLI) |
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Definition
| preferred by many IT professionals because it offers more flexibility and control in device configuration |
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Term
Graphical User Interface
GUI |
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Definition
| more user friendly as it enables interactions with an OS primarily through a browser |
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Term
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Definition
- pure physical device that accepts incoming signals that carry frames, regenerates signal strength and shape, and repeats their transmission
-On receiving frames____ broadcasts them out to all connected ports except the entry port
-operate in half duplex
-have been replaced by switches due to congestion and security |
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Term
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Definition
-is a layer 2 device designed to divide a network to smaller manageable segments
-examines the MAC address of every frame arriving at its port and either passes or filters it based on information in the bridge table
-the bridge processing is highly intuitive in that, in the unicast mode,if the destination address of an incoming frame is in the same network segment then the frame is filtered (blocked) |
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Term
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Definition
interconnect network segments running the same standards
Ex: ethernet |
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Term
non-transparent bridge
"translational bridge" |
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Definition
when network segments running on different standards are bridged this is used
-translate the format of frames before they are handed over from one segment to another
-uses Wireless access point |
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Term
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Definition
most popular networking device for LANs
-forwards an arriving frame only to the port that directly or indirectly leads to its destination computer |
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Term
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Definition
| simple and inexpensive device that does not allow any modification of its configuration and is literally put into production as it is |
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Term
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Definition
| allows network administrators to configure and manage switch functions by interfacing with its operating system |
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Term
| store and forward switching |
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Definition
| when a frame begins to arrive at a port, the switch waits until the entire frame becomes available for switching |
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Term
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Definition
| it begins to forward the frame as soon as information (MAC address) necessary for switching becomes available |
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Term
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Definition
| all ports of a switch use the same delivery speed such as 100mbps |
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Term
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Definition
switch ports take advantage of different transmission speeds
-used when network traffic is centered on one or more ports |
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