4 - Internet Architectures Flashcards
Computer Networks
A computer network is a collection of computers and devices connected for the purpose of electronic data
communication that allows them to share information and services
Private Networks
requires users to obtain permission to gain access; Either manually by a network administrator or via password
Public Networks
access is not restricted (e.g., the internet)
World Wide Web
information space (on the Internet) in which global identifiers called Uniform Resource Identifiers (URI) identify the items of interest, referred to as resources
WAN
Wide Area Network:
Connects computing devices over a large geographical distance or even those across the globe
MAN
Metropolitan Area Network:
Interconnects computing devices within a city or a metropolitan area
LAN
Local Area Network:
Connects computing devices within the same room or building
URI
A Uniform Resource Identifier (URI) identifies a resource either by location, or a name, or both
URL
Uniform Resource Locator
- Is a URI that identifies a resource and also provides the means of location of the resource by describing the way to access it
URN
Uniform Resource Name
- Is a URI that includes a name within a given space , but does not describe how to access the resource
Tier 1 ISPs
Are operated by national telecommunication
companies (e.g., Deutsche Telekom, AT&T);
Tier 1 networks exchange data directly with each other
Tier 2 ISPs
- They exchange Internet traffic through peering agreements and purchase Internet traffic from Tier 1 ISPs
- Data exchange is done at neutral data centers, that is,
data centers in shared use by multiple ISPs, called
Internet Exchange Points (IXPs) or MXP
Tier 3 ISPs
- Delivers Internet access to residential homes and businesses
- Strictly purchases Internet traffic from higher tier networks
POP
Point of Presence
- Local access point of an ISP where the telecommunication lines from commercial or domestic buildings are connected to the ISP’s network
- Often located within the facility of a telecommunications
provider responsible for the infrastructure to the customer
Internet Society (ISOC)
Provides organizational structure to support the process of Internet standard development
Internet Engineering Task Force (IETF)
Develops and maintains voluntary Internet standards (e.g., TCP/IP)
Internet Corporation for Assigned Names and Numbers (ICANN)
Responsible for the IP address space allocation and management of the domain name system
Word Wide Web Consortium (W3C)
- Responsible for developing interoperable technologies for the WWW
- Examples: HTML, XML, CSS, and SOAP
Internet Protocol Suite (TCP/IP)
The Internet protocol suite is a set of protocols that enables Internet communication by specifying data transmission, addressing, and routing
- defines how data should be packaged, addressed, sent, routed, and received
Application Layer
provides applications with standardized interfaces that allow them to send data to other applications or receive data from them via a network
Transport Layer
responsible for the correct transfer of data between network nodes, independent of their application, specific data structures, and underlying network
- TCP ensures that, for instance, data arrive in the order they were sent, that they arrive correctly, that duplicate data are discarded, and that data lost in transit are resent
UDP
provides highly efficient but less reliable data transmission and has no error-recovery mechanism
Transmission Control Protocol (TCP)
- TCP is a reliable service which guarantees that all bytes are received in the right order
- This is done by using positive acknowledgements (ACK) with re transmission; receiver responds with an ACK for ever data packet he receives
- Sender retransmits packets for missing ACKs after a given time
Network Layer
responsible for transporting data between the right nodes within a network or across multiple networks; node addressing and data routing