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Chapter 4 Networking and the Internet Introduction to CS 1st Semester, 2012 Sanghyun Park Outline Network Fundamentals Internet World Wide Web Internet Protocols Security (will be covered in 12th week) Network Classification (1/3) Two broad categories Ownership ____ (Local Area Network): normally consists of a collection of computers in a single building or building complex, e.g., university campus ____ (Wide Area Network): links machines that may be in neighboring cities or an opposite side of the world Public domain _____ network (Internet) Private entity ______ network or _________ network Network ________ (pattern in which machines are connected) Ring, bus, star, irregular Network Classification (2/3) The machines are connected in a ________ fashion The machines are all connected to a common communication line called a _____ Network Classification (3/3) One machine serves as a ____ to which all the others are connected The machines are connected in what appears to be a _________ manner Bridge and Router (1/2) At times it becomes necessary to ________ two existing networks When the networks are compatible, this can be done by merely connecting the networks by a coupling device called a _______ When two networks are connected via a bridge, the result is simply a larger _______ network It is often necessary to join two networks whose characteristics are not compatible In this case, the two networks must be connected in a manner that builds a network of networks, which is known as an _______ The connection between two networks to form an internet is handled by a machine known as a ______ Bridge and Router (2/2) Inter-Process Communication Client-server One server, many clients Server must execute _____________ _______ initiates communication Peer-to-peer Two processes communicating as _______ Peer processes can be ___________ Client/Server Model C/S Model Compared To Peer-To-Peer Model Distributed Systems Systems with parts that run on _________ computers Infrastructure usually provided by standardized toolkits Examples include: Enterprise JavaBeans from ________________ .NET framework from ___________ The Internet A network of networks ________ An example of an internet is the _________ Originated from a research program initiated in 1973 by the Defense Advanced Research Projects Agency (DARPA) Internet is a combination of WANs and LANs involving maybe millions of machines Internet Topology (1/2) The Internet can be viewed as a collection of _______, each of which is relatively small internet operated by a _______ organization To establish a domain, the entity desiring the domain must register with ______ (Internet Corporation for Assigned Names and Numbers) A domain is attached to the existing Internet via a _______ that connects a network in the domain to a network already in the Internet This particular router is called the domain’s _________ The gateways of a number of domains can be connected to form a regional network of gateways Internet Topology (2/2) A typical approach to connecting to the Internet Internet Addressing (1/2) Each machine in the Internet is assigned a unique address, called an ___________ Each IP address is a pattern of _______ consisting of two parts: Identify the domain (______________) Identify the particular machine within the domain (_____________) Network identifier is assigned by ICANN at time of domain establishment and registration (guarantees __________ of network identifier) The host address is assigned by the domain’s local authority Example 192.207.177 (network identifier of Addison-Wesley publishing co.) 192.207.177.133 (a machine within this company) Internet Addressing (2/2) ICANN assigns each domain a unique __________ address known as domain name (edu, gov, org, com, … first-level domains) Break domain into sub-domains We need a ________ between numeric addresses and mnemonic addresses (each local authority maintains such _________) Directory is implemented within the domain in the form of a server called a ____________ (DNS Domain Name System) Name server provides ________ for mnemonic addresses to obtain the corresponding numeric addresses World Wide Web (1/3) _________ is a text containing words, phrases, or images that are linked to other documents When hypertext contains sounds and video, it is called __________ Reader of hypertext documents can explore related documents A _____ of related information is formed Web that has evolved on the Internet spans the entire globe and is known as ________________ Request Client machine Browser Server machine Serves web pages Reply World Wide Web (2/3) Each document is identified by a _________ address This unique address is called a _____ (Uniform Resource Locator) The URL allows to identify the ______, the ________ in use, and a desired _________ Sometimes a URL does not explicitly identify a document, in such case a predetermined document is often returned (usually a ______ page) World Wide Web (3/3) A hypertext document contains several ________ that describe How the document should _______ within the browser Which items within the document are to be ______ to other documents Systems of markers known as Hypertext Markup Language (____) Finding information on the WWW ________ Engines Layered Approach to Internet Software (1/2) A principal task of network software is to provide the ___________ required for ___________ message from one machine to another Package-shipping example The transportation of the gift would be carried out by a three-level hierarchy: (1) the _____ level, (2) the ________ company, and (3) the ________ Layered Approach to Internet Software (2/2) The Internet software has _____ layers rather than three: TCP/IP Protocol Suite (1/2) The _______ protocol suite is a collection of protocols used by the Internet to implement the four-level hierarchy just described Actually, TCP (Transmission Control Protocol) and IP (Internet Protocol) are the names of only two of the protocols in this collection TCP/IP protocol suite provides two ways of implementing the _______ layer: TCP and UDP (User Datagram Protocol) The _________ layer may choose to send data via a TCP or UDP IP is the Internet’s standard for the _________ layer TCP/IP Protocol Suite (2/2)