Chapter 13: internet and distributed application services

Internet Inter -ORB Protocol (IIOP)

A component message - passing protocol

standard web protocols and services

Protocol- An optional header specifying the resources access protocol Host-the IP address or register name of an Internet host computer or device Port- An optional port number that, together with an IP address, specifies a socket Resource- The complete pathname to a resources on the host

Lightweight diretory access protocol( LDAP)

a basis for X.500 standards, it is which the Internet Engineering Task Force (IETF) adopted as sa formal internet standard. LDAP is a widely used, although not all products have all features of the most recent updates

Component object model plus (COM+)

a microsoft specification for component interoperability, has its roots in older micorosoft specifications, including object linking and embedding (ole) and the component object model (COM)

remote procedure call (RPC)

a protocol where a process on one machine can call a process on another machine. As with function or procedure calls in a single program, the calling process follows these steps: 1) pass parameters to the called process 2) wait for the called process to complete its task 3) Accept parameters back from the called process 4) resume execution with the instruction following the call

dynamic connections

a resources user asks fro a resource, and if it isn't found in the local resources registry, the resource locator searches for it in external locations

object request broker (ORB)

a service that maintains a component directory and routes messages between components

before accesing remote resources..

a user or system administrator must know the server and resource names to create a static connection within the resource registry

view layer

accepts user input and formats and displays processing results

file transfer protocol(FT)

and older web protocol, which HTTP is an extention. It specifies a client/server request and reponse language for copying files from one internet to host to another.

n layers or n tier architecture

architectures having more than three layers

static connection

are difficult to initialize and maintain because the OS must be configured to establish a connection each time it starts

directory services

are integral components of all operating systesm

higher levle protocols

are often layered above interprocess communication protocols

layers

can also be replicated in different forms. A single business logic layer might interact with multiple view layers from different applications

connections to remote resources

can be static or dynamic

business logic layer

carries out the rules and procedures of business processing

tiers:

data layer, business logic layer, view layer

Platform as a service (PaaS)

describes an architectural approach in which an organization rents acces to system software and hardware on which it installs its own application software and other services

directory services

describes middleware: 1) stores the name and network address of distributed resources 2) responds to directory queries 3) accepts directory updates 3) synchronizes replicated or distributed directory copies

middleware

describes software that glues together parts of a client/server of multitier application. Its a wide ranging system software category because applications connection and communication requirements vary.

distributed computing or distributed processing

distributing parts of an information system across many computer systems and locations

protocol advantage

divide the task of network interaction into several well defined pieces that can be implemented installed and updated separately. 2 2) provide flexibility needed to keep up with rapid changes in protocol standards 3) insulate application programs and many portions of the OS from detail of low level network communication protocols and physical network implementation, which ensure software portability across a wide range of network protocols and transmission data.

three layer architecture or three tier architecture

divides application software into the following client and server processes called layers or tiers

Simple mail transfer protocol( SMTP)

earliest email protocol, which defines how text messages are forward and routed between internet hosts.

peer to peer applciation process

either side of the applicaton can create it. A client or peer opens a named pipe as a network resources and reads or writes it as though it were a file on a shared directory. A server or peer on teh machine where the name pipe was created reads and writes the pipe as though it were a local file

Extensible Markup Language(XML)

extends HTML to describe the structure, format, and content of documents

Multipurpose Internet Mail Extensions (MIME)

extension of SMTP, its a protocol to allow including nontext files in email messages. Also used in HTTP and XML

second or third premises

if every local resources might be needed by remote users or processes, every computer is potentially both a client a server

advatages of P2P

include improved scalability and reduicng the number of computer and network connectiosn needed to support and application

Hyptertext transfer protocol (HTTP0

is a companion protocol to HTML and XML that specifies the language by which clients request doscuments and how servers respond to those requests

client/server architecture

is a method of organizing software to provide and access distributed information and computing resources. It divides software into two classes: client and server.

named pipe

is a pipe with two additional features 1) a name thats permanently placed in a file system directory 2) the capability to communicate between process on different computers

pipe

is a region of shared memory through which multiple processes executing on the same machine can exchange data. A) commonly used for communication between OS components, for queuing requests to an OS service and for exchanging messages between components in a large program.

HTTPS

is a secure version of HTTP that encrypts HTTP requests and responese. HTTP/2 is the latest HTTP Version

component

is a standardized interchangeable software module with the folowing characteristic 1)is executable 2) has a unique identifier 3) has a well known interface

socket

is a unique combination of an IP address and a port nunmber separated by a colon

software as a service (SaaS)

is a web based architectural approach in which users interact via web browser or other web enabled view layer with application software provided by a third party.

Secure Shell (SSH)

is an improved version of Telnet that encrypts data flowing between client and server

Simple Object Access Protocol (SOAP)

is an open minded, developed by the world wide web consortium for distributed object interaction that attempts to address the shortcoming of both CORBBA and COM+

remote desktop protocol(RDP)

is proprietary microsoft protocol that supports remote command layers interface with a full graphical user interface

Infrstructure as a service (Iaas)

is similar in amn yways to PaaS but the service provider supplies little or no system software.

OS

manages data movement between processe and shared memory region

data layer

manages stored data, usually in databases

server

manages system resources and provides access to theses resources through a well defined commnication interface

resource rgistry

resource locater maintains a local registry containing the names and locations of known resources and services. When local service provider processes are started they register themselves with the resource locator, which updates the resourse registry accordingly. Resources requests are checked against this registry.

resources distributed across network nodes...

resource users and providers must have some way of finding on another

distributed computing environment (DCE)

services into COM and called the resulting specification the distributed component object model (Dcom)

location transparency or network transparency

software and user interfaces are simplified by providing a common method of accessing both local and remote resources.

protocol stack

software implementing the transport, internet, and network interface layers of this model is commonly called protocol stack

common object request broke architecture (CORBA)

specifies the middleware objects use to interact across, networks and has these two key components

network OS directiories

stores information about: 1) registers users and their permissions to access directory objects 2) shared hardware resources such as printers 3) shared files, databases, and programs 3) computer systems and specialized hardware devices such as network storage appliances

cloud computing

summarizes new approaches to distributing and accessing software and hardware services across the internet.

peer to peer (P2P) architecture

the roles of client and server are combines into a single application or group of related applications

variation of client/server architecture

three layer architecture or three tier architecture

Post Office Protocol 3 (POP3) , Internet MEssage Access Protocol 4 (IMAP4)

today's email server is base on one or both. POP3 standardizes the interaction between email clients and servers so that client and server can run on different internet hosts. IMAP4 extends POP3 to permanently stores and manage e mail messages on the server which enables users to access stored e mail from any internet host.

Domain Name System (DNS0

used on the internet, is one example of dynamic connection. Every IP packet carries the destination node's IP address. Because nearly all remote services accesses uses internet protocols, finding the IP addresses of servers and P@P nodes with needed resources must be the first step to sending access request messages.

telenet protocol

users on one internet host can interact with the OS commnad layer of another host. Emulates a charcter based display device and keyboard and is limited to interacting and command line interfaces such as Windows Cmd.exe and the UNIX Bourne Shell

client

uses the communication interface to request resources and the server responds to these requests

service -oriented architecture (SOA)

was cointed to describe the design philosophy

named pipe creations

when its created, a directory entry is also created in the local file system. Programs can read or write the name pipe as they would read or write an ordinary file. Typically the server side of a client/server application creates the named pipe.

lower level P2P protocols and standards

which enable processes to communicate synchronously across a network. System software often uses these protocols to exchange data and coordinate activities. Distributed applications usually use higher level protocols,