Distr.syst.dhbw

Arrow Arrow

Komplett kostenfrei

studysmarter schule studium
d

4.5 /5

studysmarter schule studium
d

4.8 /5

studysmarter schule studium
d

4.5 /5

studysmarter schule studium
d

4.8 /5

Lerne jetzt mit Karteikarten und Zusammenfassungen für den Kurs Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg.

Beispielhafte Karteikarten für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg auf StudySmarter:

What are agreement protocols?

Beispielhafte Karteikarten für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg auf StudySmarter:

What is the two phase commit protocol?

Beispielhafte Karteikarten für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg auf StudySmarter:

What is one-phase commit protocol?

Beispielhafte Karteikarten für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg auf StudySmarter:

What is fault tolerance?

Beispielhafte Karteikarten für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg auf StudySmarter:

What are RESTful web services?

Beispielhafte Karteikarten für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg auf StudySmarter:

What are the properties of SOAP web services?

Beispielhafte Karteikarten für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg auf StudySmarter:

What is UDDI?

Beispielhafte Karteikarten für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg auf StudySmarter:

What is WSDL?

Beispielhafte Karteikarten für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg auf StudySmarter:

What is SOAP?

Beispielhafte Karteikarten für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg auf StudySmarter:

What are features of web services?

Beispielhafte Karteikarten für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg auf StudySmarter:

What are web services?

Beispielhafte Karteikarten für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg auf StudySmarter:

What is the bizantine agreement problem?

Kommilitonen im Kurs Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg. erstellen und teilen Zusammenfassungen, Karteikarten, Lernpläne und andere Lernmaterialien mit der intelligenten StudySmarter Lernapp. Jetzt mitmachen!

Jetzt mitmachen!

Flashcard Flashcard

Beispielhafte Karteikarten für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg auf StudySmarter:

Distr.syst.dhbw

What are agreement protocols?
  • n distributed systems sites (processors) compete and cooperate to achieve commont goals
  • often it’s necessary that sites reach mutual agreement
  • for instance data managers have to reach an agreement whether to commit or abort a transaction
  • in distributed commit a site has to know outcome of local commits
  • reaching agreement is easy in systems free from failures
  • voting and making decision according to majority vote (minimum, maximum, mean(etc.) number of votes)
  • in systems prone to failures we can have faulty processors sending conflicting values and preventing other processors to reach an agreement (previous methods don’t work)
  • processors now send values to other processors many times , refine values, and reach agreement in order to isolate effects of faulty processors – process called agreement protocol

Distr.syst.dhbw

What is the two phase commit protocol?
  • first phase
  1. – coordinator sends a VOTE-REQUEST message to all participants
  2. participants receive VOTE-REQUEST message and returns VOTE-COMMIT or VOTE-ABORT message to the coordinator
  • second phase
  1. coordinator receives votes and desides:
    • if all participants voted font to commit then coordinator sends GLOBAL-COMMIT to all participants
    • if, however, at least one voted to abort transaction then coordinator decides to abort the trasanction and multicasts a GLOBAL-ABORTmessage
  2. participants which voted to commit transaction wait for the final reaction from the coorinator and if they receive GLOBAL-COMMIT they execute transation and if receive GLOBAL-ABORT they abort it localy

Distr.syst.dhbw

What is one-phase commit protocol?
  • one-phase commit protocol is established by means of a coordinator which tells other involved processes (participants) whether or not to locally perform the operation
  • obvious drawback is that there is not way to tell coordinator that some of the participants cannot actually perform the operation

Distr.syst.dhbw

What is fault tolerance?
  • Fault tolerance is an important goal in distributed systems
  • ability of the system to recover from partial failures without serously affecting the overall performance
  • when a failure occurs the system should continue to operate in in an acceptable way while repairs are made
  • fault tolerance and reliable communication are strongly related
    • reliable client-server communication and group communication
  • atomicity is very important for distributed applications
    • distributed commit protocols – protocols that ensure that a group of processes jointly commit their local work, or collectively abort and return to a previous system state
  • redundancy is a key technique in achieving fault tolerance

Distr.syst.dhbw

What are RESTful web services?
  • Representational State Transfer (REST)
  • SOAP is messaging protocol while REST is a style of software architecture
  • REST is an architecture for distributed systems (in which text, video, graphics and other media are stored across a network and connected through hyperlinks
  • evertything that has an URI is a resource
  • RESTful approach is to use HTTP as an API not just as a transport protocol(in SOAP web services)
  • HTTP has its own methods that are suitable for CRUD operations
  • RESTful uses HTTP methods as onwn verbs
  • GET – Reads an existing resource
  • POST – Creates a new resource
  • PUT – Updates an existing resource
  • DELETE – Deletes an existing resource

Distr.syst.dhbw

What are the properties of SOAP web services?
  • SOAP web services become a well defined middleware technology for the Internet
  • the use of HTTP made them usable besides Internet
  • they become open standards implemented by all main programming languages
  • SOAP web services have been over-engineered
  • Additional burden that XML based SOAP messages put on network communication
  • this complexity of SOAP explains the current popularity of RESTful approaches

Distr.syst.dhbw

What is UDDI?
    • UDDI is an XML-based registry of Web services
      • UDDI search mechanism can focus on different criteria – business name, business category, location, URL, etc.
      • UDDI can be interogated using SOAP messages and should provide access to WSDL documents of services which are in it’s directory
      • UDDI registries are commonly found in companies where facilitate easer access to services

Distr.syst.dhbw

What is WSDL?

web services have to be described in order to clients know what they offer (what they do)

  • WSDL file is a description of what the web service does
  • WSDL file is an XML format for describing all the information needed to invoke and communicate with a Web service
  • WSDL contains:
    • Functional description – detail on how the Web service is invoked, and focuses on details of syntax of the message and how to configure protocols to deliver message
    • nonfunctional description – details secondary for the message such as security policy and additionaly instructions
  • WSDL is automatically generated

Distr.syst.dhbw

What is SOAP?

SOAP is an industry accepted W3C specification for ubiquitous XML distributed computing infrastructure

  • transport-independent messaging protocol
  • mechanism for defining the unit of communication
  • mechanism for error handling
  • messages are XML documents which follow a specific pattern
    • root element is known as Envelope element
    • header contains rooting data
    • body contains the actual message

Distr.syst.dhbw

What are features of web services?
  • Web service features
  • loosely coupled – each service exists independently of other services that make up application
  • easier integration – providing easier communication between organizations
  • service reuse – combining services to make a new functionality
  • Web services can be „roughtly“ devided into two categries:
  • SOAP based
  • REST style

Distr.syst.dhbw

What are web services?
  • web service is a distributed application whose components are executed on distinct devices
  • web services provide a common communication platform for applications built in various programming languages
  • language transparency is the key to web serviceinteroperability

Distr.syst.dhbw

What is the bizantine agreement problem?
  • Problem first defined and solved (under processor failures) by Lamport et al.
  • arbitrarily chosen processor (source processor) brodcast to other processors its initial value
  • Byzantine agreement should garantee that all nonfaulty processor agree on the same value
  • processors must exchange values through messages to reach a consensus
  • processors receive values and relay values to other processors
  • faulty processors may confuse other processors by sending conflicting values
  • Byzantine agreement problem should meet the following objectives:
  • Agreement – all nonfaulty processors agree on the same value
  • Validity – if the source processor is not faulty, then the common agreed upon value should be initial value of the source

Melde dich jetzt kostenfrei an um alle Karteikarten und Zusammenfassungen für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg zu sehen

Singup Image Singup Image
Wave

Andere Kurse aus deinem Studiengang

Für deinen Studiengang an der Duale Hochschule Baden-Württemberg gibt es bereits viele Kurse auf StudySmarter, denen du beitreten kannst. Karteikarten, Zusammenfassungen und vieles mehr warten auf dich.

Zurück zur Duale Hochschule Baden-Württemberg Übersichtsseite

Was ist StudySmarter?

Was ist StudySmarter?

StudySmarter ist eine intelligente Lernapp für Studenten. Mit StudySmarter kannst du dir effizient und spielerisch Karteikarten, Zusammenfassungen, Mind-Maps, Lernpläne und mehr erstellen. Erstelle deine eigenen Karteikarten z.B. für Distr.syst.dhbw an der Duale Hochschule Baden-Württemberg oder greife auf tausende Lernmaterialien deiner Kommilitonen zu. Egal, ob an deiner Uni oder an anderen Universitäten. Hunderttausende Studierende bereiten sich mit StudySmarter effizient auf ihre Klausuren vor. Erhältlich auf Web, Android & iOS. Komplett kostenfrei. Keine Haken.

Awards

Bestes EdTech Startup in Deutschland

Awards
Awards

European Youth Award in Smart Learning

Awards
Awards

Bestes EdTech Startup in Europa

Awards
Awards

Bestes EdTech Startup in Deutschland

Awards
Awards

European Youth Award in Smart Learning

Awards
Awards

Bestes EdTech Startup in Europa

Awards

So funktioniert's

Top-Image

Individueller Lernplan

StudySmarter erstellt dir einen individuellen Lernplan, abgestimmt auf deinen Lerntyp.

Top-Image

Erstelle Karteikarten

Erstelle dir Karteikarten mit Hilfe der Screenshot-, und Markierfunktion, direkt aus deinen Inhalten.

Top-Image

Erstelle Zusammenfassungen

Markiere die wichtigsten Passagen in deinen Dokumenten und bekomme deine Zusammenfassung.

Top-Image

Lerne alleine oder im Team

StudySmarter findet deine Lerngruppe automatisch. Teile deine Lerninhalte mit Freunden und erhalte Antworten auf deine Fragen.

Top-Image

Statistiken und Feedback

Behalte immer den Überblick über deinen Lernfortschritt. StudySmarter führt dich zur Traumnote.

1

Lernplan

2

Karteikarten

3

Zusammenfassungen

4

Teamwork

5

Feedback