Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13From Coulouris, Dollimore, Kindberg and BlairDistributed Systems: Concepts and DesignEdition 5, © Addison-Wesley 2012Slides for Chapter 13: Name ServicesInstructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Figure 13.1Composed naming domains used to access a resource from a URLhttp://www.cdk3.net:8888/WebExamples/earth.htmlURLResource ID (IP number, port number, pathname)Network address2:60:8c:2:b0:5a fileWeb server55.55.55.55 WebExamples/earth.html8888DNS lookupSockethttp://www.cdk5.net:8888/WebExamples/earth.html2:60:8c:2:b0:5aInstructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Figure 13.2Iterative navigationClient123A client iteratively contacts name servers NS1–NS3 in order to resolve a nameNS2NS1NS3NameserversInstructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Figure 13.3Non-recursive and recursive server-controlled navigation123512344A name server NS1 communicates with other name servers on behalf of a clientclient clientRecursiveserver-controlledNS2NS1NS3NS2NS1NS3Non-recursiveserver-controlledInstructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Figure 13.4DNS name serversNote: Name server names are in italics, and the corresponding domains are in parentheses. Arrows denote name server entries a.root-servers.net(root)ns0.ja.net(ac.uk)dns0.dcs.qmul.ac.uk(dcs.qmul.ac.uk)alpha.qmul.ac.uk(qmul.ac.uk)dns0-doc.ic.ac.uk(ic.ac.uk)ns.purdue.edu(purdue.edu)ukpurdue.eduic.ac.ukqmul.ac.ukdcs.qmul.ac.uk*.qmul.ac.uk*.ic.ac.uk*.dcs.qmwul.ac.uk* .purdue.eduns1.nic.uk(uk)ac.ukco.ukyahoo.comInstructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Figure 13.5DNS resource recordsRecord type Meaning Main contentsA A computer address IP numberNS An authoritative name server Domain name for serverCNAME The canonical name for an alias Domain name for aliasSOA Marks the start of data for a zone Parameters governing the zoneWKS A well-known service description List of service names and protocolsPTR Domain name pointer (reverselookups)Domain nameHINFO Host information Machine architecture and operatingsystemMX Mail exchange List of < preference, host > pairsTXT Text string Arbitrary textInstructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Figure 13.6DNS zone data recordsdomain name time to live class type value1D IN NS dns01D IN NS dns11D IN NS cancer.ucs.ed.ac.uk1D IN MX 1 mail1.qmul.ac.uk1D IN MX 2 mail2.qmul.ac.ukdomain name time to live class type value www 1D IN CNAME apricot apricot 1D IN A 138.37.88.248 dcs 1D IN NS dns0.dcsdns0.dcs 1D IN A 138.37.88.249dcs 1D IN NS dns1.dcsdns1.dcs 1D IN A 138.37.94.248dcs.qmul.ac.ukdcs.qmul.ac.ukdcs.qmul.ac.ukdcs.qmul.ac.ukdcs.qmul.ac.ukInstructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Figure 13.7GNS directory tree and value tree for user Peter.SmithUK FRACQMWDI: 322Peter.SmithpasswordmailboxesDI: 599 (EC)DI: 574DI: 543DI: 437Alpha GammaBetaInstructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Figure 13.8Merging trees under a new rootECUK FRDI: 599DI: 574DI: 543NORTH AMERICAUSDI: 642DI: 457DI: 732#599 = #633/EC#642 = #633/NORTH AMERICAWell-known directories:CANADADI: 633 (WORLD)Instructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Figure 13.9Restructuring the directoryECUK FRDI: 599DI: 574DI: 543NORTH AMERICAUSDI: 642DI: 457DI: 732CANADADI: 633 (WORLD)#633/EC/USUS#599 = #633/EC#642 = #633/NORTH AMERICAWell-known directories:Instructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Figure 13.10X.500 service architectureDSADSADSADSADSADSADUADUADUAInstructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Figure 13.11Part of the X.500 Directory Information Tree... France (country) Great Britain (country) Greece (country) ...BT Plc (organization) University of Gormenghast (organization)... ...Department of Computer Science (organizationalUnit)Computing Service (organizationalUnit)Engineering Department (organizationalUnit)......X.500 Service (root)Departmental Staff (organizationalUnit)Research Students (organizationalUnit)ely (applicationProcess)......Alice Flintstone (person) Pat King (person) James Healey (person) ...... Janet Papworth (person)...Instructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Figure 13.12An X.500 DIB EntryinfoAlice Flintstone, Departmental Staff, Department of Computer Science, University of Gormenghast, GBcommonName Alice.L.Flintstone Alice.Flintstone Alice Flintstone A. Flintstonesurname FlintstonetelephoneNumber +44 986 33 4604uid alf mail [email protected]@dcs.gormenghast.ac.ukroomNumber Z42userClass Research