Distributed Naming & DNSGoalsLookupsNamespaceDelegationRecordsCachingMIT OpenCourseWarehttp://ocw.mit.edu 6.033 Computer System Engineering Spring 2009 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms.Distributed Naming & DNSNet Layer Æ e.g. IP addresses1) Convenience2) ModularityDNS Æ Host names Æ RecordsGoals“Tel. book model”Central serverDistrib. database1) Scalability2) ReliabilityLookupsName Æ Record : dns_resolve(dnsname)- App-specified- DNS configSearchNamespaceRootcom edu net org gov …-Hierarchical- Structuredmit …www csail eecs{INFO}X {INFO}Delegation• Root• Top-Level Domain (TLD)• Domains anywhere in treeRecordsA : AddressMX :CNAME : “Synonym”NS : Name server recordAny name serverROOT nsAppStub resolverx.csail.mit.edux …EDU nsreferralmit.edu ns1) Bootstrap- Root identity-Stub?-DHCP- Manual2) PerformanceCaching- Recursive resolution- Expiration
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