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Published byEthel Cain Modified over 9 years ago
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Andmeside IRT 0030 loeng 719. okt. 2005 Avo Ots telekommunikatsiooni õppetool raadio- ja sidetehnika instituut avots@lr.ttu.ee
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Voo ülekanne Infotransport Paketiedastusteenus võrgus Rakendus
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Broadband
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Mobiilsus High-end Datacom users Mobility Processing capacity User interface, e.g. screen-size
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GateKeeper MCU H.323 Clients INTERNET H.323 Videoconferencing H.320 Gateway ISDN
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Reliability WAN Is NT as stable as a proprietary operating system? Why shouldn’t the data network be resilient enough for voice needs? Will management risk reduced service levels for telephony?
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SIP proxy, redirect server SQL database sipd SIPH.323 convertor NetMeeting sip323 H.323 rtspd SIP/RTSP Unified messaging RTSP media server sipum Quicktime RTSP clients RTSP SIP conference server sipconf T1/E1 RTP/SIP Telephone Cisco 2600 gateway Telephone switch Web based configuration Web server Cisco 7960 3Com e*phone sipc Software SIP user agents Hardware Internet (SIP) phones Pingtel SNMP
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Nõuded Käideldavus Töökindlus Terviklikkus Konfidentsiaalsus Saavutamine Arusaamine protsessidest Täiuslikumad seadmed kvalifitseeritum personal otstarbekam rutiin pidev riskianalüüs
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DNS-B (0.5.8.9.1.9.1.e164.arpa) DNS-A (9.1.9.1.e164.arpa) ENUM proxy.com INVITE Answer = sip:niel@proxy.com “(919) 850-5500" Query 0.0.5.5.0.5.8.9.1.9.1.e164.arpa Authority = DNS-B Query 0.0.5.5.0.5.8.9.1.9.1.e164.arpa
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Prioriteedid Ethernet kaadris
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Web cache – proxy server Network entity that satisfies HTTP requests on behalf of a client. Keeps copies of recently requested objects in its own disk storage. Content distribution. HTTP request HTTP response HTTP request HTTP response client proxy server is also client of origin origin server
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Fairness goal: if K TCP sessions share same bottleneck link of bandwidth R, each should have average rate of R/K TCP connection 1 bottleneck router capacity R TCP connection 2 TCP Fairness
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Why is TCP fair? Two competing sessions: Additive increase gives slope of 1, as throughout increases multiplicative decrease drops throughput proportionally R R equal bandwidth share Connection 1 throughput Connection 2 throughput congestion avoidance: additive increase loss: decrease window by factor of 2 congestion avoidance: additive increase loss: decrease window by factor of 2
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