26 Kommunikatsiooniteenuste arendus IRT0080 Loeng 2/2008 Avo Ots telekommunikatsiooni õppetool, TTÜ raadio- ja sidetehnika inst.

The Internet Every machine transparently connected to every other

28 Kasutuskava muutus One computer/phone, many users One computer/phone, one user Many computers/phones, one user anywhere, any time any media right place (device), right time, right media ~ ubiquitous computing  embedded VoIP mainframe era home phone party line PC era cell phone era

29 Implementation Applications OS Applications OS Multi layer implementation -Breaking down into smaller components -Easier to implement Single layer implemen- tation Applications OS Communication Applications OS Communication

30 Võrgu tipptase

31 Datagramm vsVirtuaalahel

32 Multiple Access Protocols Multiple access protocols Contention-basedConflict-free Random access Collision resolution FDMA, TDMA, CDMA, DQDB, etc ALOHA, CSMA WINDOW, etc DQDB: Distributed Queue Dual Bus

33 Throughput Slotted Aloha Aloha G S

34 Vastastikused häired

35 Standards (3) Sending Client Receiving Client Sender’s Mail Server Receiver’s Mail Server Message RFC 822 or 2822 HTML body UNICODE Message Body Format Standard

36 Internet IP Network Tugijaam Võrgu ülesehitus Gateway Raadioliides Telefonivõrk Gateway End-to-End IP

37 MMC (Measure, Model, and Control) Ülesehitus Liiklus Muutuste tegemine Käigusolev võrk Models, tools, scripts, databases measure control Võrguhaldus Andmehõive Häälestus

38 ApplicationsApplications Call Processing InfrastructureInfrastructure Clients IP SoftPhone PSTN gateways Analog phone support IP Network PSTN Directory Call Processing Voice Mail, UMS Intelligent Contact Manager IP IVR, IP AA Apps Engine Voice Portal ICM Collaboration Video Paketipõhine telefonilahendus GK

39 Message Transmission Example

40 TCP

41 The Problem only nodes on the same physical/link layer network could communicate

42 Solution Gateways

43 Standards (1) SMTP To Send SMTP To Send Sending Client Receiving Client Sender’s Mail Server Receiver’s Mail Server Simple Mail Transfer Protocol (SMTP) to transmit mail in real time to a user’s mail server or between mail servers Sender-initiated

44 Standards (2) Sending Client Receiving Client Sender’s Mail Server Receiver’s Mail Server POP or IMAP To Receive POP or IMAP to download mail to receiver when the receiver is next capable of downloading mail. Receiver-initiated

45 Lingid ftp://ftp.prenhall.com/pub/esm/sample_chapters/cs /stallings/index.html