Transcript Teenus_8_2
Kommunikatsiooniteenuste arendus IRT0080 Loeng 2/2008 Avo Ots telekommunikatsiooni õppetool, TTÜ raadio- ja sidetehnika inst. [email protected] 26 The Internet Every machine transparently connected to every other Kasutuskava muutus One computer/phone, many users mainframe era home phone party line PC era cell phone era One computer/phone, one user Many computers/phones, one user ~ ubiquitous computing embedded VoIP anywhere, any time any media right place (device), right time, right media 28 Implementation Applications Applications OS Applications OS OS Applications OS Single layer implementation Multi layer implementation -Breaking down into smaller components -Easier to implement 29 Võrgu tipptase 30 Datagramm vs Virtuaalahel 31 Multiple Access Protocols Multiple access protocols Contention-based Conflict-free Random access Collision resolution ALOHA, WINDOW, etc CSMA FDMA, TDMA, CDMA, DQDB, etc DQDB: Distributed Queue Dual Bus 32 Throughput 0.5 0.4 0.368 0.3 S Slotted Aloha 0.2 0.1 00 0.184 Aloha 2 4 G 6 8 G 33 Vastastikused häired Interference Margin (dB) Interference Margin (dB) and Load Factor 25 20 15 10 5 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Load Factor 34 E-Mail Standards (3) Sender’s Mail Server Receiver’s Mail Server Message Body Format Standard Sending E-Mail Client Message RFC 822 or 2822 HTML body UNICODE Receiving E-Mail Client 35 Võrgu ülesehitus Internet Gateway Telefonivõrk IP Network Gateway Tugijaam Raadioliides End-to-End IP 36 MMC (Measure, Model, and Control) Võrguhaldus Models, tools, scripts, databases Häälestus Andmehõive Liiklus Ülesehitus Muutuste tegemine measure control Käigusolev võrk 37 Paketipõhine telefonilahendus Collaboration Applications Call Processing Video Voice Mail, UMS Call Processing Voice Portal GK PSTN Infrastructure IP IVR, IP AA Apps Engine Intelligent ICM Contact Manager IP Network Directory • PSTN gateways • Analog phone support Clients IP SoftPhone 38 Message Transmission Example 39 TCP 40 The Problem • only nodes on the same physical/link layer network could communicate 41 Solution Gateways 42 E-Mail Standards (1) SMTP To Send SMTP To Send Sender’s Mail Server Sending E-Mail Client 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 Receiving E-Mail Client Sender-initiated 43 E-Mail Standards (2) Sender’s Mail Server Sending E-Mail Client Receiver’s Mail Server POP or IMAP to download mail to receiver when the receiver is next capable of downloading mail. POP or IMAP To Receive Receiving E-Mail Client Receiver-initiated 44 Lingid http://en.wikipedia.org/wiki/Client_server http://en.wikipedia.org/wiki/Application_server ftp://ftp.prenhall.com/pub/esm/sample_chapters/cs /stallings/index.html http://www.williamstallings.com 45