Andmeside IRT 0030 loeng 719. okt. 2005

AndmesideIRT 0030

loeng 7 19. okt. 2005

Avo Ots

telekommunikatsiooni õppetoolraadio- ja sidetehnika instituut

[email protected]

Voo ülekanne

Infotransport

Paketiedastusteenus võrgus

Rakendus

Broadband

Norw ay

United States

Finland

Israel

Singapore

Sw eden

Netherlands

Sw itzerland

Japan

Denmark

Taiw an

Iceland

Canada

Hong Kong, China

Korea, Rep.

DSL

Cable

Other

Broadband penetration, subs per 100 inhab, by technology, 2003

8.4

9.3

9.4

9.6

10.1

10.8

11.4

11.4

11.7

13.3

13.4

14.0

14.7

18.0

23.3

Mobiilsus

High-endDatacom users

Mob

ilit

y

Processing capacityUser interface, e.g. screen-size

GateKeeperMCU

H.323 Clients

INTERNET

H.323 Videoconferencing

H.320

Gateway

ISDN

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 riskreduced service levels

for telephony?

SIP proxy,redirectserver

SQLdatabase

sipd

SIPH.323convertor

NetMeetingsip323

H.323

rtspd

SIP/RTSPUnified

messaging

RTSP media server

sipum

Quicktime

RTSP clients

RTSP

SIP conference

server

sipconf

T1/E1 RTP/SIP

Telephone

Cisco 2600 gateway

Telephoneswitch

Web based configuration

Web server

Cisco 7960

3Com

e*phone

sipc

Software SIP user agents

Hardware Internet (SIP)

phones

Pingtel

SNMP

Nõuded• Käideldavus

• Töökindlus

• Terviklikkus

• Konfidentsiaalsus

Saavutamine• Arusaamine protsessidest• Täiuslikumad seadmed• kvalifitseeritum personal• otstarbekam rutiin• pidev riskianalüüs

DNS-B(0.5.8.9.1.9.1.e164.arpa)

DNS-A(9.1.9.1.e164.arpa)

ENUM

proxy.comINVITE

INVITE

Answer = sip:n

iel@pro

xy.com

“(919) 850-5500"

Qu

ery

0.0.

5.5.

0.5.

8.9.

1.9.

1.e1

64.a

rpa

Au

tho

rity

= D

NS

-B

Query 0.0.5.5.0.5.8.9.1.9.1.e164.arp

a

Prioriteedid Ethernet kaadris

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 serveris also client of origin

origin server

Fairness goal: if K TCP sessions share same bottleneck link of bandwidth R, each should have average rate of R/K

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness

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 throughputConnect

ion 2

th

roughput

congestion avoidance: additive increaseloss: decrease window by factor of 2

congestion avoidance: additive increaseloss: decrease window by factor of 2