1. Andmeside IRT 0030 loeng 5 28. sept. 2005
Avo Ots
telekommunikatsiooni õppetool raadio- ja sidetehnika instituut

2. Paketiedastusteenus võrgus
Voo ülekanne
Infotransport
Paketiedastusteenus võrgus
Rakendus

3. Application layer protocol Transport protocol
Data loss
Bandwidth
Time sensitive
Application layer protocol
Transport protocol
File transfer No
Elastic
FTP
TCP
SMTP
Web documents
Elastic, Kbps
HTTP
Real-time audio/video
Yes
Kbps, Mbps
Yes, 100s of Msec
Proprietary
TCP or UDP
Stored audio/video
Yes, sec
Proprietary, NFS
Interactive games
Kbps
Financial applications
Both
Transmission Control Protocol
User Datagram Protocol
TCP: guarantee: deliver all data; no guarantee: rate, delay; connection; congestion control
UDP: no guarantee: deliver all data, order, delay; no connection; no congestion control

4. QoS
QoS is the ability of a network to service an application efficiently, without affecting its function or performance.
In essence, QoS is an application insurance policy.

5. QoS tagamine QoS is a set of techniques to manage:
Bandwidth - The perceived width of the pipe
Delay - The perceived length of the pipe
Jitter - The perceived variation in the length
Packet Loss - The perceived leak in the pipe
Began in fall of 1999
Equipment and lines located in Denver
Only 3 members
Cost of internet connectivity went up/no free rides
Long battle to get multiple carriers
BPOP is composed of NOAA/NIST and NCAR
Gives NCAR a back-door internet access in Boulder

6. Ribalaiuse puudus Many items may effect the delay of a packet
Speed Mismatch
Aggregation
Data Transfer

7. Ribalaiuse sobitamine
Ethernet
Switch
1000Mbps
100Mbps

8. Agregeerimine
1000Mbps
1000Mbps

9. QoS tagamine Differentiated Services (DiffServ)
RFC-2474,2475,2597,2598
Simply defines service levels
Gold
Silver
Bronze
Per-Hop Behaviors (PHB)

10. QoS disain Categorize WAN/LAN Links Define classes of service
Usually 3-5 different levels
Redundancy?
Switch changes
Router changes
Host changes

11. QoS implementeerimine
Set Queuing on Ethernet Switches
Set Queuing/DiffServ on Routers
Phased approach
Test bed
Switches
Routers

12. Technology &Services 3G WiMAX WiFi Large Network Coverage Simplicity
QoS
Full Mobility

13. Over-Provisioning Traditional approach for data networks…
Bandwidth Over-Provisioning
Traditional approach for data networks…
No mechanism for QoS
Is actually best-effort
Overprovision where?
Expensive
Converged Networks:
“Bursty” Traffic
3X to 5X not sufficient
Congestion still occurs 1 2 3 4
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
Packet Counts
Hours
Packets
Mean 5x 4x 3x 2x