Dynamic-CBT and ChIPS – Router Support for Improved Multimedia Performance on the Internet Jae...

Dynamic-CBT and ChIPS – Router Support for Improved Multimedia

Performance on the Internet

Jae Chung and Mark Claypool

Computer Science DepartmentWorcester Polytechnic InstituteWorcester, Massachusetts, USA

http://perform.wpi.edu/

The Internet and Multimedia

Internet routers are best effort– No timing constraints– Packet loss, which indicates congestion

TCP– Completely reliable delivery through retransmission– Respond to loss as congestion

But … TCP often unsuitable for interactive multimedia– Full reliability not needed– Window-based rate fluctuations

Multimedia Using TCP

Multimedia Using UDP

Multimedia on the Internet

Multimedia often uses UDP– Avoid delay and jitter from retransmission– Rate-based– Unresponsive!

Router queue management goals– Congestion Control– Fairness

– Reduce Jitter

Router Queue Management

Drop Tail (FIFO)Drop Tail (FIFO)

Resource ReservationResource Reservation Active Queue MgmtActive Queue Mgmt

......(Floyd, Jacobson ‘95)

CBQCBQ ......(Floyd, Jacobson ‘93)

REDRED

Class-Based Threshold (CBT)


(Parris, Jeffay, Smith ‘99)

Bursty LossUnfairness

Outline

Introduction CBT D-CBT ChIPS Conclusion

CBT Design

Router Queue Management

Drop Tail (FIFO)Drop Tail (FIFO)

Resource ReservationResource Reservation

......

Active Queue MgmtActive Queue Mgmt

...... (Lin, Morris ‘97)

FREDFRED



(Floyd, Jacobson ‘95)

CBQCBQ(Floyd, Jacobson ‘93)

REDRED

(Parris, Jeffay, Smith ‘99)

ChIPSChIPS

Dynamic-CBTDynamic-CBT

D-CBT DesignResponsive MM

EnableThrsh

Evaluation in NS

Developed responsive multimedia application (for tagged UDP class)– AIMD Media Scaling (5 discrete rates)– “MPEG-1 like” transmission rates

Implemented and validated CBT

Implemented D-CBT and measured congestion time fairness– RED vs. CBT vs. D-CBT

Simulation (RED, CBT, D-CBT)

0 10 20 30

25 FTP-TCP

30 FTP-TCP

2 CBR-UDP(5Mbps each)

10 MM-UDP

s1

n1

s2

s66

s67

n2

r2

r2

r66

r67

25Mbps, 20ms

25Mbps, 5ms25Mbps, 5ms

n1-n2: q_size = 60

RED: max_th = 15 min_th = 5 qweight = 0.002 max_prb = 0.1

CBT: mmu_th = 2.9 udp_th = 0.6Second

RED: Class Average Per-Flow Throughput

537293 161

851 720 601

45034681

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 ~ 10 Sec 10 ~ 20 Sec 20 ~ 30 Sec

Kbp

s

TCP

TAG_UDP

UTAG_UDP

Fairness: RED

Fairness: CBT

CBT: Class Average Per-Flow Throughput

587 613

305

760 739657624

318

0

100

200

300

400

500

600

700

800

900

1000

0 ~ 10 Sec 10 ~ 20 Sec 20 ~ 30 Sec

Kbp

s

TCP

TAG_UDP

UTAG_UDP

Fairness: D-CBT

D-CBT: Class Average Per-Flow Throughput

622659

356

653 660

378

637

313

0

100

200

300

400

500

600

700

800

900

1000

0 ~ 10 Sec 10 ~ 20 Sec 20 ~ 30 Sec

Kbp

s

TCP

TAG_UDP

UTAG_UDP

Outline

Introduction CBT and D-CBT

– Design – Evaluation

ChIPS – Design– Evaluation

Conclusion

Cut-In Packet Scheduling (ChIPS) Design

ChIPS Evaluation - Jitter

MM_APP Frame Delay under Basic D-CBT

30

32

34

36

38

40

42

44

0 5 10 15 20 25 30

Simulation Time (Seconds)

Del

ay (m

illis

econ

ds)

D-CBT

MM_APP Frame Delay under D-CBT with ChIPS

30

32

34

36

38

40

42

44

0 5 10 15 20 25 30

Simulation Time (Seconds)D

elay

(mill

isec

onds

)

D-CBT-ChIPS

ChIPS Evaluation - Fairness

TCP Packets Delivered

TCP Packet Drop Rate

TCP Throughput

D-CBT 66,648 pkts 4.46 % 17,773 Kbps

D-CBT w/ ChIPS

66,386 pkts 4.44 % 17,703 Kbps

D-CBT: Class Average Per-Flow Throughput

622659

356

653 660

378

637

313

0

100

200

300

400

500

600

700

800

900

1000

0 ~ 10 Sec 10 ~ 20 Sec 20 ~ 30 Sec

Kbp

s

TCP

TAG_UDP

UTAG_UDP

D-CBT with ChIPS: Class Average Per-Flow Throughput

608666

355

673 664

384

563

297

0

100

200

300

400

500

600

700

800

900

1000

0 ~ 10 Sec 10 ~ 20 Sec 20 ~ 30 Sec

Kbp

s

TCP

TAG_UDP

UTAG_UDP

Conclusion

D-CBT– Protect responsive flows from unresponsive– Class-based consideration– Adaptive to mix of flows

ChIPS– Reduce multimedia jitter during congestion

Future Work

Active Flow Counting (Overhead)

– For every incoming packet, update flow info

• Hash Table - O(1)

– Every ms, delete old flows

• Hash Table - O(n)

Measure Overhead– Processing Time and Memory Usage

Future Work

How many different classes are needed?– Example

• 1 class is RED

• 1 class per flow is FRED

– Overhead per class

Effects of D-CBT and ChIPS on Perceptual Quality

Dynamic-CBT and ChIPS – Router Support for Improved Multimedia Performance on the Internet Jae...

Documents

Transcript of Dynamic-CBT and ChIPS – Router Support for Improved Multimedia Performance on the Internet Jae...