Ist-muse.org On the Enhancement of QoE for IPTV Services through Knowledge Plane Development Bart De Vleeschauwer Wim Van de Meerssche Pieter Simoens Filip

ist-muse.org

On the Enhancement of QoE for IPTV Services through Knowledge Plane Development

Bart De VleeschauwerWim Van de MeersschePieter SimoensFilip De TurckBart DhoedtPiet Demeester

Edith Gilon

Kris Struyve

Tom Van Caenegem

BB Europe 14.12.2006 — 2 ist-muse.org

Overview

> Access network challenges

> Monitoring Plane & Knowledge Plane

> Monitoring in the home network


Access Network Overview

Service Providers

Service Edge

Access Node

Residential

Gateway

End Device

User

Access Network Home Network


Services & Challenge

> Classic best-effort internet services:

• Web Surfing, E-mail, File Transfer, …

> New services:

• VOIP, Broadcast IPTV, Video on Demand, Gaming• Higher Requirements:

– Interactivity, Media quality, Zapping Time, Setup Time, Synced Sound, Artifact-free Video

> Need for guaranteed Quality of Experience= how the user experiences the service• Influenced by network jitter, delay and loss

How can we detect & automatically solve QoE degradation?


Overview





Monitor Plane

MP/KP: Architecture

Knowledge PlaneQoE decrease detectedroot cause analysis

Monitoring data sources

restorative action


Monitor Plane

•Logical layer containing all monitoring tools:

•SNMP:

• Read & write device parameters

• Set traps

• IPFIX (or netflow):

• Flow statistics

• TR-069

• Residential gateway configuration & monitoring

• …


Knowledge Plane

Solution Execution

Monitoring Plane

Data Reduction

Knowledge plane Overview

Active: e.g. generate additional ICMP ping requests

Passive: e.g. additional threshold in RMON MIB

Anomaly Detection

Diagnosis and Solution

Additional queries over available data

Initialize new anomaly detection modules

Additional info might be needed for accurate fault recovery

Initiate new monitor probes

Anomaly is detected

e.g. FEC, interleaving, local retransmission, device reconfiguration, warn end-user or network management, …

Solve Problem

Continuous monitoring


Monitor Plane

MP/KP: Example

Knowledge PlaneQoE decrease detectedroot cause analysis restorative action

Loss

Detected

ADSL-line

Statistics:

loss detected

Loss in

Home

Network

Add FEC to stream

Cause known: ADSL-line loss


Overview





Home Network Monitoring

How to monitor?• Limited or no knowledge & control of end-devices

> Active monitoring

> Passive monitoring

Loss, RTT and

Jitter monitoring

From the Access Node

?


Active Monitoring

> Dedicated software• Assumes control of end-devices and end-device software by

access network

> ICMP-based• Each IP device should support “ping”• Can measure RTT, jitter and loss• Problem:

– Firewall– Might be handled differently than other traffic– Large Loss detection overhead!

– To detect a packet loss ratio p, you need 10/p packets

> Active monitoring isn’t very useful


Passive Monitoring

> From in the access network, monitor packets from and to the home network

> Use service specific algorithms to derive home network parameters

> Use cases:• Broadcast TV using RTP/RTCP • VoD using TCP


RTP/RTCP monitoring

> Overview:• RTP/RTCP basics• Jitter Monitoring• Loss Monitoring

RTP

RTCP Sender Reports

RTCP Receiver Reports


RTP/RTCP

> RFC 3550: RTP: A Transport Protocol for Real-Time Applications

> Two protocols• RTP protocol for data packets• RTCP protocol for control traffic

> RTP packets contain data• Sequence number• Timestamps (Sampling instant of first octet in the RTP data

packet)

> RTCP packets contain control & feedback information


RTCP Messages

> SDES, source description items

> BYE, end of participation

> APP, application specific

> SR, Sender Report

> RR, Receiver Report

Report Block


RTP/RTCP loss estimation

> Receiver report:

> Same calculations can be done on AN,by looking at RTP stream

# Expected - # Received

Fraction lost since last RR

Loss


Access node home network loss detection

Receiver Reports (loss=A)

RTP Monitoring on AN (loss=B)

Calculate: A - B

Access Network Home Network


RTP/RTCP interarrival Jitter estimation

> Interarrival jitter: variance in interarrival timeServer

Access Node (AN)

Sj

time

> End-to-end jitter is reported in RR

> Do analogous calculations on RTP at AN to determine Server – AN jitter

> Compare end-to-end jitter (RR) and Server-AN jitter

Sk

Aj Ak

End-Device Rj Rk

Si

Ai

Ri


TCP monitoring

> Overview:• TCP basics• RTT & Jitter Monitoring• Loss Monitoring• Our algorithm: ANTMA

TCP


TCP: Basics

DP 1Sender Receiver

Monitoring Point

1 A1

ACK 1


TCP: Loss

DP 1DP 1

Time-out!

Sender ReceiverMonitoring Point

1 A11

ACK 1


1

TCP: Flights

DP 1DP 2

ACK 1

Sender ReceiverMonitoring Point

A12

ACK 2

A2


TCP Middle Monitoring: RTT & Jitter in home network

> RTT is time between seeing a data packet, and seeing its matching ACK

> “RTT Jitter” can be derived from RTT

> Finding matching ACK is hard when loss & jitter occur:

1 2 3 4 A1 A1 2 3 4 A1 A4 A4 A4

ACK 1

DP 1

Need smart matching for jitter detection!


TCP Middle Monitoring: Loss in Home Network

> Counting retransmissions• Unreliable, as jitter can cause retransmissions• Tests on the internet show difference with loss

can be very high

> “Smart” counting retransmissions• Assume multiple losses in row are jitter, and

ignore them• Bursty loss is seen as jitter!


TCP Middle Monitoring: ANTMA

> ANTMA = “Access Network TCP Monitoring Algorithm”

> What?• Loss, RTT & Jitter estimations• Measure each TCP connection separately• Monitor only home network part of connection

> How?• Passive monitoring of packets on AN (or RGW)• History is evaluated by various rules• Packets are matched with their ACK


TCP Middle Monitoring: ANTMA Example

MP

ACK 1

DP 1DP 2DP 3DP 4DP 5DP 6

ACK 2ACK 3ACK 3

1 2 3 A1 A2 A3 4 5 6 A3 A3ACK 3

History: 1 2 3 A1

Can match: 1,3

A2 A3

2 3

4 5 6 A3 A3

5,6 6

LOST


Conclusion

> Monitoring Plane• Monitoring in Acces Network• Monitoring in Home Network

– RTP/RTCP– TCP

> Knowledge Plane• Detect & Solve QoE degradations


Questions?

Documents

Ist-muse.org On the Enhancement of QoE for IPTV Services through Knowledge Plane Development Bart De Vleeschauwer Wim Van de Meerssche Pieter Simoens Filip