Jack Douglass, Spirent Chair TIA TR30.3 August 2004 TR30.3 TR30.3/04-08-018

Analyze Assure Accelerate

Network Model for Evaluating Multimedia Transmission Performance Over Internet Protocol

PN-3-0062 Will become TIA/EIA-921

Jack Douglass, Spirent

Chair TIA TR30.3

August 2004

TR30.3 TR30.3/04-08-018

[email protected]


TR30.3 Network Model Standards

• TIA/EIA 496A-1989: Interface Between Data Circuit Terminating Equipment (DCE) and the Public Switched Telephone Network

– Included Network Model for Evaluating Modem Performance

• TIA/EIA TSB 37A-1994: Telephone Network Transmission Model for Evaluating Analog Modem Performance, which became ITU-T Recommendation V.56bis-1995

• EIA/TIA TSB 38-1994: Test Procedures for Evaluation of 2-Wire 4 Kilohertz Voice Band Duplex Modems, which became ITU-T Recommendation V.56ter-1996

• ANSI/TIA/EIA 3700-1999: Telephone Network Transmission Model for Evaluating Analog Modem Performance

• ANSI/TIA/EIA 793 -2000: North American Telephone Network Transmission Model for Evaluating Analog Client and Digitally Connected Server Modems

• ANSI/TIA 876 – 2002: North American Network Access Transmission Model for Evaluating xDSL Modem Performance


Purpose of Presentation

• Establish a formal liaison between TR30.3 and appropriate committees to help develop TIA-921 (PN-3-0062), Network Model for Evaluating Multimedia Transmission Performance Over Internet Protocol Other Liaisons Activities– TR41.4

– ITU-T SG12 -- Approved as Question M/12

– ITU-T SG11

– ITU-T SG13

– ITU-T SG15 Q7

– ITU-T SG16 Q11, Q14 (QF)

– IETF

– Etc.

• Invite committee members to TR30.3 meetings to work on IP Network Model– IP Network Statistics

– Network Architecture

– Test Scenarios


Network Model for Evaluating Multimedia Transmission Performance – TIA-921 (PN-3-0062)


Parameters and Impairments that Affect Voice Quality

• Network Architecture

• Types of Access Links

• QoS controlled Edge Routing

• Voice coding algorithm

• A/D and D/A Conversion

• MTU Size

• Signaling protocol mismatches

• Network faults

• Link Failure

• Time Drift

• Route Flapping

• Echo

• Out of order packets

• Noise – Circuit and External

• Packet Loss (Frame Loss)

• One Way Delay (Latency)

• Variable Delays (Jitter)

• Background Traffic (Congestion, Bandwidth, Utilization, Network Load, Load Sharing)

ITU G.113 defines the transmission impairments and their impact on voice quality


IP Network Model

Core IP NetworkLAN A

Local AccessB

1000BaseX* 100BaseT Switch100BaseT Hub10BaseT* WLAN (~4 Mbit/s)----------------------Occupancy levelPacket loss

64 kbit/s*128 kbit/s256 kbit/s*384 kbit/s512 kbit/s*768 kbit/s

*T1 (1.536 kbit/s)E1 (1.920 kbit/s)E3 (34 Mbit/s)*T3 (44 Mbit/s)

ADSL (~256 kbit/s)*Cable (~256 kbit/s)Fiber (1-10 Gbit/s)

--------------------Occupancy levelQoS edge router

LAN B

Route flappingOne-way delay

JitterPacket loss

DestinationDevice B

Local AccessA

64 kbit/s*128 kbit/s256 kbit/s*384 kbit/s512 kbit/s*768 kbit/s

*T1 (1.536 kbit/s)E1 (1.920 kbit/s)E3 (34 Mbit/s)*T3 (44 Mbit/s)

ADSL (~2 Mbit/s)*Cable (~3 Mbit/s)Fiber (1-10 Gbit/s)

--------------------Occupancy levelQoS edge router

SourceDevice A

* Case used in impairment tables

1000BaseX* 100BaseT Switch100BaseT Hub10BaseT* WLAN (~4 Mbit/s)----------------------Occupancy levelPacket loss


TIA-921 IP Network Impairment Emulator

Jitter, Latency, Burst Loss, Gap Loss

Packet Loss, Out-of-Order Packets

Route Flapping, Link Failure

Scenario Based Time Varying

IP Network Impairments

IP Network Impairment Emulator

Types of DUTsIP PhonesPOTS over IPMedia Gateways MGCUser AgentsCall Agents Media ServersVideo Gatekeepers Application Servers Edge Routers GatewaysModemsFax


Testing with Fixed Levels of IP Impairments

• Impairments Placed in series between Tester and network equipment under test

• Test Examples:

– Evaluate jitter buffer and packet loss concealment algorithms

– Ability of equipment to handle impairments

Impairment Type Units Range

Jitter ms +/- 75

One Way Latency ms 50 to 150

Sequential Packet Loss

#sequential packets losses

0 to 3

Rate of Sequential Loss

sec-1 < 10-3*

Random Packet Loss % 0 to 2

Out of Sequence Packets

% 0 to 10-1**

Real Network Impairments Vary Over Time


TIA-921 – Statistically Based IP Network 500 Impairment Conditions (ICs) per SLA

• Each Impairment Condition is assigned a Likely-hood of Occurrence (LOO) based on real IP Network Statistics, Network Architecture, Classes of Service

• The goal is to have approximately 500 test combinations so that an automated run of the test suite completes in less than a day.

IC1

Prob

(LOO X%)

IC2

Prob

(LOO X%)

IC500

Prob

(LOO X%)

Time (s)

Del

ay (

ms)

Del

ay (

ms)

Del

ay (

ms)


TIA-921 Test Profiles Based on QoS Classes

Test Profiles QoS Class(Y.1541)

Applications (Examples) Node Mechanisms Network Techniques

A(VoIP, MoIP, FoIP, ToIP)

0 Real-Time, loss sensitive, Jitter sensitive, high interaction (VoIP, VTC)

Strict QoS. Guaranteed no over subscription on links.

Constrained Routing and Distance

B(VoIP, MoIP, FoIP, ToIP)

1 Real-Time, Jitter sensitive, interactive (VoIP, VTC).

Separate Queue with preferential servicing, Traffic grooming

Less constrained Routing and Distances

C(FoIP only)

2 Transaction Data, Highly Interactive (Signaling)

Separate Queue, Drop priority

Constrained Routing and Distance

3 Transaction Data, Interactive Less constrained Routing and Distances

4 Low Loss Only (Short Transactions, Bulk Data, Video Streaming)

Long Queue, Drop priority Any route/path

5 Traditional Applications of Default IP Networks

Separate Queue (lowest priority)

Any route/path

• Statistically based models can be created for different QoS Classes


TIA-921 Test Profiles Based on QoS (Y.1541) Classes


Jitter ms +/- 50


Sequential Packet Loss #sequential packets

Random loss only

Rate of Sequential Loss sec-1

Random Packet Loss % 0 to 10-3*

Out of Sequence Packets % 0 to 10-1**


Jitter ms +/- 300



0 to 500

Rate of Sequential Loss sec-1 < 10-1*


Out of Sequence Packets % 0 to 10


Jitter ms +/- 75



0 to 3

Rate of Sequential Loss sec-1 < 10-3*


Out of Sequence Packets % 0 to 10-1**

Service Test profile C500 Impairment Combinations

Unmanaged Network

Service Test profile B500 Impairment Combinations

Managed Network

Service Test profile A500 Impairment Combinations

Well Managed Network

Different test profiles for different Service Level Agreements (SLAs)


TIA-921Example Impairment Combination Table

•Approximately 1500 test Scenarios •Run each Impairment Combination against rates

Test Scenario Conditions(Impairment Combination – IC)

IP Impairments Caused by Test Conditions (Impairment Combination – IC)


TIA-921 – Example of Network Model Coverage (NMC) Curve

Parameter X Vs Network Model Coverage Percentage

0

0 10 20 30 40 50 60 70 80 90 100

Percentage of Network Coverage

Device ADevice BDevice C

Qo

S,

PE

SQ

, P

SQ

M,

MO

S,

Th

rou

gh

pu

t, C

on

ne

ct R

ate

, e

tc.

Test Results from 500 Impairment Combinations


Network Statistics/Characteristics Required to Validate IP Network Model

Home

Egress LOO %

128 20

256 80

Ingress

128 20

768 35

3000 45

LAN

4 60

10 40

Business

Access LOO %

1536 75

44000 25

LAN

4 35

100 50

1000 15

Likelihood of Occurrence of Business Data RatesLikelihood of Occurrence of

Home Data Rates

Other Statistics/Characteristics

•Typical Impairment levels for SLAs

•Usage of QOS Edge Routing

•Route Flapping

•One Way Delay

•Packet loss

•Occupancy Level (Background Traffic)

•Validation of IP Impairment Characteristics (Algorithms)

Who are the contacts in the service providers, operating companies, network equipment manufacturers that can provide this information?

• Similar network statistics were provided for the other TR30.3 network models anonymously by service providers, operating companies and network equipment manufacturers


TIA-921 Target Audience for Network Model

• Operating Companies

• Service Providers

• Manufacturers

• Design Engineers

• Test houses

• Magazines and product reviewers

Documents

Jack Douglass, Spirent Chair TIA TR30.3 August 2004 TR30.3 TR30.3/04-08-018