A Voice over IP Quality

Monitoring Architecture8th International Conference on

Management of Multimedia Networks and Services

MMNS 2005 – MANWEEK 2005

Barcelona, October 2005

Leandro Caetano Gonçalves Lustosa, Ms.C.

Núcleo de Computação Eletrônica -NCE

Universidade Federal do Rio de Janeiro - UFRJ

fone@RNP Service

• Only Cisco gateways generates CDR with quality indicators

• Environment where the VoIP quality monitoring has been applied

SIP Environment

Proxy SIP

SIP/H.323

Gateway

H.323 Environment

Gatekeeper H.323

H.323 IP Phone

(Software)

H.323 IP Phone

(Software)

SIP IP Phone(Software)

VoIP GatewayPABX

Institution B

SIP Environment

Proxy SIP

SIP/H.323Gateway

H.323 Environment

Gatekeeper H.323PABX

H.323 IP Phone

(Software)

SIP IP Phone

(Software)

VoIP Gateway

SIP IP Phone

(Software)

Institution A

RADIUSLDAP

RADIUSLDAP

VoIP Quality monitoring solutions

• Cryptography may block call

analysis

• Point-to-point voice traffic

may force packets to be routed

away from the probes

• Real calls are not analyzed

• Statistics may not reflect the

real network impact on voice

calls

• Quality of calls between IP

phones is not taking in account

Drawbacks

BROOM e HOLLIER

and several commercial

solutions

Passive monitoring

HUANG, CHAO e LIUSimulated calls among

distributed SNMP agents

CESNET and ECASCollection of gateways

CDRs

ExamplesMethodology

Voice over IP quality monitoring architecture

• Methodology

– CDRs are collected directly from IP phones and voice

gateways

– A new CDR format specification (Voice Quality CDR)

• Specific for voice quality monitoring

• Advantages

– More extensive and able to evaluate

• All real calls

• Cryptographic calls

• Point-to-point calls

Implementation

• Library for call quality evaluation and VQCDR generation (VQuality Library)

• IP phones and voice gateways incorporating VQuality

• Collection, authentication and storing of VQCDR

– Central entity (VQCDR Server)

Authentication

database

Storare

database

Voice Quality CDR (VQCDR)

• Call identifiers

– VoIP signaling protocol, codec, cally user, called user, etc…

• Call Quality indicators

– Delay Impairment, Equipment Impairment, loss rate, jitter buffer discard

rate, R-Factor, MOS, etc.

• Start time and call duration

• Optional fields

– Specific application information

– Voice Quality Log (VQLog)

• Quality history (call quality variation over time)

• Use of TCP/port 80 by default

– Reliable VQCDR transfer and facility for operation behind firewalls

Modified H.323 clients

• VQOpenPhone for Windows environments• VQMeeting for Unix environments• H.323 terminals based on OpenH323 library

– The RTT measurement mechanism of RTP/RTCP stack had to be implemented

• At the and of the call, clients evaluate the received voice quality, send the VQCDR and show the related MOS on their status panel

VQPlot

Application that reads and plots VQLog files

Together with a client that uses VQuality, like VQOpenPhone, it becomes a powerful analysis tool

VQuality CDR Server (VQCDR Server)

Collector Module (CM): in charge of collecting and interpreting received VQCDR, and activation of AM and SM modules

Authenticator Module (AM): in charge of VQCDR validation

Storage Module (SM): in charge of storing received VQCDR in a database

CollectorModule

AuthenticatorModule

StorageModule

VQCDR Server

GnuGK AM and RADIUS SM

• GnuGK AM

– Specific for Gatekeeper H.323 GnuGK

– Uses GnuGK remote port management for validating VQCDR originator

• RADIUS SM

– Specific for RADIUS

– However, RADIUS permits the interface with several SQL databases

– Use VSAs (Vendor Specific Attributes) to specify VQCDR fields (UFRJ –

21715)

Visualization Environment

• All CDRs generated are sent to a RADIUS server and storied in a SQL server

• These CDRs are consolidated in one single record and statistical graphics and

reports can be visualized on a Web interface

VoIP monitoring architecture summary

GnuGK Authenticator

Module (GnuGk AM)

(RadiusSM)

RadiusStorageModule

(CM)ColectorModule

VQCDR Server

H.323 GatekeeperGnuGK

Radius Server

Authentication

Storing

SQL Server

Sto

ring

4

7

PQR S

*

CISCO IP PHONE

790 2 SERIES

1 2

A B C

3

D E

F

4 5

J K L

6

M N OG H I

7 8

T U V

9

W X Y ZP Q R S

* 0 #

VQ

CD

R

Ge

nera

tio

n

IP Telephone with

VQuality

Web Server

An IP Telephone integrated with

VQuality evaluates

the call quality and

sends a VQCDR to the VQCDR Server

1

The CM

collects the

VQCDR and

activates the AM

2

The AM authenticates the VQCDR

and activates the SM if it is valid

3

The AM access the GnuGK to

validate the

VQCDR

4

The Radius Server receives the

VQCDR and

accesses the SQL

Server to store the VQCDR

information in a

database6

Call quality statistics are

presented on a web based interface7

If the VQCDR is valid, the SM

access the

Radius Server

to store the VQCDR

5

Conclusions

• A new VoIP quality monitoring architecture was presented and implemented

• A new specific voice quality CDR (VQCDR) format was proposed

• A library for objective voice quality evaluation was presented (VQuality)

• Architecture validation

– Implementation of VQCDR Server

– Implementation of VoIP clients with VQCDR support

• VQOpenPhone (based on OpenPhone)

• VQMeeting (based on Netmeeting )

– VQPlot

• VQLog file analysis

– It has been successfully applied in the RNP Brazilian research VoIPinitiative

Future work

• Integration of VQuality into SIP clients and Asterisk

• Development of a specific AM for SIP SER

• Analysis of the database fed by the fone@RNP service

– Analysis of voice traffic in RNP network backbone

– Validation and improvement of QoS infrastructure

• Development of automatic call simulator and measurement tool

– Call capacity determination

– Study of QoS policies for voice traffic

– Use in wired and wireless environments

• Incorporation of VQuality to Network Simulator (NS2)

– Design and evaluation of complex VoIP systems