a voice over ip quality monitoring architecture€¦ · fone@rnp service • only cisco gateways...
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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
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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
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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
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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
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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
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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
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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
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VQPlot
Application that reads and plots VQLog files
Together with a client that uses VQuality, like VQOpenPhone, it becomes a powerful analysis tool
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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
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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)
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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
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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
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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
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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