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H.323 vs. cops interworking
1. Terena Networking Conference 2002
Limerick – Ireland
3 – 6 June
VoIP Dynamic Resource Allocation in IP
DiffServ Domain:
H.323 vs. COPS interworking
Stefano Giordano, Michele Mancino, Alessandro Martucci,
Saverio Niccolini
Slide 1
2. Outline
• Motivation & Targets
• QoS Provisioning: the scenario
• Dynamic Resource Allocation: a proposal
• Field Trial Description
• Interoperability Tests
Slide 2
3. Outline
• Motivation & Targets
• QoS Provisioning: the scenario
• Dynamic Resource Allocation: a proposal
• Field Trial Description
• Interoperability Tests
Slide 3
4. Motivation & Targets
• The current Internet architecture can not provide any QoS (Quality of Service)
• Increasing the available bandwidth with no strict control on data plane is not
enough since:
• it leads to higher costs
• it is a possible source of un-fairness
• There is the need of an interaction
between the control and the data plane
in order to provide the users with a
scalable/on-demand QoS
Available
• Our goal is to provide the
Bandwidth
user with an
Mbits/Sec
User
Request
Automatic QoS Provisioning
every time they need it
Underutilization Overbooking
Time of the day
Slide 4
5. Outline
• Motivation & Targets
• QoS Provisioning: the scenario
• Dynamic Resource Allocation: a proposal
• Field Trial Description
• Interoperability Tests
Slide 5
6. DiffServ architecture
• The QoS architecture object of our trials and demonstrations is the DiffServ
(Differentiated Services) architecture since it provides:
• scalability
• aggregation issues
• complexity pushed at the edge as in a pure Internet paradigm
• In our work the DiffServ is supposed to be the interconnecting architecture of
two or more VoIP administrative zones
Slide 6
7. QoS Provisioning: the scenario
• The trigger point is the DiffServ Border Router (DS BR) (intended to be the
default access gateway of the DiffServ domain) which is the device in charge to
ask access to the QoS network by means of asking permissions to the Bandwidth
Broker (BB)
• Our target is to dynamically automate the DiffServ mechanism in order to
achieve resource allocation extracting the needed information directly from the
signaling protocol (in this work we are focusing on the H.323 protocol)
t
poin
g er
t rig
Slide 7
8. H.323 and COPS protocols
• H.323 is the more deployed (until now) multimedia conferencing protocol for
packet-switched networks
• Although resource reservation mechanism are out of the scope of the H.323
itself there is the need to analyze the general methods and coordinations of such
mechanism with the H.323 protocol
• COPS (Common Open Policy Service) is a query and response protocol used to
exchange policy and to handle request/responses
COPS Glossary:
• PEP = Policy Enforcement Point
• LPDP = Local Policy Decision Point
• PDP = Policy Decision Point
Slide 8
9. Outline
• Motivation & Targets
• QoS Provisioning: the scenario
• Dynamic Resource Allocation: a proposal
• Field Trial Description
• Interoperability Tests
Slide 9
10. A proposal for a DRA architecture
DS BR COPS Glossary:
• PEP = Policy Enforcement Point
• LPDP = Local Policy Decision Point
• PDP = Policy Decision Point
BB DiffServ Glossary
• DS BR = DiffServ Border Router
• BB = Bandwidth Broker
Slide 10
11. H.323 – COPS interworking
• Both resource allocation model are supported in our work (outsourcing and
provisioning)
• A combination of the two models is chosen taking advantage from the dynamics of
the former and the scalablity of the latter
Local or remote
decision? Bandwidth Broker
COPS Response
COPS Request DiffServ Router
GateKeeper
configuration
(modified)
GateKeeper
(modified)
DiffServ Region
Bi-directional configuration H.323 zone
H.323 zone
Data traffic
Slide 11
12. Detaling the mechanism
A modified H.323 GK forwards
every H.323 message to the DS
BR (no matter of what H.323
signaling mode is chosen)
The DS BR is able to understand
the H.323 signaling and to trigger
a COPS request to the BB (a
combination of outsourcing and
combiantion model is chosen for
sake of scalability)
The BB react to the COPS
requests checking the
administrative issues and the
resource avalability
GKCTRL = GateKeeper ConTRol protocol (custom protocol used to exchange information with the
Gatekeeper)
IMR/IMD = Incoming Message Request/Decision (intended for administrative scope only)
RAR/RAD = Resource Allocation Request/Decision
Slide 12
13. Outline
• Motivation & Targets
• QoS Provisioning: the scenario
• Dynamic Resource Allocation: a proposal
• Field Trial Description
• Interoperability Tests
Slide 13
14. Field trial
• The field trial running at the University of Pisa is shown in the figure below
• Each “H.323 related “ software module is developed from scratch or modifying
the OpenH323 software
• The H.323 GKs are running on Linux PCs
• Each router (both border and core) is a Linux box router
• As regards as the DiffServ functionalities we used the Linux Traffic Control
• For testing the voice data traffic we used both H.323 software client
(NetMeeting, etc.) and H.323 hardware phones
Slide 14
15. Outline
• Motivation & Targets
• QoS Provisioning: the scenario
• Dynamic Resource Allocation: a proposal
• Field Trial Description
• Interoperability Tests
Slide 15
16. Test results
Current Implementation report
(signaling modes and H.323 procedures)
Interoperability tests performed
X = successfuly tested
NO = test failure
N.T. = Not tested
N/A = Not Available
Slide 16
17. Conclusions and ongoing works
• A VoIP Dynamic Resource allocation architecture for DiffServ has been
proposed where H.323 protocol triggers the queries to the DiffServ
domain
• The scalability issues where solved using a combination of the COPS
resource allocation model (outsourcing and configuration)
• The field trial was tested using different H.323 clients (both software
and hardware)
• The control plane was successfully tested and now is up and running
• The data plane is going to be tested with special attention to the QoS
issues and the quality perceived at user level
Slide 17
