H.323 vs. cops interworking

08/04/23 Saverio Niccolini Slide 1

VoIP Dynamic Resource Allocation in IP VoIP Dynamic Resource Allocation in IP DiffServ Domain:DiffServ Domain:

H.323 vs. COPS interworkingH.323 vs. COPS interworking

Stefano Giordano, Michele Mancino, Alessandro Martucci,Saverio Niccolini

Terena Networking Conference 2002

Limerick – Ireland

3 – 6 June


Outline

• Motivation & Targets

• QoS Provisioning: the scenario

• Dynamic Resource Allocation: a proposal

• Field Trial Description

• Interoperability Tests


Outline







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

Time of the day

AvailableBandwidthUserRequest

Mb

its

/Se

c

OverbookingUnderutilization

• Our goal is to provide the user with anAutomatic QoS Provisioning every time they need it


Outline







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


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)

trigger p

oint

• 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)


H.323 and COPS protocols

• 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

• H.323 is the more deployed (until now) multimedia conferencing protocol for packet-switched networks

COPS Glossary:

• PEP = Policy Enforcement Point• LPDP = Local Policy Decision Point• PDP = Policy Decision Point


Outline







DS BR

BB

A proposal for a DRA architecture

COPS Glossary: • PEP = Policy Enforcement Point• LPDP = Local Policy Decision Point• PDP = Policy Decision PointDiffServ Glossary• DS BR = DiffServ Border Router• BB = Bandwidth Broker


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

H.323 zone

GateKeeper (modified)

H.323 zone

GateKeeper (modified)

COPS ResponseCOPS Request DiffServ Router

configuration

Bandwidth Broker

DiffServ Region

Local or remote

decision?

Bi-directional configuration

Data traffic


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


Outline







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


Outline







Test results

Current Implementation report (signaling modes and H.323

procedures)

Interoperability tests performed

X = successfuly testedNO = test failureN.T. = Not testedN/A = Not Available


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


Questions ?

Technology

H.323 vs. cops interworking