An Implementation of the Server Cache Synchronization Protocol (SCSP)

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TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF
TECHNOLOGY
An Implementation of the Server Cache
Synchronization Protocol (SCSP)
Jose Costa Requena Raimo Kantola
jose_at_tct.hut.fi Raimo.Kantola_at_hut.fi
SPIE Conference Boston, September 1999
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Contents
TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF
TECHNOLOGY
Problem Definition
SCSP as Solution
Protocol Specifications (RFC 2334) Basic Features
Our Implementation
Modules in the implementation Interaction between
modules
Applications
GLP Implementation
GLP Interoperability IP GSTN
Conclusions and Future Work
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Problem Definition
TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF
TECHNOLOGY
Directories are key component for IP based
communications networks.
The large amount of data is stored in distributed
databases the changes must be updated among the
entities related to the same service.
Subscription Service Profile Management
Service Provider
Billing
Value Added Service Provider
User Data Management
Billing
Usage
Usage
Network Operator
Usage
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Problem Definition
TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF
TECHNOLOGY
Directories hold static and dynamic information
about the users and the services themselves.
Services need to interoperate across
administrative boundaries and
directories need to be accessible from
everywhere.
IP Telephony Signaling server
Zone B Database
Zone B
Zone A Database
Zone A
IP Telephony Signaling server
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Our Solution
TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF
TECHNOLOGY
The SCSP solves the problem of data
replication/synchronisation in a group of
distributed servers without heavy overheads like
in the actual tight consistency techniques.
IP Telephony Signaling server
SCSP
SCSP
IP Telephony Signaling server
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SCSP Specifications
TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF
TECHNOLOGY
The SCSP elements
Server Group (SG). Is the group of servers to
be synchronised. Local Server (LS). Is the
server under scrutiny. Direct Connected Server
(DCS). Is the server directly connected to LS.
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TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF
TECHNOLOGY
SCSP Specifications
The SCSP is based on three sub-protocols.

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TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF
TECHNOLOGY
SCSP Modules
SCSP Algorithms module Communications module
(TCP/IP) User Interface Auto
Configuration System Databases module Object
Tables
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Modules Interaction
TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF
TECHNOLOGY
Server i
Server i1
Hello Packets
Cache Alignment packets
CLIENT USE SCSP PRIMITIVES
CLIENT USE SCSP PRIMITIVES
Cache State Update packets
t
t
t
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Applications
TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF
TECHNOLOGY
SCSP for data replication in the GLP
Implementation
ITAD 3
LS
ITAD 1
GLP
LS
database
ITAD 2
LS
GLP Gateway Location Protocol LS Location
Server ITAD Internet Telephony Administrative
Domain
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Applications
TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF
TECHNOLOGY
SCSP as the common element for a global GLP
Implementation and interoperability between
GSTN and IP
GLP Database SCSP
SS7 PSTN
GLP Database SCSP
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Applications
TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF
TECHNOLOGY
SCSP as basic component to allow interoperability
between IN databases and user information
directories in IP
GLP Database SCSP
Databases SCSP
GLP Database SCSP
SCP
IP
SS7 PSTN or GSM
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TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF
TECHNOLOGY
Conclusions
NOWADAYS ...
SCSP has been developed in a modular way to
provide a generic service to be used by other
systems for their data replication.
SCSP follows a building-block design to permit
its integration with other mechanisms to achieve
an efficient overall behaviour.
In terms of overall positioning we consider the
SCSP as a key tool for the future services
globalisation.
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