TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF TECHNOLOGY An Implementation

TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF TECHNOLOGY An Implementation of the Server Cache Synchronization Protocol (SCSP) Jose Costa Requena Raimo Kantola jose@tct. hut. fi Raimo. Kantola@hut. fi SPIE Conference Boston, September 1999

TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF TECHNOLOGY Contents 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 SPIE'99 2

TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF TECHNOLOGY Problem Definition 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. Subscriber & User Database Subscription & Service Profile Management Service Provider Billing User Data Usage Management Usage Network Operator SPIE'99 Billing Value Added Service Provider Usage 3

TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF TECHNOLOGY Problem Definition 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 SPIE'99 4

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 IP Telephony Signaling server SPIE'99 5

TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF TECHNOLOGY SCSP Specifications 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. SPIE'99 6

TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF TECHNOLOGY SCSP Specifications The SCSP is based on three sub-protocols. Hello Protocol is used to know whether the connection between servers is available. Cache State Update performs a flooding mechanism where any new information in one of the servers is dynamically updated in all other servers. Cache Alignment Protocol allows a server to synchronise its entire data: exchanging short summaries from the entire database, comparing of summaries to know the newest data, requesting the entire information to the server which provided the summary with the newest data SPIE'99 7

SCSP Modules TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF TECHNOLOGY SCSP Algorithms module User Interface Databases module DATA BASES User Interface SCSP OBJECT TABLES Communications module (TCP/IP) Auto Configuration System Object Tables User Interface Auto Config System Auto Config. System TCP/IP SCSP TCP/IP SPIE'99 DATA BASES OBJECT TABLES 8

Modules Interaction TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF TECHNOLOGY Server i Hello Packets HFSM Server i+1 Cache Alignment packets CAFSM CLIENT USE SCSP PRIMITIVES Cache State Update packets CSU SCSP t t t SPIE'99 9

TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF TECHNOLOGY Applications SCSP for data replication in the GLP Implementation LS GLP ITAD 1 SCSP database ITAD 3 GLP LS SCSP database ITAD 2 GLP LS SCSP database GLP: Gateway Location Protocol LS: Location Server ITAD: Internet Telephony Administrative Domain SPIE'99 10

TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF TECHNOLOGY Applications SCSP as the common element for a global GLP Implementation and interoperability between GSTN and IP GLP Database SCSP GATEKEEPER SS 7 PSTN GATEKEEPER SPIE'99 GLP Database SCSP 11

Applications TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF TECHNOLOGY SCSP as basic component to allow interoperability between IN databases and user information directories in IP Databases SCSP GLP Database SCSP SCP GATEKEEPER IP SS 7 PSTN or GSM SPIE'99 12

Conclusions TEKNILLINEN KORKEAKOULU HELSINKI UNIVERSITY OF TECHNOLOGY 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. NEXT. . . SCSP could become a key component of the emerging directory enabled networks. SPIE'99 We continue working on future applications of the SCSP as the generic component to allow interoperability between IN and IP services. 13