# Commission Decision of 16 March 2007 laying down the network requirements for the Schengen Information System II (1st pillar) (notified under document number C(2007) 845) (Only the Bulgarian, Czech, Dutch, German, Estonian, Finnish, French, Greek, Hungarian, Italian, Latvian, Lithuanian, Maltese, Polish, Portuguese, Romanian, Slovak, Slovenian, Spanish, and Swedish text is authentic) (2007/170/EC), Division 4.1: Network layout

Extent: E+W+S+N.I.

The SIS II architecture makes use of centralised services, which are accessible from the different Member States. For resiliency purposes these centralised services are duplicated to two different locations namely Strasbourg in France and St Johann im Pongau in Austria, respectively the CS-SIS, CU and backup CS-SIS, BCU.
The central units, main and backup, must be accessible from the different Member States. The participating countries may have multiple network access points, a LNI and a BLNI, to interconnect their National System to the central services.
Apart from the main connectivity towards the central services, the Communication Infrastructure must also support bilateral supplementary information exchange between the Sirene offices of the different Member States.

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Source: https://www.legislation.gov.uk/eudn/2007/170/annex/division/4/division/4.1 (the official version)
Page: https://openlegislation.uk/eu-decision-2007-170/annex/division-4/division-4.1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.