S 6.75 Redundant communication links

Initiation responsibility: Head of IT Section, IT Security Management Team

Implementation responsibility: Administrator

Depending on the availability requirements, failure or non-availability of communication links could be extremely serious. This applies both to telephone connections and also to LAN or WAN connections. However, there are a large number of potential sources of failure so that it is often difficult to establish the exact cause.

As working environments are becoming more and more heavily networked these days, the failure of communications links can mean that important data and information cannot be exchanged. This can result in workflows being interrupted until the connection has been restored or alternative solutions have been found.

It is therefore sensible to hold alternative solutions ready for the different communication links (depending on their protection requirement).

Examples

• The telephone connection of a control centre should be guaranteed not only over the fixed network but also over mobile phone.

• As well as the normal Internet provider, a second provider should be used to guarantee connection of the e-mail server to the outside world.

• As well as the e-mail connection and/or in addition to a fax server, there should also be a fax machine available to cover the possibility of the network connection or the server going down.

It is not always necessary here to have another connection with the same bandwidth and the same quality requirements. In many cases it will be sufficient to be able to maintain limited IT operations in an emergency (see also Section 3.3 "Contingency Planning Concept").

Additional controls:

• Are there any alternative solutions for important communication links?

• Are the alternative solutions regularly adapted in line with technological developments?