In order to cover needs of regular maintenance, and integration of new services, techniques, settings, parameters, protocols, etc. in the network infrastructure (routers, switches, servers and storage equipment), actions may be required which may result to instabilities or other unexpected effects in the network. For this reason and in order to make certain that any malfunctions in the network shall occur in a controlled manner, one or more trial and maintenance windows are defined.
All major changes, upgrades, activations of new techniques or features, etc. shall take place during any of the above mentioned, two types of windows. If, while using a window for upgrading or activating new techniques, etc. problems occur and the allowed time period elapses, a return to the previously known, stable situation shall be initiated.
The first type of window is the maintenance window. The duration of a maintenance window shall be sufficient to allow to make changes in operating systems, features activations, etc. on individual systems or network sections. The use of the maintenance window is recommended in cases where:
- The disruption of the network or the services operation by management act, is certain or highly likely.
- The chances for a problem or an instability to result from a management act, are considered to be poor.
- The time allowed to verify whether the management act is successful, is short (some minutes).
- It is certain or highly likely that a transition to the previous stable situation should be required, a new disruption of the network or services operation, shall be necessary.
The maintenance and trial windows are as follows:
- Monday afternoon, 18.00-20.00
- Wednesday morning, 08: 00-10: 00
- Wednesday afternoon, 18.00-20.00
The trial windows are used to perform scheduled works that require disruption of GRNET services. Such works, are scheduled, when possible, in the afternoon windows that the use of GRNET network and services are lower. In the morning maintenance window, works related to the Student DSL (DIODOS program), GR-IX and works that require physical access to GRNET nodes that are co-located in OTE buildings where there is no 24-hour access, shall be usually scheduled. To ensure high availability of the GRNET network and services, it is not allowed to schedule works in two different Maintenance Windows within the same week, if such works may cause significant interruption or disruption of services received by at least one GRNET organization. In the event that the maintenance or trial window coincides with a public holiday or day that for other reasons (force majeure, etc.) it is impossible to perform the necessary management actions, GRNET may re-schedule such maintenance window. Moreover, in exceptional cases, the duration of Maintenance Windows may be extended in order to perform works whose expected duration exceeds the size of the Window. In both cases, GRNET organizations are properly informed by the Helpdesk Department. It is noted that in order to deal with emergencies and to ensure the stability of the network and services, works outside Maintenance Windows can be performed.
