Link states: the SONET state dictionary
The SONET State Dictionary groups states and indicators that are used most often to display transport links with the protection process. Such link state graphics are useful only in applications in which the end user must be informed about link states and protection switching information (as in a fiber transport network, for example).
This state system should not always be used, for the following reasons:
The states are not necessarily adapted to the specific application case. For example, you may want to ignore the issue regarding the protection facility.
In some network representation cases, you may decide not to use these graphics, since they might interfere with other managed object state graphics.
Primary states
The SONET State Dictionary includes a certain number of primary states involving changes in the drawing of the link base.
Although this set of states is independent of OSI or Bellcore standards, it shares the following common subset with the following three main states:
Disabled: the facility is Out Of Service (OOS).
Inactive: the working facility is in service, carrying No Traffic (NT).
Active: the working facility is in service, Carrying Traffic (CT).
The other states determine the state of the link in relation to the usage and state of the protection facility:
Active and Protecting: the working facility is carrying traffic and the protection facility is enabled.
Troubled and Protected: the working facility is troubled (failure conditions are reported) and the protection facility is active (the failure conditions triggered the protection switch).
Troubled and Unprotected: the working facility is troubled and the protection facility is unable to protect.
Secondary states
The SONET State Dictionary includes a number of secondary states, or
protection switch request indicators, that deal with the protection process. These states can be applied either at both link ends or at one link end only. Programming such states is explained in
Setting link states.
You can extend the list of the SONET secondary states to take into account your own state definitions and their associated icons. More details about extensions are provided in
Customizing the SONET state system.
The SONET primary and secondary states are described individually in the following reference tables:
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