Configuring a Synchronization Priority List

Before connecting to a network the IMG 1010 or IMG 1004 must be synchronized to a T1/E1 loop timing source such as a T1 or E1 DS-1. The IMG will allow up to four different clock sources to be connected to various inputs on the rear of the unit. Within the Clientview application, an object labeled Timing Synchronization Priority List can be configured. This list allows the IMG to set a priority on which clock source will get highest priority and which clock source will get lowest priority. For example, the default Timing Synchronization Priority List is configured so the IMG first determines if the Primary Reference Clock Port has a loop timing source on it. If it is does not, the IMG determines if the Secondary Reference Clock Port has a loop timing source on it. The IMG continues to check each configured clock in succession until it finds an available source.

 

Procedure

  1. Prior to configuring the Timing Synchronization Priority List, configure the Logical IMG and then the Physical IMG objects.

  2. Primary and Secondary Reference Timing are hard-coded and are automatically configured. If Primary Loop and/or Secondary Loop Timing is going to be used, configure the Primary and/or Secondary Loop timing source on the DS-1 within any Bearer or Signaling interface other than the two Signaling interfaces that have the Primary and Secondary Reference sources hard coded to them. To configure, click on either the Bearer Spans or Signaling Spans object in the configuration tree.

  3. When the Bearer or Signaling Spans pane appears, highlight one of the Bearer Interfaces in the Object Table at the bottom of the pane. Right click and select either Set Primary.

  4. Repeat for the Secondary Loop timing source. Select Set Secondary.

  5. Once all timing sources have been configured the sources need to be prioritized. Right-click the Physical IMG and select New Timing Synchronization Priority List. The Timing Synchronization Priority List pane appears as displayed below

sc_timingsyncprioritylist_10-5-0.png

  1. Click in the Timing List field under the User-Specified tab and an Arrange Items dialog box will appear. The priority is displayed from top to bottom. The uppermost entry gets the highest or first priority and then the priority decreases as you move down the list. To change the priority, highlight one of the entries and click on the Up or Down button to move the entry up or down the list. Highest priority in the screen below is the Primary Reference and lowest priority is Free Running.

sc_tsp_dialog.png
 

Note: Primary Reference and Secondary Reference are hard coded and will accept a loop timing source on Signaling interfaces 0 and 1 respectively. Primary and Secondary Loop however, can be configured on the DS-1 of any Bearer interface as well as Signaling Interface 2 and Signaling Interface 3 .

 

Below is an explanation of each of the timing references and how they are used:

Clock Source Description
Primary Reference Primary Reference is hard-coded to the DS-1 within the Signaling/Timing interface 0. The timing source does not need to be configured. Connect a DS-1 to this interface and the IMG will automatically synchronize with the T1 or E1 loop timing source.
Secondary Reference Secondary Reference is hard-coded to the DS-1 within the Signaling/Timing interface 1. The timing source does not need to be configured. Connect a DS-1 to this interface and the 2020 IMG will automatically synchronize with the T1 or E1 loop timing source.
Primary Loop Primary Loop timing can be configured on any DS-1 other than the DS-1's used for Primary and Secondary Reference timing described above. To configure, highlight one of the Bearer Interfaces in the Object Table at bottom of the Bearer Span object. Right click and select Set Primary. Once the timing source is set, the Primary Loop selection in the Timing Synchronization Priority List can be moved to a higher position as required.
Secondary Loop Secondary Loop timing can be configured on any DS-1 other than the DS-1's used for Primary and Secondary Reference timing described above. To configure on, highlight one of the Bearer Interfaces in the Object Table at bottom of the Bearer Span object. Right click and select Set Secondary. Once the timing source is set, the Secondary Loop selection in the Timing Synchronization Priority List can be moved to a higher position as required.
Free Running The Free Running source is the clock source generated internally. It is not recommended that the Free Running source be used as an external clock source used to time the network. The Free Running source is used as a backup source in the event all network timing sources have failed. The Free running timing source should always be configured as the last clock source in the Timing Synchronization Priority List.

 

Additional Information