When settings PTP SYNC for co-located ODU's (regardless if there is an external timing device or not -  setting your CLUSTER MASTER ODU should be what:

1. Is it the link with the nearest link distance, or,

2. The link with the farthest link distance?

Thanks again...


Hi Gerry,

I'm not 100% sure I understand the question. If this answer doesn't satisfy then please come back for more.

You configure TDD Synchronization in PTP 650 is by setting Max Burst Duration, TDD Frame Duration, TDD Frame Offset and Slave to Receive Gap in the Installation Wizard. Together, these determine characteristics of the TDD frame, and the phase relationship between the TDD frame and the GPS reference. There's some maths needed to find the correct settings here, and we normally suggest using LINKPlanner for this.

You're right that frame duration depends on link range. It must be big enough to allow for the longest link range in the network.


Hi Mark,

Appreciate this a lot. Yes I understand to find and set the correct frame time slot durations using LP. My question is that, assuming I have 4-links which requires TDD synchronization and these links i have distances as follows, 1,2,4,6 km. And from these given link distances, which ODU will be selected as the MASTER CLUSTER ODU? Is it with the shortest link distance or the longest?

Thanks again.

Hi Gerry,

I think I understand the question now.

You can select any of the collocated ODUs as the Cluster Master. You don't need to pick the one with the longest or shortest link. You do need to think about the daisy chain wiring of the PTP SYNC units though. The Cluster Master must be the first unit in the chain, like this:


Thanks Mark...