Symptom:
Ring topology changed after TNC SSO

Conditions:
1. Have 3 Rings in total in CTC mode.

Ring 1 -> 4 PB, closed
Ring 2 -> 3 PB, open
Ring 3 -> 3 PB, closed

2. Pre-provisioned one PB in Ring 1. i.e. Just add a PB from CTC.

Ring 1 -> D1,D2,D3,D4 (before adding new PB)
then added D11  (pre-provisioned)
So Ring 1 became like as follows,
Ring 1 -> D1,D2,D3,D4,D11 

Ring 2 -> D5,D6,D7 
Ring 3 -> D8,D9,D10

3. Did TNC SSO. 

4. After SSO, CTC showing the topology as 

Ring 1 -> D1,D2,D3,D4,D11,D5 
Ring 2 -> D6,D7 
Ring 3 -> D8,D9,D10