Arrange two tables and get result
I'm not sure this is what are you looking for because IMHO you must deal with recursive functions.

Using only centers table

select IdCenter, IdNode
from
(
    select     ce.IdCenter, ce.IdNodeIn IdNode, 0 as nodeOrder, Row
    from       center ce
    union all
    select     ce.IdCenter, ce.IdNodeOut IdNode, 1 as nodeOrder, Row
    from       center ce
) x
order by Row, idCenter, nodeOrder;


Using connection table to set the correct order

with rowOrder as
(
    select    ce.IdCenter, ce.IdNodeIn, ce.IdNodeOut,
              case when co.Row is null then 3 else co.Row end Row 
    from      center ce
    left join connection co
    on        co.IdCenterFrom = ce.IdCenter
) 
select IdCenter, IdNode 
from (
       select IdCenter, IdNodeIn IdNode, Row from rowOrder
       union all
       select IdCenter, IdNodeOut IdNode, Row from rowOrder
     ) x
order by Row;


This is the final result on both cases:

| IdCenter | IdNode |
|----------|--------|
| 470      | 1      |
| 470      | 5218   |
| 22       | 5298   |
| 22       | 1      |
| 20       | 5242   |
| 20       | 5284   |


Rextester here