Swap route priority in different routing tables

[Gianguido]

Hi all,

I have two sites, two links in between, one is high bandwith/high 
latency (HB), the other is low bandwidth/low latency (LB), bird 1.6.8.
I neet all traffic to flow on HB link except for real time, which in my 
case is RTP that goes through LB. To achieve this, I'm using PBR with 
two kernel routing tables: main should have HB route as preferred route, 
low_latency should have LB as preferred. Should any of the two fail, all 
traffic needs to be routed on the other link.

Problem is to properly populate the tables. Local interface states are 
not reliable in terms of actual link availability, and anyways I'm 
already using OSPF in the whole network setup.
Currently in bird OSPF runs and populate the main table, then I have a 
dedicated pipe+kernel populating the low_latency one. Of course OSPF 
elects the preferred route based on link costs, so only that route gets 
into bird routing table, and it's the only one that can be eventually 
piped into low_latency table. This way, all traffic goes either HB or LB 
depending on OSPF link costs because the two routing tables are identical.

Is there a way to get both routes learnt through OSPF into bird table 
and then apply a filter to the pipe in order to swap the preference when 
propagating those routes into the low_latency table? Or any other 
suggestion to rework this in order to achieve the goal above?

thanks

G.