[c-nsp] balancing load 4 static routes

[Bas]

Hi all,

On a sup720 running sxf4 I have a BGP session with a peer between
loopback addresses. There are four static routes pointing to the
loopback address of the peer.

For some reason one of the 4gige interfaces is loaded twice as much as
the other interfaces.
When I shut this interface traffic is balanced over three remaining
interfaces evenly.

sh ip cef <peer-ip> shows all four entries.

Is there some kind of algorithm causing this?

Thanks