[ns] Following an alternative path when a link down

[Bil Geyts]

Hi,

1 ---- 2 ---- 3
       |      |
       |      |
       4 ---- 5

Above is my topology.
1 is source.
4 is sink.
I can send packages from 1 to 4 over 2 ( The Followed Path is 1-2-4 ).
But when I down the link between 2-4. All packages dies.

When the link between 2-4 goes down, I want all packages to follow the path
1-2-3-5-4.

How can I do that?

Thanks in advance,

Bil