What * means in the output of show ip route x.x.x.x command?

[rezaalikhani]

Hi all;

Please consider the following output:

What "*" means in the above output?

Thanks

[Georg Pauwen · Accepted solution]

Hello,

if you look at the output, you currently have two paths, one through tunnel 1000, the other through tunnel 2000. Based on what kind of load balancing scheme your router runs, the '*' means that, at the time you issue that command (sh ip route 17.68.20.0), traffic is using the link through tunnel 1000. Chances are that if you issue the command multiple times, the '*' will switch the the path through tunnel 2000, as this is being used as well (again, based on where the traffic is flowing through).

If you only have one path, the '*' for will obviously always be there for only that one path.

Does that make sense ?

[Giuseppe Larosa]

Hello @rezaalikhani ,

the '*' should just mean a sort of primary path because for example it is older.

In most cases per flow load balancing will occur over both tunnels tunnel 2000 and tunnel 1000 using CEF load balancing math that includes IP SA , IP DA and a seed selected at router startup.

It is an EXOR at bit level  of less meaningful bits of IP SA, IP DA and seed. The result provides an index that is used to decide the outgoing link for the given flow.

Hope to help

Giuseppe