Hello,
wrote:
I know I can use multipath in BGP to achieve load balancing but can I do something similar in a forwarding routing instance with imported BGP routes?
If Your eBGP paths are all equal up to a router-id , and You are using Local Preference/LP in the BGP import policy in GRT to prefer one of the paths in GRT, then You just need to equalize back the LP in RIB-group import policy, and enable "routing-options multipath" under the instance config. Then You should see #[Multipath/255] route under that instance.
If Your BGP paths are unequal :
1/ if they are having different AS_PATH lengths, then You could use "as-path-prepend" knob to equalize them but JUNOS does not support parameterized BGP attributes, so You'd need extensive scripting work to automatically react on ever-changing AS_PATH lengths
2/ if they are having different MED values, You can rewrite MED in RIB-group import policy, just like LP
3/ ditto for Origin
HTHY
Thx
Alex