Just want to confirm.
We know that bgp communities are Optional transitive, which means if my upstream router does not have this community configured or does not even understand communuty it should pass it to all its neighbours.
Scenario:
isp isp
R1---->R2--->R3---->R4 . (all ebgp or ibgp, should not matter)
If I tag some routes with community on R1 and send it to upstream router R2, even though R2 might be unaware of this community ( do not create this community) or does not understand them it should pass it to R3, and finally I can match routes on R4 based on community I configured on R1
Cisco routers should use "neighbor 3.3.3.3 send-community" command in order to be able to pass communities to other routers. Otherwise router will receive route with update but will advertise without it.
What is default behaviour on Juniper routers? will they by default pass communties to other routers unless I configure policy to remove the communties?
Thanks,