Juniper MPLS RSVP LSP make before break query

Hi all,

​

I'm trying to understand the behaviour of Juniper MPLS RSVP LSPs specifically when it comes to reoptimising the path.

​

The default mode is Fixed Filter style. My understanding is that for this style the old path has to be torn down before the new path can be established due to the requirement of not doubling up resource allocations. Is this correct?

​

I have done some documentation reading and came across this documents:

https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/make-before-break-achieving-for-lsps.html

https://www.juniper.net/documentation/en_US/junos/topics/usage-guidelines/mpls-configuring-adaptive-lsps.html

This forum post too: https://forums.juniper.net/t5/Routing/mpls-gt-path-gt-adaptive-knob-use-case/td-p/145652

​

It seems to confirm my initial assessment that Juniper will only do make before break when adaptive is configured and the style is change to Shared Explicit.

​

Am I on the right track here?

​

Thanks in advance,

H