Control of dynamic bypass LSP creation is by a combination of global level configurations and interface level configurations. An MPLS interface with a dynamic bypass enabled in it is able to create a dynamic bypass LSP to provide a backup path for the protected LSP traversing out of that interface.
Creation of a dynamic bypass LSP to a destination MP follows the same order as the FRR merge point selection order.
Dynamic bypass LSP creation must meet the following criteria:
There are no existing static bypass or dynamic bypass LSPs to satisfy the facility protected LSP backup path request.
The creation of the dynamic bypass is allowed under the current configuration for the protected interface.
The creation of the dynamic bypass does not exceed the configured or default system limits under the current state.
There is an available path to setup the dynamic bypass LSP that can fulfill the backup request constraints.
Facility protected LSP PLR originate the dynamic bypass LSP with a merge point as the destination.
Merge point selection for dynamic bypass creation uses the existing order of the backup path merge point selection. (When not requesting node protection, reverse the order of step 1 and 2.)
Tries to create a dynamic bypass LSP to the NNHOP merge point.
When step 1 fails, then attempts to create a dynamic bypass LSP to the NHOP merge point.
When step 2 fails, then attempts to create a dynamic bypass LSP to the NNNHOP merge point.
When step 3 fails, then attempts to create a dynamic bypass LSP to the NNNNHOP merge point.
This continues until the protected LSP destination node is the merge point.
Dynamic bypass creation order
The user can create a maximum of 500 bypasses in a system. This includes both static bypasses and dynamic bypasses.
