OSPF shortcuts efficiently re-routes traffic within the same OSPF routing domain through Label Switched Paths (LSP) domains. Traffic routing is primarily done by using the redundant paths of the LSP tunnels, which ensures optimized usage of the available bandwidth, better traffic engineering, and fast re-routing.
OSPF shortcuts can also be used to steer traffic over specific paths (routes) and thus can be used to address any node/link failures or to address any capacity shortages.
Note
OSPF Shortcuts is applicable only to OSPFv2. It is not applicable for OSPFv3.OSPF shortcuts can only be applied on default VRF, as MPLS is only supported on the default VRF.
OSPF shortcuts is only applicable for IPv4 versions of OSPF and OSPFv2. It is not supported for IPv6.
LSP tunnel destination should match the OSPF Router ID of the Label Edge Router (LER) for the OSPF shortcut to work. Since OSPF identifies other routers in the routing domain through the Router-ID, the LER is identified using the OSPF Router-ID.
The LSPs used for OSPF Shortcut must originate and terminate within the same OSPF area. Since Shortest Path First (SPF) tree is calculated per area, the egress LER must be identified as a router within the same OSPF area as the ingress LER.
OSPF shortcut routes can be distributed to other protocols if redistribution is enabled.
Relative Metric option (RFC 3906, Section 4.1) is not supported for OSPF LSP shortcuts.