Alcatel-Lucent 7950 SR User Configuration Manual page 359

A) The algorithm splits the LFA next-hops into two sets:
B) The algorithms continues with first set if not empty, otherwise it continues with second
C) If the second set is used, the algorithm selects the tunneled LFA next-hop which endpoint
D) Within the selected set, the algorithm splits the LFA next-hops into two sets:
E) If there is more than one LFA next-hop in the selected set, it will pick the node-protect
F) If there is more than one LFA next-hop within the selected type, then it will pick one
G) If there is more than one LFA next-hop within the selected type (ecmp-case) in the first
H) If there is more than one LFA next-hop within the selected type (ecmp-case) in the second
Loop-Free Alternate Calculation for Inter-Area/inter-Level Prefixes
When SPF resolves OSPF inter-area prefixes or IS-IS inter-level prefixes, it will compute an LFA
backup next-hop to the same exit area/border router as used by the primary next-hop.
7950 SR OS MPLS Configuration Guide
 the first set consists of direct LFA next-hops
 the second set consists of tunneled LFA next-hops. after excluding the LSPs which
use the same outgoing interface as the primary next-hop.
set.
corresponds to the node advertising the prefix.
 If more than one tunneled next-hop exists, it selects the one with the lowest LSP
metric.
 If still more than one tunneled next-hop exists, it selects the one with the lowest
tunnel-id.
 If none is available, it continues with rest of the tunneled LFAs in second set.
 The first set consists of LFA next-hops which do not go over the PN used by
primary next-hop.
 The second set consists of LFA next-hops which go over the PN used by the primary
next-hop.
type in favor of the link-protect type.
based on the least total cost for the prefix. For a tunneled next-hop, it means the LSP
metric plus the cost of the LSP endpoint to the destination of the prefix.
set, it will select the first direct next-hop from the remaining set. This is not a
deterministic selection and will vary following each SPF calculation.
set, it will pick the tunneled next-hop with the lowest cost from the endpoint of the LSP to
the destination prefix. If there remains more than one, it will pick the tunneled next-hop
with the lowest tunnel-id.
Label Distribution Protocol
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