Is-Is And Ospf Support For Loop-Free Alternate Calculation - Alcatel-Lucent 7450 Manual

IS-IS and OSPF Support for Loop-Free Alternate Calculation

tunneled next-hop as the primary next-hop for a given prefix. LDP is also able of resolving a FEC
to a tunneled next-hop when the IGP shortcut feature is enabled.
When both IGP shortcut and LFA are enabled in IS-IS or OSPF, and LDP FRR is also enabled,
then the following additional LDP FRR capabilities are supported:
1. A FEC which is resolved to a direct primary next-hop can be backed up by a LFA tunneled
2. A FEC which is resolved to a tunneled primary next-hop will not have an LFA next-hop. It
The LFA SPF is extended to use IGP shortcuts as LFA next-hops as explained in
Alternate Calculation in the Presence of IGP shortcuts on page
IS-IS and OSPF Support for Loop-Free Alternate Calculation
SPF computation in IS-IS and OSPF is enhanced to compute LFA alternate routes for each learned
prefix and populate it in RTM.
Figure 52
three routes to reach router R5 from router R1.
Page 558
next-hop.
will rely on RSVP FRR for protection.
illustrates a simple network topology with point-to-point (P2P) interfaces and highlights
Loop-Free
562.
7450 ESS MPLS Guide