Invalidate Next-Hop Based On Arp/Neighbor Cache State; Ldp Shortcut For Igp Route Resolution - Alcatel-Lucent 7450 Configuration Manual

Weighted Load-Balancing over MPLS LSP

Invalidate Next-Hop Based on ARP/Neighbor Cache State

This feature invalidates next-hop entries for static routes when the next-hop is no longer
reachable on directly connected interfaces. This invalidation is based on ARP and Neighbor
Cache state information.
When a next-hop is detected as no longer reachable due to ARP/Neighbor Cache expiry, the
route's next-hop is set as unreachable to prevent the SR from sending continuous ARPs/
Neighbor Solicitations triggered by traffic destined for the static route prefix. When the next-
hop is detected as reachable via ARP or Neighbor Advertisements, the state of the next-hop
is set back to valid.
Invalidate Next-Hop Based on IPV4 ARP
This feature invalidates a static route based on the reachability of the next-hop in the ARP
cache when the validate-next-hop command is enabled within the static-route-entry>next-
hop context for an IPv4 static route.
In this case, when the ARP entry for the next-hop is INVALID or not populated, the static
route must remain invalid/inactive. When an ARP entry for the next-hop is populated based
on a gratuitous ARP received or periodic traffic destined for it and the normal ARP who-has
procedure, the static route becomes valid/active and is installed.
Invalidate Next-Hop Based on Neighbor Cache State
This feature invalidates a static route based on the reachability of the next-hop in the neighbor
cache when the validate-next-hop command is enabled within the static-route-entry>next-
hop context for an IPv6 static route.
In this case, when the Neighbor Cache entry for next-hop is INVALID or not populated, the
static route must remain invalid/inactive. When an NC entry for next-hop is populated based
on a neighbor advertisement received, or periodic traffic destined for it and the normal NS/
NA procedure, the static route becomes valid/active and is installed.

LDP Shortcut for IGP Route Resolution

This feature enables you to forward user IP packets and specified control IP packets using
LDP shortcuts over all network interfaces in the system that participate in the IS-IS and OSPF
routing protocols. The default is to disable the LDP shortcut across all interfaces in the
system.
56 Router Configuration Guide