After introducing an ACX7100 device into the network, users may encounter issues when establishing ISIS adjacencies. Specifically, logs may indicate a problem with programming the Packet Forwarding Engine (PFE). The error messages suggest an invalid configuration during the route programming process, resulting in routes being present in the routing table but remaining unreachable.

• ISIS adjacency is established, but logs indicate issues with PFE programming.

• Error logs similar to the following may be observed:

  evo-pfemand[PID]: %USER-4-EVO_PFEMAND_ROUTE_PROGRAM_FAILED: Failed to program addition for the unknown(0) route X.X.X.X with mask for the vrf id 0 reachable via next hop with index 536923342 with an error - invalid configuration specified
   evo-pfemand[PID]: %USER-3-EVO_PFEMAND_ASIC_PROGRAM_FAILED: Failed to program the hardware with an error - invalid configuration specified
  
  

  Despite routes being present in the routing table, they are not reachable, as seen in the ping test results:

  PING X.X.X.X (X.X.X.X) 56(84) bytes of data.
  --- X.X.X.X ping statistics ---
  6 packets transmitted, 0 received, 100% packet loss, time 5122ms
  
  
  

  The following error may also be observed on the ACX7100:

  USER-4-EVO_PFEMAND_ROUTE_PROGRAM_FAILED: Failed to program addition for the unknown(0) route with mask for the vrf id 0 reachable via next hop with index with an error - invalid configuration specified.
  

To resolve this issue, the following configuration is needed:

1. Apply the following command to adjust the hardware database profile:

   set system packet-forwarding-options hw-db-profile l3-xl
   

2. After applying this configuration, reboot the entire chassis to ensure the changes take effect.

3. For a permanent fix, refer to the solution provided in PR1779524. More details can be found at the following link: PR1779524.

4. By applying the necessary configuration and rebooting the chassis, the issue with route programming should be resolved, allowing the routes to become reachable.