When the number of L2TP sessions reaches the configured maximum value, the LNS sends an out-of-resource result code (4 or 5) in a CDN (Call-Disconnect-Notify) message to the LAC. This signals the LAC to fail over to another LNS that has the resources for more sessions.
Some third-party LAC implementations fail over only when they receive result code 2 sent in the CDN from the LNS. You can override result codes 4 and 5 with result code 2 on the LNS to enable such routers to fail over to another LNS. These codes have the following meanings:
The following sections describe how to override the result codes and how to display the current code values.
You can override the out-of-resource result codes 4 and 5 by issuing the session-out-of-resource-result-code-override command on the LNS.
- host1:boston(config-l2tp-dest-profile-host)#session-out-of-resource-result-code-override
You can view the current override setting for the LNS result codes in the L2TP destination profile.
ERX(config)#show l2tp destination profile boston
L2TP destination profile boston
Configuration
Destination address
Transport ipUdp
Virtual router default
Peer address 10.10.76.12
Statistics
Destination profile current session count is 0
Host profile attributes
Remote host is LAC
Configuration
Tunnel password is TunnelPass
Local host name is LNS
Local ip address is 46.1.1.2
Disconnect-cause avp is enabled
Tunnels are single-shot
Override out-of-resource-result-code is enabled
Statistics
Current session count is 0
1 L2TP host profile found