Cisco Cisco Packet Data Gateway (PDG)

 

▄  SaMOG Administration Guide, StarOS Release 16  

SaMOG has the ability to recover fully created sessions in the event of process level or card level failures.  

This feature supports the following types of session recovery: 



 

Task level recovery: SaMOG sessions are recovered when a Session Manager task serving the session is 

terminated due to a software error. 



 

Card level recovery: SaMOG sessions are recovered when the entire PSC/DPC card hosting the Session 

Manager fails, and all the tasks running on that card have to be recovered. The SaMOG sessions can be 
recovered in the event of a PSC/DPC card failures in the following scenarios: 



 

Unplanned card failure: SaMOG can recover tasks running on the failed card to the standby card by 

fetching the CRR information from the peer Session Managers and AAA Managers in the other card. 



 

Planned card migration: The system administrator can migrate the sessions from one PSC/DPC card 

to a standby card using the CLI. Planned migration can be performed by transferring the entire 
memory contents from the source card to the destination card, re-opening the sockets, and updating 
the NPU flows. 

  In this release, card level recovery and npusim recovery are not supported on the virtualized platform 

(QvPC-SI).  

When the Session Recovery feature is enabled for the SaMOG Gateway using the CLI, the Session Manager maintains a 
backup of the session critical information with the AAA Manager that has the same instance number. A paired AAA 
Manager with the same instance number as the Session Manager is started on a different PSC/DPC card. When a failure 
is detected, the Call Recovery Record (CRR) that contains the backed up information is fetched from the AAA 
Manager, and the sessions are re-created on the recovered Session Manager. 

As the SaMOG session recovery feature makes use of the existing StarOS IPSG framework, new fields are added to the 
IPSG session recovery record to recover attributes specific to the SaMOG session (For example: GRE end point 
address, SaMOG EGTPC information, etc). 

The Session Recovery feature requires a minimum of four PSC/DPC cards (3 active and 1 standby). One PSC/DPC card 
will be used the DEMUX managers and VPN manager, two PSC/DPC cards will be used by the Session manager and 
AAA manager, and one PSC/DPC card will be used for standby.  

  For more information on session recovery support, refer to the Session Recovery chapter in the 

System Administration Guide.