Session Agent Out of service in Standby SBC

Dear Team,

We are observing one of Session agent  “out of service” state in standby SBC and is “in-service” active SBC.

Why this discrepancy in active/standby SBC. How to make the session-agent In service in Standby SBC.

Session Agent : SIP100

Active SBC:

###########

SBC01-1# sh sip agent SIP100

19:44:03-55

Session Agent SIP100 [In Service]

                        ---Period--------------------Lifetime-----

                          Active  High  Total         Total  Permax  High

Inbound Session             5756  5772   1555         1704601  2761   10940

Standby SBC:

###########

ACtive SBC01-2# sh sip agent SIP100

19:44:03-55

Session Agent SIP100 [Out of Service]

                  ---Period--------------------Lifetime-----

                          Active  High  Total         Total  Permax  High

Inbound Session             5257  5372   656         8704601  2761   10940

Thanks in Advance.

Regards,

Durai