The "show interface ip brief" command shows serial interface as UP; but T101 session does not come up
Router# show ip interface brief Interface IP-Address OK? Method Status Protocol FastEthernet0/0 10.64.69.206 YES NVRAM up up Serial0/1/0 unassigned YES NVRAM up up Serial0/1/1 126.96.36.199 YES NVRAM up up Substation-Router#show t101 session summary Interface Link Addr. ASDU Addr. Session Name Role Link State Se0/1/0 3 3 T101 Master Down
Enter the show t101 sess session-name command and look for the fields: Link addr Length and Link Address.
Router# show t101 sess T101
Link : Point-to-Point Mode: Unbalanced Role: Master Link Address: 3 ASDU Address: 3 Link State: Down Link Address Len: 1 bytes Poll Interval: 1000 msec Retry Count: 10 Retry Interval: 1000 msec ASDU Address Len: 2 bytes CoT Len: 1 bytes Object Addr Len: 2 bytes Router#
Verify that the RTU has been configured with the same Link Addr Len and Link Addr fields.
If above-mentioned configuration is not done, then make sure that the RTU and the router connected to RTU have the same Link Address and Link Address Length.