Solution : https://service.sap.com/sap/support/notes/53446 (SAP Service marketplace login required)
Key words : 
cd $oracle-homerm -rf bin dbup ddbo guicommon lib network tcppa \ocommon plsql rdbms tcp tk2 xa core3 guicommon2  \names netman oacore2 slax sqllib sqlplus srvmgr, cd <instdir>    cp /sapmnt/<sapsid>/exe/install/netv2, line                     orasrv        1525/tcp        #oracletlisrv        1527/tcp        #oracle, database softwareconfigure oracle sql net version 2           notencr, $oracle-home/bin/orasrvdec digital unix, hos@ editthe host startup/shutdown script, configure oracle sql net version 2you, rgs rm $oracle-hobe/orainst/unix, orainst troubleshootingwrong user inputall user input, setenv tns_admin /usr/sap/trans            @ note
Related Notes : 
       
| 65721 | Additional Info: Upgrading to Japanese 30F ORACLE | 
| 34479 | Collective note for problems with SQL-Net V2 ORACLE |