Heterogeneous services

I am trying to set up heterogenous service on Linux to MSSQL and I have the question:

TNSNAMES.ORA

hsmsql =
(DESCRIPTION=
(ADDRESS=
(PROTOCOL = tcp)(HOST = oracle_host)(PORT = 1521))
(CONNECT_DATA=
(SID = msql) – match with ODBC source name and SID in listenner.ora
)
(HS = OK)
)

LISTENER.ORA

LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = oracle_host)(PORT = 1521))
)
)
)

SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC=
(SID_NAME=msql) -- match with SID in tnsnames.ora
(ORACLE_HOME=C:\oracle)
(PROGRAM=hsodbc) -- hsodbc is an executable
)
)



About the SID name, I unsderstand that the SID name has to be the same between TNSNAMES and LISTENER.ora; however, where do we get this SID NAME ????

Was it suppose to be the same with the SID name where you are going to create the link on later????