What is the relationship between .NET Framework Data Provider for SQL Server and Sql Native Client?

I'm using .NET Framework Data Provider for SQL Server. I'm reading this http://msdn2.microsoft.com/en-us/library/system.data.sqlclient.sqlconnection.connectionstring.aspx. Some of the keywords have alternatives. I want to know which alternative is recommended and why. For examples, Example #1:
the keyword Initial Catalog is listed as an alternative to the keyword Database. Should I use Initial Catalog or Database and why?
Example #2:
Should I use the name or network address of the instance of SQL Server and why?
Also, some keywords can accept true, false, yes, and no. I don't think there is any difference in using true or yes. But I wonder whether there is any recommneded standard.
In MSDN Library, the value sspi for the keyword Intergrated Security or Trusted_Connection is stated as strongly recommended. I remember reading a thread somewhere using the value true does not work in a case but using the value sspi will work. What is the difference between sspi and true?
Keywords that I'm interested to know which alternative is recommended and why
Connect Timeout
Connection Timeout
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Data Source
Server
Address
Addr
Network Address
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Initial Catalog
Database
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Integrated Security
Trusted_Connection
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Network Library
Net
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Password
Pwd
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Does the connection string I created for .NET Framework Data Provider for SQL Server actually get mapped to something in Sql Native Client? If yes, where can I find more information about this? If no, does it mean that there is no relationship between .NET Framework Data Provider for SQL Server and Sql Native Client?
I'm not sure where I should post this kind of questions since it is related to both .NET and SQL Server.

If you use the key word Password in a parameter of a stored procedure then the information will be encrypted.
To see this run a trace, when you pass a password to @Password the sp will be encripted protecting the value of the parameter. This will not happen with "pwd"
I would not use initial catalog, cause dropping and adding back a username will cause the default database to be lost and as a result you connection will fail when looking for the objects. If you state the db in the connection then you will not experience this issue.

Hi clarkbaker1964,
Thanks for the reply. I don't quite understand your statement about initial catalog. Can you elaborate it?
Thanks.

I dont know if its the right answer, probaly few of the things are for backword compatiablity? the question is very basic and i have no answer for it. probably some body very good at microsoft can help you.
its just asking a question why is 8 bits = 1 byte and not 10 bits = 1 byte. i dont have an answer for it.