Before deciding which DP4 networking configuration to use, you should consider whether or not you should really be using it at all. Refer to Alternatives to DP4 Networking for some possible alternatives.
Once you have decided you do want to use DP4 networking the next step is to decide on a Resilience Architecture (assuming you need one.)
The final stage in deciding the appropriate configuration for a particular machine is to analyse where databases will be accessed. The table below summarises the possible scenarios and your available options for each of them.
| Does machine have DP4 databases? | Does machine use DP4 databases elsewhere (including indirectly with DP4 Thin Client) ? | Do other machines use DP4 databases on this machine or use this machine as a DP4 Terminal Server? | Suitable Configurations |
|---|---|---|---|
| No | Yes | not applicable | (Simple) Client Only
Networking |
| Yes | No | No | Standalone DP4 |
| No | Yes | (Simple) Server Only Networking | |
| Yes | No | Local Database
Resilience Client Multiple Resilience Client Named Connection Configuration |
|
| Yes | Yes | Named Connection Configuration |
The table above is sufficient to choose the correct configuration unless this machine acts as a client of other machines. In the latter case your choice of which configuration to use may be limited by two other factors:
Are you use a network protocol other than TCP/IP, or running on a Legacy operating system?
If the answer to either of these questions is Yes then you cannot use the Named Connection configuration.
Does this machine require access to databases on more than one other machine?
If the answer to this question is Yes, and your answer to question 1 was also yes, you must use a Multiple Resilience configuration.
If the answer to this question is No, then there is probably no point in using either Named Connection or Multiple Resilience configurations, unless the answer to this question is Yes for some other machine that is part of the system, and you wish to use the same configuration everywhere so far as is possible.
In the case where you are using TCP/IP protocol and do require access to multiple machines you may still have more than one possible configuration. The following should help you decide which to use:
If you need support for distributed transactions, where a single transaction updates the database on more than one machine at once, or if a single instance of a program accesses data from more than than one remote server and you want to minimise the amount of awareness the application has of this, then you should use a multiple resilience configuration.
On machines where you would like to be able to use the DP4 Thin Client to run applications against remote servers you must not use Multiple Resilience configurations. (However, a Multiple Resilience Combined Client/Server can act as an application server for DP4 Thin Clients.)
If you are still unsure of the most appropriate configuration then please refer to the Comparison of DP4 networking Configurations.