XiTOCO Express Interface (Xi / OPC .NET) Wrapper Server

The XiTOCO Express Interface (Xi / OPC .NET) server wraps to classic OPC DA, OPC HDA and OPC AE servers. Only a simple configuration is required to specify the OPC servers to be wrapped.

The XiTOCO Express Interface (Xi / OPC .NET) server wraps to classic OPC DA, HDA and AE servers. Only a simple configuration is required to specify the OPC servers to be wrapped.
Xi client applications can get current data, historical data and events from classic OPC server through a single Xi server.

The Express Interface is designed to provide new .NET client applications a simple .NET interface for easy access to OPC DA (Data Access), OPC HDA (Historical Data), OPC A&E (Alarms & Events), and to proprietary Alarm and Event historians.

To minimize DCOM issues the XiTOCO server should be installed on the same as the OPC DA/HDA/AE servers. The Xi clients can access the Xi server from remote location using communication settings with the appropriate security levels.

XiTOCO Security
The Express Interface specification was designed with communication security as a main consideration. Management and data read/write operations are handled through different endpoints, which can be separately configured with appropriate communication settings. Xi management methods associate handles with object identifiers and the read/write data methods only communicate handles with the data. This makes data hard to interpret by an eavesdropper even if it's communicated without encryption.
The XiTOCO converter requires the management endpoint to be configured for secure communication. This ensures good security without reducing the data exchange performance.

Access control on Object level The Xi interface and WCF security control the access to the server. Clients that are allowed access to the server have access to all objects of the server. The Advosol Xi servers implement an additional security layer. The server configuration can restrict the object access individually for each client. Browsing the server shows only the objects this client is allowed to access. The screen shots on the right show the object structure of the same Xi server for different clients. The server is configured to allow one client access to all objects but to allow other clients only read access to a few objects. The clients are identified by either the Windows user name or by a X509 certificate. Access can further be restricted to a particular client IPC address. The access rights can be restricted to e.g. deny write access, deny access to a set of object or allow access to only a configured set of objects. The XiConfig utility provided with the Advosol Xi servers makes the server configuration simple. All configuration and security settings can be made with this one utility. XiConfig also supports the creation and management of X509 certificates. Object access restrictions can be interactively edited. The Xi server can be browsed and dragged to a list of objects that are either allowed or blocked for particular clients. The configuration is stored in an XML file that is processed by the server at startup.	Client with full access rights	Client with read-only access to an object subset.

XiTOCO as a Tunneler Solution
XiTOCO used in combination with the DAEtoXi Converter DA Server converts OPC DA/AE to Xi and back to OPC DA/AE. Remote OPC DA/AE servers can be accessed through an OPC Xi connection.

The Express Interface communication has significant advantages over Tunneler products: The communication can be configured to a security level appropriate for the application TCP or HTTP communication can be choosen. TCP communication offers high performance but requires firewall configuration. HTTP communication on standard ports works without configuration efforts. The Xi communication interface is used instead of a proprietary Tunneler interface. Either side converter can easily be replaced with any Xi client respectively server. Can act as a security gateway to restrict object access based on the client credentials.

XiTOCO Versions
The XiTOCO converter server is available in versions with different functionality:

• a low cost version that handles only one DA server
• versions for any combination of OPC DA, HDA, AE servers
• a full featured version supporting OPC DA, HDA and AE servers

Requirements

• Windows XP, Vista, Windows 7/8, Windows Server 2003/2008
• .NET 3.5 SP1 or 4.0/4.5 with WCF
• PNRP/IP6 for Xi server discovery

XMLDA.NET is a .NET XML DA client component that supports access to OPC DA and XML DA servers. The OPC client application can be designed as an XML DA web service client and ican be built as a Windows Forms orASP.NET application. All DCOM handling is XMLDA.NET internally.