Is there an example that would demonstrate extensibility and the PDU safe relay mechanism?

Yes, this example demonstrates how you can make use of the PDU relay mechanism when the sender and receiver work with different versions of the same protocol and the receiver is not aware of the extension additions sent.

The sender application has a more recent version of the protocol with all the extension additions known. The receiver application has an older version of the same protocol which is not aware of the extension additions sent. The receiver application gets the unknown extension additions in the decoded PDU, changes the PDU as needed based on the version of the protocol it works with (modification not shown in this example), re-encodes the decoded PDU using its older version of the protocol and sends it back to the same or another receiver (relays) who is aware of the extension additions and who successfully decodes the PDU which was encoded by the sender with the older version of the protocol.

This test uses the ALIGNED variant of PER but it can be run using any other encoding rules, like BER/DER/UPER. The following ASN.1 compiler command line was used:

asn1 -relay relay.asn -per -ber -uper -der -nounique

If you target an operating system other than Windows or UNIX, you can also use either of these zip files and discard the Windows- or UNIX-specific files.

Select one of the links below to download the example:

• relay.windows.zip 29 KB
• relay.unix.zip 4 KB

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The samples included with some of the Knowledge Center answers are meant for your general understanding of the OSS products. Different versions of the products might produce slightly different outputs. Consult the products documentation and samples for the most up-to-date products information and code examples.