wolfSSL release 5.7.4 includes an exciting new feature. We have implemented Connection ID (CID) support for DTLS 1.2 (RFC 9146). CID is a new feature in DTLS 1.2 that allows for better handling of connection migration. Without it, DTLS connections are tied to the IP 5-tuple making it unable to recover the connection if one of the peers changes their address. This is where CID comes in. This feature is used to associate DTLS records from a new IP address to an existing connection. This is especially useful for mobile devices that may switch between Wi-Fi and cellular networks, or for any device that may change IP addresses during a connection.
Using CID’s in wolfSSL is easy. Just setup your connection as usual, but call wolfSSL_dtls_cid_use() to enable the CID feature on the connection. This will enable the CID on your side of the connection. To request the peer to use a CID, use wolfSSL_dtls_cid_set().
If you have any questions regarding CID’s in DTLS 1.2 or 1.3, please contact us at facts@wolfssl.com or +1 425 245 8247.
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