Original text:
Protocol.  However, TLS must run over a reliable transport channel - typically TCP RFC0793. <del> There are applications that utilize UDP as a transport and to offer communication security protection for those applications the Datagram Transport Layer Security (DTLS) protocol has been designed.  DTLS is deliberately designed to be as similar to TLS as possible, both to minimize new security invention and to maximize the amount of code and infrastructure reuse. DTLS 1.0 was originally defined as a delta from TLS 1.1 and DTLS 1.2 was defined as a series of deltas to TLS 1.2.  There is no DTLS 1.1; that version number was skipped in order to harmonize version numbers with TLS.  This specification describes the most current version of the DTLS protocol aligning with the efforts around TLS 1.3. </del>  Implementations that speak both DTLS 1.2 and DTLS 1.3 can interoperate with those that speak only DTLS 1.2 (using DTLS 1.2 of The following terms are used: <del> client: The endpoint initiating the TLS connection. </del>  connection: A transport-layer connection between two endpoints. session: An association between a client and a server resulting from a handshake. <del> server: The endpoint which did not initiate the TLS connection. </del>  The reader is assumed to be familiar with the TLS 1.3 specification since this document defined as a delta from TLS 1.3. 8. <del> Since TLS 1.3 introduce a large number of changes to TLS 1.2, the </del>  list of changes from DTLS 1.2 to DTLS 1.3 is equally large.  For this reason this section focuses on the most important changes only.

Reviewer comments:
Add references to RFC 768: UDP RFC 4347: DTLS 1.0 RFC 4346: TLS 1.1 RFC 6347: DTLS 1.2 RFC 5246: TLS 1.2 in the Introduction section. Currently they are mentioned but with no citations.

Revised text:
Protocol.  However, TLS must run over a reliable transport channel - typically TCP RFC0793.  <ins> There are applications that utilize UDP RFC0768 as a transport and to offer communication security protection for those applications the Datagram Transport Layer Security (DTLS) protocol has been designed. DTLS is deliberately designed to be as similar to TLS as possible, both to minimize new security invention and to maximize the amount of code and infrastructure reuse. DTLS 1.0 RFC4347 was originally defined as a delta from TLS 1.1 RFC4346 and DTLS 1.2 RFC6347 was defined as a series of deltas to TLS 1.2 RFC5246.  There is no DTLS 1.1; that version number was skipped in order to harmonize version numbers with TLS.  This specification describes the most current version of the DTLS protocol aligning with the efforts around TLS 1.3 I-D.ietf-tls-tls13. </ins> Implementations that speak both DTLS 1.2 and DTLS 1.3 can interoperate with those that speak only DTLS 1.2 (using DTLS 1.2 of The following terms are used:  <ins> client: The endpoint initiating the DTLS connection. </ins> connection: A transport-layer connection between two endpoints. session: An association between a client and a server resulting from a handshake.  <ins> server: The endpoint which did not initiate the DTLS connection. </ins> The reader is assumed to be familiar with the TLS 1.3 specification since this document defined as a delta from TLS 1.3. 8.  <ins> Since TLS 1.3 introduces a large number of changes to TLS 1.2, the </ins> list of changes from DTLS 1.2 to DTLS 1.3 is equally large.  For this reason this section focuses on the most important changes only.