The read-only transport property of an RTCRtpSender object provides the RTCDtlsTransport object used to interact with the underlying transport over which the sender is exchanging Real-time Transport Control Protocol (RTCP) packets.

This transport is responsible for receiving the data for the media on the sender's track.

An RTCDtlsTransport object representing the underlying transport being used by the sender to exchange packets with the remote peer, or null if the sender isn't yet connected to a transport.

When the RTCRtpSender is first created, the value of transport is null. This is replaced with an RTCDtlsTransport once the sender's transport has been established.

Note that when bundling is in effect—that is, when the RTCPeerConnection was created with a configuration object whose bundlePolicy is max-compat or max-bundle—multiple senders may be sharing the same transport; in this case, all of them are using the same connection to transmit and/or receive RTP and RTCP packets.