Data API will use SCTP and not TCP so there are some considerations for implementing HTTP over SCTP based channel. Also it depends on what Congestion control the SCTP implements/enables.
There are also NAT traversal considerations which would make connection setup longer when compared to HTTP based infrastructure. Of course, as the underlying transport matures over time (or people build extensive libraries in JS to over come the deficiencies), we will see if data API will become larger than its current vision (of serving data in-band with multimedia)
PeerConnection API supports traditional NAT traversal mechanisms though there are a very, very, very small number of cases that can be handled by a privileged user that can't be emulated in the browser.
There are also NAT traversal considerations which would make connection setup longer when compared to HTTP based infrastructure. Of course, as the underlying transport matures over time (or people build extensive libraries in JS to over come the deficiencies), we will see if data API will become larger than its current vision (of serving data in-band with multimedia)
[RELIABLE vs UNRELIABLE DATA CHANNEL]http://tools.ietf.org/html/draft-ietf-rtcweb-data-channel-01...
[CONGESTION CONTROL] http://tools.ietf.org/html/draft-ietf-rtcweb-data-channel-01...