SRT (Secure Reliable Transport) is an open-source video transport protocol. It optimizes streaming performance over unpredictable networks such as the Internet by dynamically adapting to real-time network conditions. It is best suited to transmit video and/or audio over the public Internet. SRT also copes well with highly fluctuating bandwidths. The quality of the transmission improves with an increase in latency. Multiple SRT streams from the same remote site arrive at the receiver simultaneously if all streaming parameters are set the same.
SRT is based on the UDP protocol. UDP is a so-called connectionless protocol. The previously known TCP had too many disadvantages regarding speed. TCP is intended for applications, which depend on a complete and secured transmission. UDP, however, does not depend on an existing connection but simply sends its data to a known address on a known port. But this also means that the sender does not know whether his sent data packets have arrived. While TCP sends acknowledgements when receiving data, UDP does without. This has the advantage that the packet header is much smaller and the transmission path does not have to transmit acknowledgements. UDP was constantly further developed to RTP and finally to SRT. The further developed protocols can request lost packets again within a certain range and also in terms of security SRT was satisfied with a maximum AES265 encryption. The disadvantage of SRT regarding port forwarding will be eliminated with the future RIST protocol. As with SRT, RIST will also take some time until market-ready solutions are available. With SRT, introduced in 2017 by Haivision with reference applications as OpenSource, it also took a while until it landed here;-)
SRT knows 3 different connection types
Why Rendezvous Mode is actually not used, you can read here.Why Aren't People Using SRT's Rendezvous Mode?
It is important to understand that the three types of connections have NOTHING to do with the direction of transmission.
RULE: the remote location is always the caller, the studio is always the listener, regardless of whether the outstation is receiving or transmitting a signal.
SRT streams are always progressive.
the following lists are not complete…