SRFLX candidate of Erizo?


#1

Hello Licode team,

I tried to deploy coturn and Erizo Agent (pre-v5.1) on GCP. All servers were on the same subnet. When trying to force TURN relay, I found out that the candidate type was “relay”, not “prflx”. With “relay” type, Erizo transfers data to coturn server with coturn’s public IP, which will be an additional egress cost on GCP.

I noticed that Erizo only gathered “host” candidates, and ErizoJS replaced private IP with public IP in the candidate strings. As a result, what the client side received were “host” candidates with public IP. That’s why the candidate pair of coturn server and Erizo is always “relay”.

Does Erizo support “srflx” candidates, and return “host” and “srflx” candidates to clients? If yes, how can I enable this feature? Thanks in advance.

Regards,
GuangDe Lin


#2

Answer: stun server must be specified to gather SRFLX candidates.

Assign config.erizo.stunserver and config.erizo.stunport with stun.l.google.com:19302, and everything works fine.