Riot Explains the Technicalities Behind Artificial Latency at MSI 2022
Riot spoke about why it chose to conduct MSI 2022 on artificial ping
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Riot Games published a tech-focused blog written by the Riot Esports Technology Group and League of Legends Engineering, on 17th May, explaining the details of the much-discussed artificial latency used at the Mid-Season Invitational (MSI) 2022.
The competitive integrity of the MSI 2022 has arguably been the hottest topic of the tournament, ever since Riot announced that the League of Legends Pro League (LPL) representative – Royal Never Give Up (RNG) – would be participating remotely from China because of COVID-19 restrictions.
Following this, all the teams at the LAN were forced to play the tournament on an artificially hiked latency of 35 ms to match the latency in Shanghai, China, from where RNG is competing from. However, on 13th May, Riot Games revealed it found discrepancies with the latency at the MSI, which affected the teams playing from Busan, Korea.
Due to the discrepancy, RNG, which was unaffected by the technical error, was made to replay its first three games to ensure fairness and uphold the competitive integrity of the tournament.
Through the blogpost, the company has now revealed how the artificial latency tool works and why it failed at the start of the tournament.
“Over the last several days, the Riot Esports Tech Team has been working through a set of technical issues surrounding a tool we are using to equalize the ping values between our local and remote competitors for the Mid-Season Invitational 2022 (MSI) event,” stated the blog.
Why didn’t Riot Games catch the bug sooner?
Riot Games stated that it found a bug in the Latency Service Tool, which was configured to adjust the latency (ping) to 35 ms for all players competing in the event. “The reason we did not find it sooner is that the cause of the issue was a code bug that miscalculated latency, which meant that the values in our logs were also wrong. As a result, our ongoing monitoring and pre-event testing showed everything was working correctly, even though it was not,” it clarified.
As a result, following a reconfiguration on 13th May, the issue was addressed and Group B games were remade. However, a side effect of this fix was a “visual issue where the ping displayed on players’ screens in Busan was incorrect as it was lower than the actual, corrected ping.”
When a player’s screen was broadcasted, the incorrect, lower-than-intended ping (only visually) was seen and Riot had not communicated this visual discrepancy. Now, this led to viewers believing that players in the LAN were playing on a ping lower than 35 ms.
What were Riot’s options to make MSI 2022 work?
Riot Games stated that it was presented with COVID-19-related challenges and had to work around RNG’s curfew situation. It said that the problem was that Busan and Shanghai are approximately 850 km away with a sea running between them and that the latency clocked in at 35 ms.
Riot further mentioned that it considered remote play for RNG because, for League of Legends Esports, a ceiling of 40 ms is considered viable at the highest competitive level with an acceptable variance of +/- 5 ms. Riot ruled out RNG alone playing on 35 ms since it would not be fair for the Chinese representatives.
Its second option was to put the servers halfway between China and Korea to have 17.5 ms for everyone but this would mean that the servers would have to be relocated to the middle of the ocean. Its third and only working option was to introduce artificial latency, the blog said.
It turns out that the League Dev Team already has a way to introduce artificial latency, known as the Latency Service. Some refer to it as “fake ping.” This is a client/server feature that was built to address the need to level the playing field for remote competition due to COVID-19 travel restrictions. The Latency Service allows us to set a target (say 35 ms ping), and it injects delay on the client and server for each player as needed to equalize everyone at that same level of latency."Riot Games
Riot pointed out that even though it had used this before for fully remote events, this would be the first instance where it was using it for a global event with teams also playing from LAN.
The tech team apologized for the “disruption and frustration caused during the tournament” and said it is continuing to monitor the remainder of the tournament to keep it running smoothly.
