Inconsistent Packet Routing to MPS Servers?

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Beth Leuenberger asked May 13, '24

Inconsistent Packet Routing to MPS Servers?

Hi! (apparently tilda crosses out, so here it is again, apologies for the triple post)

We use PlayFab MPS for hosting servers for a 1v1 / 2v2 fighting game, as well as matchmaking / general backend etc. Broadly MPS has been very effective for us so far and straightforward to use!

However we had a public beta late last month with approx. 10k participants and had an issue crop up with certain players where their pings to certain playfab regions were much higher than expected. IE. Players located in the Los Angeles area who had pings of 150+ to West Us and West Us 2 beacons (and to the servers as well if they forced matchmaking to only place them there). The issue was persistent and lasted the whole beta weekend, and in certain players cases functionally prevented them from playing online as they had extremely high pings to all available server regions, despite being located near them.

After some investigation, if affected players used something like https://visualtraceroute.net/ to see the route their game packets were taking we noticed that their packets were being routed very oddly (ie LA to West Us, going from LA to the midwest, then to San Jose) and then back to the server / beacon.

For the player in the above image, they have Google Fiber in LA, and were able to use a VPN they have through their work to play at expected pings (<20-30 to West Us), so definitely seems like something with their ISP just routing packets to PlayFab very poorly. However it wasn't specific to ie just Google Fiber in LA, and affected people in Phoenix / Seattle / West Canada and some people in the upper midwest / Minnesota area, etc.

If that's the case, is there anything we can do to help resolve this issue for players? It wasn't widespread but it more or less prevented the affected players (approx 50) from playing in ideal conditions and didn't resolve throughout the beta weekend. It seemed to be primarily affecting the West and Central US server regions, as we had no reports from players close to East servers encountering the issue.

Additionally, we've been noticing a similar issue for players who have 'normal' pings to servers, where when connected to a server their ping to that server suddenly inflates to about double of their normal value (ie 60 to 120), (40 to 80-90 etc), and does perform the way you would expect with that inflated ping. It can remain that way for around 15-30 minutes and doesn't affect everyone connected to that server. It's weird because while experiencing the inflated udp latency you can ICMP ping / tracert the server ip and get normal values, but if you udp ping the QoS beacon you get the same value the game is reporting.

I'm unsure if this is related to the regional routing issue but feels at least of a kind to me, and would be curious if anyone knows what may be causing / what could be done about it?

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Answer 1 · 2024-05-13T10:04:45Z

Xiao Zha answered May 13, '24

There are many factors that affect latency, including location from the playfab server and network conditions, even the server load. In order to obtain a low-latency connection, you need to ensure the Quality-of-Service (QoS) of the servers is sufficient to support your gameplay. We would suggest you evaluate the QoS of different Azure regions to determine which has the lowest latency. You can refer to our documentation: https://docs.microsoft.com/en-us/gaming/playfab/features/multiplayer/servers/using-qos-beacons-to-measure-player-latency-to-azure .

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Beth Leuenberger commented · May 13 at 10:39 PM

We utilize QoS beacons to evaluate many different azure regions, as I described in the post. We had servers up in all of the supported Azure US regions, and used the QoS beacons to determine the player's ping to them. The issue is the packets to the beacons were being routed very poorly, again as I described, and if the player connected to a server in one of those regions, their ping reflected the poor routing as well.

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Xiao Zha Beth Leuenberger commented · May 14 at 09:59 AM

Sorry for inconvenience. Since you mentioned that packets are being routed in a strange way, resulting in high latency, the issue may be related to the network conditions of these players and the ISPs they use. For this, PlayFab has no good way to reduce latency. Players could try switching to a different network. Or as you mentioned above, to use a VPN to reduce latency.

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