Each cloud instance type has limits on packets per second and bandwidth, and traffic over them is silently dropped.
Why Rising CCU pushes packets per second over the instance limit → Effect The cloud network drops the excess → On screen Teleporting and skills not going off from unexplained packet loss. Server CPU has headroom
Primary owner Infra team (Server infrastructure) · Also Game team (Server development), External (External)
Game team action items
Combine packets (one tick’s messages in one packet), avoid sending tiny packets frequently.
Infra team action items
Check and alert on limit-exceeded counters (pps_allowance_exceeded, conntrack_allowance_exceeded, and so on for AWS), move to a larger instance, avoid connection tracking limits with a security group setup that creates no tracking.
External action items
Ask the cloud provider for packets-per-second and connection tracking limits per instance type.
Ballpark numbers
Limits differ by instance size, and the packets-per-second limit is often not published. The “up to 10 Gbps” on small instances is a burst speed available only while credits last (usually 5–60 minutes); the normal baseline speed is much lower.
On the graph
Hits a ceiling · Packets per second, allowance exceeded counters
Where to look
Collect the ENA counters pps_allowance_exceeded, bw_in_allowance_exceeded, bw_out_allowance_exceeded, and conntrack_allowance_exceeded from ethtool -S at short intervals and view them alongside packets per second. You can also publish these counters with the CloudWatch agent and set alarms on them
Confirmed if
Allowance exceeded counters rise at the times of loss, and packets per second stops climbing at a fixed value. Server CPU has headroom
Ruled out if
Exceeded counters flat: not this cause. One core’s %soft at 100%: “NIC interrupts concentrated on one core”
Check with
Infra tools (no game code needed)
Learn more
conntrack_allowance_exceeded means the connection tracking table was full and new connections were dropped. If the table has room and only idle connections drop because their tracking expired, see the “Cloud security group connection tracking expiry” entry.
Amazon EC2 instance network bandwidthAWS The “up to N Gbps” of instances with 16 vCPUs or fewer is a burst that spends network I/O credits (usually 5–60 minutes), falling back to baseline bandwidth when the credits run out