Teleporting: 47 causes and who fixes them

Also called: warping, skipping, freeze then jump

A character moves to a distant spot in one step, with no movement in between.

Another player stands still, then suddenly appears far away, where they had already moved.

It usually means packets stopped arriving for a while. Check for packet loss, brief connection drops, server stalls, and extrapolation failures. If one player jumps around while everyone else is fine, suspect that player’s connection first.

Causes of this symptom

L1 Client game process

Excessive extrapolation (dead reckoning): While no packets arrive, the client keeps showing characters moving at their last velocity, then snaps them back when it turns out to be wrong. (Game team (Client development))

L2 Client OS and device

Receive buffer overflow: If the game is busy and pulls packets out of the socket (the network send/receive interface the OS provides) late, the OS buffer overflows. (Game team (Client development))
Wi-Fi background scanning: Communication pauses briefly while the OS periodically hops across channels to look for nearby Wi-Fi networks. (External (External))

L3 Home network

Wi-Fi interference and weak signal: With a weak signal or interference, packets get resent several times over the wireless link, so they arrive unevenly. (External (External))
Bufferbloat (router queue): When someone in the household uploads a video or downloads a large file, hundreds of ms worth of packets pile up in the router’s queue, and game packets wait behind them. (External (External))
Cell tower handover (while moving): When you travel by bus or subway, the connection drops out while your phone switches cell towers. (External (External))
Weak mobile signal and dead zones: In elevators, basements, and deep inside buildings, retransmissions increase, speed drops, and eventually the connection drops. (External (External))
Frequent 5G↔LTE switching (at 5G coverage edges): Inside buildings with weak 5G signal or at the edge of 5G coverage, the phone switches between 5G and LTE often, and each switch causes a ping spike or a brief dropout. (External (External))

L4 Internet path

Satellite internet (LEO/GEO): Satellite signals have to travel to space and back. With geostationary satellites the round trip alone exceeds 0.5 seconds. Low Earth orbit satellites such as Starlink are usually fast, but latency fluctuates and the link can drop briefly at the moment routes are reassigned. (External (External))
Peak-hour congestion at peering links: Around 9–11 PM, video traffic surges and the links between ISPs (peering) tend to get congested. (Infra team (Network infrastructure))
Submarine cable / international link outage: When a submarine cable is cut, traffic takes long detours for weeks (sometimes months) until it is repaired, and the remaining links get congested. (External (External))
BGP route changes and convergence: When internet routing information changes, packets are lost for the few seconds to tens of seconds (rarely a few minutes) it takes to converge again. (Infra team (Network infrastructure))
One faulty ECMP path: ISPs and data centers keep several paths to the same destination and send each connection down one of them. If a single path fails, only the players assigned to it keep lagging. (Infra team (Network infrastructure))
ISP throttling and traffic management: When you go over your data allowance, or on plans that manage certain kinds of traffic, packets get delayed or dropped. (External (External))
Country- or ISP-level UDP restrictions and packet inspection: Some networks block specific UDP addresses and ports or throttle UDP, and packet inspection equipment filters out protocols it doesn’t recognize. Games that communicate over UDP can’t connect on those networks or disconnect often. (External (External))
Poor line quality: Loose connectors, old wiring, or a faulty modem cause steady packet loss and periodic line drops. (External (External))
Shared links saturated by DDoS: Massive attacks aimed at the game company, or at someone else on the same network, fill up shared links. (Infra team (Network infrastructure))
Routing through a VPN or game booster: With a VPN or game booster on, packets go through that company’s relay servers. If the relay is far away or busy, the connection can actually get slower. (External (External))

L5 Data center network equipment

DDoS protection detours and false positives: Diverting traffic to a scrubbing center to stop attacks makes the route longer, and legitimate players are sometimes mistaken for attackers and blocked. (Infra team (Network infrastructure))
Switch microbursts: When several servers send packets to thousands of players at the same instant, the small buffer on the switch port where that traffic converges overflows in less than 1 ms. (Game team (Server development))
Data center link saturation: When patch distribution, log shipping, or backups share a link with the game, the link fills up. (Infra team (Network infrastructure))
Bad cables and port errors: Bad optics or a bad cable corrupt a steady share of the packets that pass through that path. (Infra team (Network infrastructure))

L6 Server network card

NIC interrupts concentrated on one core: If the NIC sends every packet-arrival interrupt to a single CPU core, that core becomes the bottleneck. (Infra team (Server infrastructure))
Ring buffer too small: If the NIC’s ring buffer, which briefly holds incoming packets, is small, a sudden burst overflows it and packets get dropped. (Infra team (Server infrastructure))
Cloud PPS limit exceeded: Each cloud instance type has limits on packets per second and bandwidth, and traffic over them is silently dropped. (Infra team (Server infrastructure))
NIC bandwidth saturation: Running a 1 Gbps or 10 Gbps card at its limit makes the transmit queue grow until packets get dropped. (Game team (Server development))
Cloud host maintenance and live migration: When a cloud provider performs maintenance on a physical server (host), it moves VMs to another host (live migration) or pauses them briefly. The whole server freezes during that time, and if the pause is long, connections drop. (Infra team (Server infrastructure))

L7 Server OS (kernel)

Kernel socket buffers too small: With small send and receive buffers, a burst of traffic makes the kernel drop packets arriving over UDP, and TCP sends block because the buffer has no room left. (Infra team (Server infrastructure))
Server conntrack table full: When the connection tracking (conntrack) table, where the Linux firewall records every connection, reaches its limit, new packets are dropped. (Infra team (Server infrastructure))

L8 Sockets and protocols

Slow client (slow consumer) handling policy: When a client’s outgoing data keeps piling up, the server drops stale updates or disconnects it. (Game team (Server development))
IP fragmentation of UDP packets: A UDP packet larger than the MTU (the largest size that can be sent in one piece) is fragmented at the IP layer, and losing just one fragment throws away the whole packet. (Game team (Server development))

L9 Server game process

Broadcast fan-out overload: Sending one player’s movement to everyone who can see them creates updates on the order of the square of the crowd size. (Game team (Server development))
Patch changes the traffic pattern: When new content, effects, or synced fields raise packet size and frequency, a server that ran fine starts hitting MTU, bandwidth, and packet-rate limits after the patch. (Game team (Server development))

Netcode design

Client authority: When each client decides its own results, your own screen feels responsive, but results disagree with other players’ screens and the game is easy to hack. (Game team (Server development))
Rollback netcode misprediction: The game predicts the opponent’s input and shows it early, then rewinds and recomputes if the guess was wrong. The higher the ping, the further it rewinds. (Game team (Client development))
Pathfinding mismatch in command sync: When only “go here” is exchanged and each side computes the path itself, even a small difference in the calculation sends a character or monster down a different path until it gets pulled back into place. (Game team (Server development))
Low snapshot send rate: If the server sends position updates (snapshots) only a few times a second, the interpolation buffer has to be that much longer, and you see other characters further in the past. (Game team (Server development))

Problems only some players hit

A lagging player moves in bursts on others’ screens: Inputs from a player with a bad connection reach the server unevenly, in bunches. If the server applies whatever arrived on each tick, other players see that character hitch and then cover several steps at once. (Game team (Server development))
A lagging client controls the monster: Some games hand monster movement to one nearby player’s client to reduce server load. If that player’s connection is bad, the monster moves strangely on everyone’s screen. (Game team (Server development))
Lost baseline snapshot: When the server sends “only what changed since last time,” losing the full state sent once at the start (the baseline) means later changes can’t be applied. (Game team (Server development))

Root causes of TCP retransmission

Wireless link loss: Wi-Fi and mobile networks retransmit a few times on the wireless link and drop the packet if that still fails. TCP resends the dropped packet only much later. (External (External))
Send bursts overflow shallow buffers: When a server sends a whole tick of updates for thousands of players in one instant, a switch’s small buffer or a cloud instance’s short-term limit overflows in under 1 ms and some packets are dropped. (Game team (Server development))
Policer drops excess traffic: ISP plans, cloud instance limits, and DDoS protection devices sometimes drop packets over a set rate right away, without queuing them. (Infra team (Network infrastructure))
Physical errors (bad cable, optics, connectors): Damaged cables, dirty fiber connectors, and worn-out optics cause bit errors, and network equipment silently drops the corrupted packets. (Infra team (Network infrastructure))
Packet drops on the receiving host: Packets reach the server but get dropped, because the NIC’s ring buffer (which briefly holds arriving packets) overflows or the kernel cores that handle receive processing are saturated. (Infra team (Server infrastructure))
Middlebox over capacity (firewall, IPS, DDoS protection): Firewalls, intrusion prevention systems (IPS), and DDoS protection devices inspect every packet passing through. The moment traffic exceeds their inspection capacity, they drop the packets they can’t process. (Infra team (Network infrastructure))
Route change / bad ECMP path: Packets vanish for a few seconds while an internet route changes, or steadily on connections assigned to a faulty path among several ECMP paths. (Infra team (Network infrastructure))

View the illustrated symptom guide