It Really Is a Series of Tubes: Surviving BGP Leaks, 95th-Percentile Transit, and Backhoes in seriesoftub.es

Back in 2006, U.S. Senator Ted Stevens accidentally gave networking engineers their favorite meme of all time when he explained that the internet “is not a big truck—it’s a series of tubes.”

Twenty years later, Series of Tubes (seriesoftub.es)—an open-source browser game created by Fabian Jäckel (fjaeckel/seriesoftubes)—takes that quote literally and turns it into what is essentially SimCity or OpenTTD for ISPISPInternet Service ProviderNetworkingAn organization that provides residential, enterprise, or carrier network connectivity, IP transit, and routing access to the global Internet. and network engineers.

At first glance, the cartoon world map and cheerful UI make it look like a casual idle game. Five minutes later, your primary terrestrial fiber trunk has been severed by a stray backhoe, a shark is chewing on your transoceanic subsea cable, your 95th-percentile upstream transit bill is bleeding your bank account dry, and a DDoSDDoSDistributed Denial of ServiceSecurityA coordinated attack in which multiple systems flood a target network, router, or server with traffic to exhaust bandwidth or compute capacity. attack is melting your core router in Frankfurt.

It is a remarkably fun—and brutally challenging—simulation of how the physical internet actually works.

---

From One Router in One City to Tier 1

You start the game at the bottom of the internet food chain: a tiny local ISP with a single router in a single Point of Presence (PoPPoPPoint of PresenceNetworkingA physical network facility or colocation site where routers, switches, and optical transport equipment aggregate and interconnect traffic between networks.), zero peering relationships, and 100% reliance on expensive upstream IP Transit to reach the rest of the world.

Your goal is to scale that single box into a transit-free Tier 1 carrier spanning global capitals. Getting there forces you to juggle the exact same economic and engineering trade-offs that real network operators sweat over every day:

---

Why It’s So Deceptively Hard

If you play seriesoftub.es the way you play a standard tycoon game—expanding as fast as possible and signing every customer contract that pops up—you will go bankrupt almost immediately.

Here is where the game’s teeth show up:

1. The 95th-Percentile Transit Trap vs. IXP Peering

When you sign up residential broadband customers (“eyeballs”) or enterprise networks early on, every megabit they pull from the outside world has to cross your upstream transit provider, billed on the 95th percentile. If you don’t aggressively join Internet Exchange Points (IXPsIXPInternet Exchange PointNetworkingPhysical switching infrastructure where ISPs, CDNs, and networks interconnect directly to exchange traffic via BGP peering without upstream transit fees.), peer with route servers, and haul traffic across your own dark fiber to cities where content actually lives, your transit bill grows faster than your customer revenue.

2. Not All Bandwidth Is Created Equal

As you grow, you unlock wildly different customer tiers:

• Home broadband (“eyeballs”): Steady, predictable residential traffic.
• High-Frequency Traders (HFTHFTHigh-Frequency TradingNetworkingAlgorithmic financial trading systems engineered around ultra-low-latency optical paths, kernel-bypass networking, and FPGA hardware to execute orders in microseconds.): They don’t care about bulk throughput—they care about lowest possible latency across the shortest physical fiber path between financial hubs.
• Hyperscaler DCIDCIData Center InterconnectNetworkingHigh-speed, low-latency optical networking that links multiple data centers together to replicate storage, share traffic, or interconnect compute clusters. & AIAIArtificial IntelligenceAIComputer systems and neural architectures capable of reasoning, code synthesis, pattern recognition, and autonomous agentic execution. GPUGPUGraphics Processing UnitHardwareA massively parallel processor originally designed for 3D rendering and now critical for accelerating AI model training, LLM inference, and video transcoding. Data Centers: Massive elephant flows that look great on a revenue sheet right up until a single contract saturates your router line cards and DWDMDWDMDense Wavelength Division MultiplexingNetworkingOptical fiber multiplexing technology that transmits multiple high-capacity data channels simultaneously over a single fiber pair using distinct wavelengths of light. optics, causing packet loss across every other customer sharing that backbone link.

3. Backhoes, Sharks, and the Myth of “80% Utilization”

In a textbook, running a link at 80% utilization looks efficient. In seriesoftub.es (and in production networking), running two parallel links at 80% utilization means you have zero redundancy—because the moment a backhoe slices Link A, 160% of the traffic tries to fail over onto Link B, instantly dropping packets and tanking your SLASLAService Level AgreementReliabilityA contractual commitment establishing formal service availability, latency targets, and remedies between a service provider and customer. reputation.

And the game does not hold back on physical and routing chaos:

• Terrestrial fiber cuts from construction backhoes knocking out overland links.
• Subsea cable faults (including sharks) severing intercontinental routes across the Atlantic or Pacific.
• BGPBGPBorder Gateway ProtocolNetworkingThe exterior gateway routing protocol that manages how packets are routed across autonomous systems (AS) forming the backbone of the Internet. route leaks and RPKIRPKIResource Public Key InfrastructureSecurityA cryptographic security framework that binds IP address prefixes to their authorized Autonomous System Numbers (ASNs) to prevent BGP route hijacks and leaks. mishaps where a peering session suddenly dumps unexpected traffic onto your network.
• Volumetric DDoS attacks that test whether you left enough switching capacity and scrubbing headroom at the edge.

---

The Best Kind of Systems Sandbox

Playing seriesoftub.es makes invisible infrastructure immediate and tactile. You stop thinking of “the cloud” as an abstract APIAPIApplication Programming InterfaceDevOpsA formal contract of endpoints, protocols, and data schemas that enables distinct software services to exchange commands and state predictably. endpoint and start seeing it for what it really is: undersea glass fibers, optical transceivers, IXP switching fabrics, BGP announcements, and a constant race to build a ring topology before the next backhoe finds your trench.

If you have half an hour to spare—and want to see if you can make it to Tier 1 without getting bankrupted by transit fees or a cut transatlantic cable—give seriesoftub.es a spin. Just don’t blame me when it’s 1:00 AM and you are still optimizing optical line cards between Tokyo, London, and Ashburn.