One request leaves a flat in Accra. This page follows it and shows where the cost starts.
A viewer presses play. The request crosses the last mile and reaches the access network of the ISP. It then reaches the border router, the machine that decides how traffic leaves the building. That router has two kinds of exit port. The two ports do not cost the same.
One port goes to a local internet exchange, a shared switch where networks trade traffic directly. Accra has three of them. GIXA opened in 2013 and holds about two dozen networks. Accra-IX opened in 2023 and now carries the most capacity. LINX Accra opened in 2025.
Traffic that crosses an exchange to a peer is settlement-free, which means that neither network pays the other. The ISP pays for the port and the cross-connect. The ISP pays nothing for each megabit.
An exchange holds no content of its own. It is a switch in a neutral building, and each member runs a fiber into it. One ISP cannot take video from the appliance of another ISP. Netflix sets each appliance to answer only the addresses that its host ISP announces to it. What an ISP does reach across the exchange is the equipment of the content network itself. Netflix, Google, Akamai and Cloudflare all place servers at exchanges for this reason.
Most of what crosses an exchange is not content. It is traffic addressed to the customers of another member. Examples are a phone call, a bank interface, or a page hosted in Ghana. Before local exchanges existed, that traffic went to Europe and came back. Two people in the same city sent packets across two continents. Each ISP decided that its international link cost less than a separate link to every other ISP.
The Internet Society measured this effect in Kenya and Nigeria. Domestic round trips fell from 200 to 600 ms down to less than 10 ms. Nigeria then grew from 300 Mbit/s of local traffic to 125 Gbit/s. The saving on international transit rose to about $40 million each year.
So the exchange is not a place to look for content. It is a place where every member becomes free to reach. This is why the absence of Netflix costs money. Traffic from Google and Meta reaches an Accra viewer through the free port. Traffic from Netflix reaches the same viewer through the metered port.
The other port goes to a transit provider, a network that sells access to the rest of the internet. This port is metered. Each network announces its prefixes, which are the blocks of addresses that it owns. If the border router did not learn the prefixes of Netflix from a local exchange, it has nowhere else to send the packets. They take the default route out through the paid port, down a submarine cable, to Europe.
| destination | learned from | exit port | marginal cost |
|---|---|---|---|
| 102.176.0.0/12 local ISPs | GIXA route server | ix-port | settlement-free |
| 157.240.0.0/16 AS32934 Meta | Accra-IX | ix-port | settlement-free |
| 142.250.0.0/15 AS15169 Google | GIXA | ix-port | settlement-free |
| 23.246.0.0/18 AS2906 Netflix | no local exchange | transit-port | billed per Mbps |
| 0.0.0.0/0 default | upstream transit | transit-port | billed per Mbps |
The dot goes out with the request and comes back with the video. Every number on the diagram is a round trip, so the dot spends half of it in each direction. The pause at London is the origin that builds the response. The dot moves at a speed that matches real time, so the slow part is the submarine cable. The return leg carries the video, and the transit bill is measured on that direction. Both routes use the same horizontal scale, and the second route stops early.
The prefixes and the times for each hop are examples. The exchanges, cables and landing points are real. Google and Akamai peer at GIXA, Fastly peers at Accra-IX, and Meta peers at all three. If a network is absent from the exchange that your ISP joined, you must buy transit to reach it.
Fig. 1 gives the submarine hop 65 ms. Every other hop costs less than 10 ms. The cause is not congestion.
The cable does not go where the map suggests. It follows the West African coast through a line of landing points. The fiber laid between two of those points is longer than the line between them.
The place of each exchange also matters. An exchange helps only a network that holds a port at it.
The transit port charges for each megabit per second. The provider measures the traffic at the ninety-fifth percentile of the month, which ignores only the busiest 5 percent of it. Video at peak hour is the worst traffic to buy transit for. It is large, it lasts for hours, and it arrives in the same window that sets the bill.
An Open Connect appliance is a cache server that Netflix ships to a qualified ISP at no charge. A cache server keeps a copy of the content near the viewer. The appliance draws less than 750 W and connects over two to six 10 GbE ports. It holds the part of the catalog that the region watches. After the ISP installs it, peak Netflix traffic never touches an external link.
The appliance is also not a proxy. It never fetches a title at the moment a viewer asks for it. It holds what the overnight fill gave it. Netflix serves anything else from another site over peering or transit.
The appliance fills overnight, when the transit link is idle and does not set the bill. Netflix requires a steady peak of at least 5 Gbit/s before it will place an embedded appliance. Under that level, the ISP can only peer. Peering helps only if Netflix is present on an exchange that the ISP joined.
The solid line is the SAT-3 cable through its real landing points. The dashed line is the straight path from Accra to Portugal. Count the crossbars on the cable. Five of them fall before Portugal, on a trip the straight line measures at 3,800 km. The route runs 1.3 times the straight line.
A filled bar means this ISP holds a port at the exchanges in that city. Accra is the only such city. One bar stands for a city, not a count. Accra runs three exchanges and Lagos runs two, and the count does not change the port question. NAPAfrica in Johannesburg holds more than 380 networks and charges nothing to peer. It sits 4,700 km from Accra, and London sits 5,100 km away.
Peak Netflix traffic 8.0 Gbit/s
Transit $2.00 per Mbps / month
Netflix publishes the 5 Gbit/s level, the 750 W draw and the port configuration. The times are examples. They come from about 10 ms of round trip for each 1,000 km of route. You set the transit price. A 100 GigE port in a hub such as London reached about $0.05 for each Mbps in 2025. Markets that depend on long-haul capacity to reach that hub pay several times more.
The appliance is not a favor in either direction. The ISP bought transit to carry the same few thousand titles across the Atlantic every evening. Netflix paid for its own viewers to get a worse picture than the viewers of its competitors, at the hour that mattered most. One box, one hop earlier, removes both costs. The expensive part was never the content. The expensive part was the port that the content left through.