On Thursday evening the calls started again. Readers told Prothom Alo that both broadband and 4G had slowed; tests between 9 and 10 pm showed 3 to 6 Mbps on mobile networks that should give 30. This time there was independent data. Cloudflare Radar, which measures internet performance country by country, showed Bangladesh below 20 Mbps all day on 1 August, and below 7–8 Mbps for most of it.
What the ISPs said
Emdadul Haque, president of the ISP Association of Bangladesh, gave two reasons late on Thursday night. The first is ordinary: “traffic is higher after evening”, and a network already running near its limit slows when everyone comes home. The second is the one BTRC gave on Monday: the Google and Meta cache servers inside the country were switched off during the shutdown and are still pulling fresh copies of everything over the international links, which is bandwidth that users would otherwise have. He expected the caches to need another 24 hours and the network to be normal by Friday. For the record, the timeline: mobile internet cut on the night of 17 July, broadband at 9 pm on 18 July, limited broadband back on the night of 23 July, 4G at 3 pm on 28 July.
How to check for yourself
A slow evening can be the country, your operator, or the router under the TV. Three tools separate them.
- fast.com — open it on the phone or laptop; it shows download speed in a few seconds with no ads or button. It measures from Netflix’s servers, which are cached inside Bangladesh, so a low number here means the problem is local: your operator or your Wi-Fi. Test on mobile data and on Wi-Fi separately.
- Cloudflare Radar — go to radar.cloudflare.com, choose Bangladesh, and look at the traffic and quality graphs for the last 24 hours. If the national line has dropped, it is not your router. Radar is also the site that showed, hour by hour, the shutdown itself.
- Speedtest by Ookla — pick a server abroad (Singapore is the usual choice) and compare with a Dhaka server. If Dhaka is fine and Singapore is slow, the bottleneck is the international link — the cache-refill story — and there is nothing to fix at home.
The two-minute rule
Before blaming anyone: restart the router, stand next to it, run fast.com, then run it on mobile data. If both are slow and Radar shows the country down, wait. If only Wi-Fi is slow, it is the router or the ISP’s local line, and the ISP’s helpline is the right call. If only mobile is slow, it is the tower — the operators were still restoring capacity a week after the shutdown. None of this will be needed once the caches are full. It is worth knowing anyway; the next slowdown will not come with an explanation.
What a speed test cannot tell you
One limitation worth knowing before you draw conclusions from a number. A speed test measures the path to the nearest test server, which is often inside your own operator’s network or at a local exchange — so it can report 40 Mbps while a video call to Dubai stutters, because the congestion is on the international route the test never touched.
For calls and meetings, the numbers that matter are latency and packet loss, not bandwidth. Any speed test shows ping; above about 150 ms, conversation becomes awkward regardless of speed, and loss above one or two per cent is what makes voices break up. A 5 Mbps line with low loss carries a video call better than a 50 Mbps line that drops packets.
