Summary

An NTTN (Nationwide Telecommunication Transmission Network) is a licensed entity in Bangladesh authorized to build, maintain, and lease the physical fiber-optic infrastructure across the country. ISPs and mobile operators rent “dark fiber” or capacity from NTTNs to transport data between cities and neighborhoods.

Overview

Before the NTTN license was created, every ISP and mobile operator tried to lay their own fiber cables, leading to a messy “spiderweb” of overhead wires and frequent road digging. To solve this, the BTRC introduced the NTTN license to centralize the construction of a nationwide fiber backbone.

Summary

An Internet Exchange Point (IXP) is a physical location where different Internet Service Providers (ISPs), Content Delivery Networks (CDNs), and large networks connect to exchange internet traffic locally. By keeping data within the local infrastructure, IXPs reduce latency, improve speeds, and lower the cost of international bandwidth.

Overview

Internet traffic can be broadly divided into two categories:

1. International Traffic: Data that must travel to servers outside the country (e.g., accessing a website hosted in the USA).
2. Local Traffic: Data shared between two users or servers within the same country.

Without an IXP, if a user on ISP-A in Dhaka sends an email to a user on ISP-B in Chittagong, the data might travel through international undersea cables to Singapore or Europe before coming back to Bangladesh. An IXP allows ISP-A and ISP-B to connect directly, ensuring the data never leaves the country.

Summary

In Bangladesh, ISPs often market “Total Speed” (BDIX + International), which can be misleading. If your Facebook and YouTube are fast but your downloads from global sites are slow, you are likely experiencing the gap between your Local (BDIX) and International bandwidth limits.

Overview

Bandwidth is not a single “pipe.” For a user in Bangladesh, it is split into:

1. Local Traffic (BDIX): Accessing servers inside Bangladesh (FTP, local newspapers, government sites).
2. Cache Traffic: Accessing Google (YouTube/Play Store) and Meta (Facebook/WhatsApp/Instagram) through local caches.
3. International Traffic: Accessing the “real” global internet (Twitter/X, Reddit, Microsoft, GitHub, Zoom).

Technical Deep-Dive

ISPs buy international bandwidth in “Mbps.” This is expensive. To make packages look attractive, they “burst” your speed for cached and local content while keeping a strict limit on everything else.

Summary

Slow Wi-Fi is often separate from your actual internet speed. In Bangladesh, the most common causes are thick concrete walls, interference from neighboring routers in crowded cities like Dhaka, and poor router placement.

Overview

It is important to understand the difference between Internet Speed (what your ISP provides) and Wi-Fi Speed (how fast your device talks to your router). You might have a 50 Mbps connection, but if your Wi-Fi signal is weak, you will only experience a fraction of that speed.

Summary

An IIG (International Internet Gateway) is a licensed intermediary in Bangladesh that acts as a bridge between local Internet Service Providers (ISPs) and the international internet. IIGs aggregate traffic from ISPs and route it through submarine cables ( BSCPLC ) or overland terrestrial cables ( ITC ).

Overview

In the Bangladesh internet hierarchy, the IIG sits in the middle:

1. The Source: BSCPLC (Submarine) or ITC (Terrestrial cables from India).
2. The Wholesaler (IIG): Companies like Fiber@Home, Summit Communications, or Amber IT.
3. The Retailer (ISP): Your local provider (e.g., Link3, Dot Internet, or a neighborhood ISP).
4. The Consumer: You.

Without an IIG, a local ISP would not have the legal or technical means to access global websites like Google, Facebook, or Amazon.

Summary

An ONU (Optical Network Unit) is a device used in fiber-optic internet (FTTH) that converts optical signals (light) into electrical signals (Ethernet) that your computer or router can understand. It is the endpoint of the ISP’s fiber network at your home or office.

Overview

If you have a fiber-optic connection, the cable coming into your house is made of glass. Since your router cannot “read” light, it needs a translator. The ONU sits between the fiber cable and your router.

Summary

BDIX (Bangladesh Dhaka Internet Exchange) is the first and largest local Internet Exchange Point (IXP) in Bangladesh. Established in 2014, it is a non-profit organization that allows local Internet Service Providers (ISPs) to exchange traffic within the country rather than sending it through international submarine cables, resulting in significantly faster speeds and lower latency for local content.

Overview

When you access a website or service located in Bangladesh (like a local newspaper, bank, or FTP server), the data doesn’t need to travel to Singapore or the USA and back. BDIX provides a physical meeting point where different ISPs connect their networks. This “local peering” keeps domestic traffic inside Bangladesh, which is cheaper and much faster than using international bandwidth.

Bridge Mode: Using Your Own Router with an ISP ONU

Summary

Bridge Mode is a configuration that turns your ISP-provided ONU (Optical Network Unit) into a simple “bridge” that passes the internet signal directly to your own router. This allows your personal router to handle all networking tasks, eliminating “Double NAT” and improving Wi-Fi performance.

Overview

Most ISPs in Bangladesh provide a “2-in-1” device that acts as both an ONU and a Wi-Fi router. However, these devices are often basic and lack advanced features like QoS, VPN support, or strong Wi-Fi coverage. Bridge Mode allows you to use a more powerful router (like a Mikrotik, Asus, or high-end TP-Link) as the “brain” of your network while the ISP device simply acts as a fiber-to-ethernet converter.

DNS Caching: Why Old Website Addresses Get Stuck

Summary

DNS Caching is a process where your computer, router, or ISP saves the IP address of a website you’ve visited so that it doesn’t have to “ask” for it again. While this makes browsing faster, it can cause problems if a website moves to a new server and your cache is still pointing to the old, broken address.

Overview

Think of DNS caching like a contacts list on your phone. If your friend changes their phone number but you don’t update your contacts, you will keep calling the old, wrong number. Similarly, if a website’s IP address changes, your device may continue to use the “stale” cached IP until the timer (TTL) expires or you manually clear the cache.

DNS Comparison: Cloudflare vs. Google vs. ISP DNS

Summary

Choosing the right DNS provider can significantly improve your browsing speed, privacy, and ability to bypass local network issues. While your ISP provides a DNS by default, switching to a global provider like Cloudflare (1.1.1.1) or Google (8.8.8.8) is often a better choice for users in Bangladesh.

Comparison Table

Technical Deep-Dive

1. Cloudflare (1.1.1.1)

Cloudflare is currently the world’s fastest DNS. They have a Point of Presence (PoP) in Dhaka, meaning your queries are resolved locally rather than traveling to Singapore. They also support advanced privacy features like DoH and DoT.