Quick definitions
| LAN | WAN | |
|---|---|---|
| Scope | Single building or campus | Across cities, countries, the whole internet |
| You own it? | Yes — cabling, switches, Wi-Fi APs | No — leased from a telco |
| Typical speed | 1–10 Gbps wired, 1–5 Gbps Wi-Fi 6/7 | 100 Mbps – 10 Gbps per site |
| Typical latency | < 1 ms | 1–300+ ms depending on distance |
| Main tech | Ethernet, Wi-Fi (802.11) | Fibre internet, MPLS, SD-WAN, mobile 4G/5G |
| Who fixes it? | You (or your integrator) | Your telecom provider |
What's a LAN?
A LAN — Local Area Network — is the network inside one physical location. If you're in your office and you can reach a printer, a colleague's laptop, or a file server without going through the internet, you're using the LAN.
Almost every business LAN today is built from the same building blocks:
- Structured cabling. The Cat6 (or Cat6A, or fibre) cables that run from each desk and access point back to the comms cupboard. Installed once, expected to last 10–15 years. See our structured cabling guide for how to scope a project.
- Ethernet switches. The boxes in the comms cupboard that all the cables plug into. They forward traffic between devices on the LAN at wire speed (1 Gbps or 10 Gbps per port is now standard). Common vendors: Cisco, Aruba (HPE), Juniper, Ruckus, Ubiquiti, Huawei.
- Wi-Fi access points (APs). Mounted on the ceiling, plugged into the switches by a single cable that also powers them (Power over Ethernet, PoE). Modern offices use Wi-Fi 6 (802.11ax) or Wi-Fi 7 (802.11be). See The Modern Wireless Stack for the trade-offs.
- A router / firewall. Sits at the boundary between the LAN and the WAN. Decides which traffic can leave, which can enter, and where it goes.
The classic LAN protocol is Ethernet (IEEE 802.3) for wired connections and Wi-Fi (IEEE 802.11) for wireless. Both run on top of IP (Internet Protocol), which is what gives every device an address (e.g. 192.168.1.42) so it can be reached.
What's a WAN?
A WAN — Wide Area Network — connects multiple locations together and out to the wider internet. You don't build a WAN yourself; you lease the underlying lines from a telco. In Singapore that's most commonly Singtel, StarHub, M1, MyRepublic, NTT, or one of the regional carriers (Tata, NTT, Telstra) for international links.
"The internet" is itself just one giant WAN — a global mesh of thousands of provider networks (ISPs) that have agreed to carry each other's traffic. When you "connect to the internet," you're really connecting your LAN to your telco's WAN, which in turn connects to other telcos' WANs.
How they connect: the router as the border
The boundary between LAN and WAN is your router — sometimes a standalone appliance, sometimes built into the modem your telco shipped you, sometimes a serious enterprise firewall (Fortinet, Palo Alto, Cisco). Three jobs:
- Translate addresses. Devices on your LAN have private IPs (192.168.x.x or 10.x.x.x) that can't be reached from the internet. The router uses Network Address Translation (NAT) to swap them for your single public IP on the way out, and remember which response goes back to which device.
- Filter traffic. The firewall function — block anything malicious or unwanted from coming in, restrict which destinations users can reach on the way out.
- Route. Decide which interface every packet should leave on. Important if you have multiple internet lines (one fibre + one backup), or if some traffic should go via a private link to another office instead of the internet.
WAN flavours: Internet, MPLS, SD-WAN
There are three common ways to build a business WAN. Most companies above ~10 sites use a mix.
Plain internet (with VPN)
Each site gets a fibre internet line. If you need site-to-site connectivity, you build VPN tunnels (IPsec) over the internet between the routers. Cheap, flexible, easy to set up, but performance varies with internet congestion — and there's no quality-of-service (QoS) guarantee for sensitive traffic like voice.
MPLS (Multiprotocol Label Switching)
A private network service from a telco that connects your sites directly to each other without traversing the public internet. Highly predictable performance (low latency, low jitter, guaranteed bandwidth), excellent for voice and real-time apps, expensive and slow to provision. Standard for banks, hospitals, and large enterprises. Many MPLS networks in Singapore are run by Singtel, StarHub, and NTT.
SD-WAN (Software-Defined WAN)
The middle ground — and the dominant new deployment pattern. Each site gets two or three cheap broadband / fibre lines from different providers, plus a small SD-WAN appliance. The appliance continuously measures the performance of each link and steers each application down whichever path is best right now. Often paired with cloud-hosted security (SASE) so users get the same protection on every link. Vendors: Cisco Meraki, Fortinet, VMware (VeloCloud), HPE Aruba (Silver Peak), Palo Alto (Prisma).
The Singapore picture
Singapore is unusually well-served on the WAN side. The Nationwide Broadband Network (NBN) means every commercial address has access to 1 Gbps fibre, with 10 Gbps available at moderate cost. International connectivity is exceptional thanks to a dense web of submarine cables landing in Tuas, Changi, and on the south coast — see Global Connectivity for the bigger picture.
Three practical implications:
- Cheap, fast last-mile. A 1 Gbps business fibre line is widely available for a few hundred dollars a month — far cheaper than equivalent capacity in most other Asian cities.
- Easy redundancy. Because multiple telcos can deliver fibre to most addresses, getting a second line from a different carrier is straightforward — important for sites that can't tolerate downtime.
- Cross-border WAN is well-priced. Singapore is the regional hub for most APAC corporate networks, so MPLS and Ethernet circuits to other major cities (KL, Bangkok, Jakarta, Sydney, Tokyo) are competitively priced compared with running them from elsewhere.
Bandwidth, latency, jitter, packet loss
Four numbers describe network performance. All four matter; "speed" alone doesn't.
- Bandwidth (Mbps / Gbps) — the maximum throughput. Like the diameter of a pipe. Easy to advertise, easy to test, often the only number a sales rep talks about.
- Latency (ms) — how long a single packet takes to make a round trip. Within Singapore: 1–5 ms. Singapore to Hong Kong: ~35 ms. Singapore to London: ~160 ms. Critical for interactive applications (video calls, remote desktop, online games, financial trading).
- Jitter (ms) — variation in latency. A steady 50 ms is fine for a voice call; bouncing between 20 ms and 200 ms ruins it. Voice and video need low jitter more than they need huge bandwidth.
- Packet loss (%) — what fraction of packets never arrive. Anything above 1% causes noticeable problems on real-time apps.
A "10 Gbps" link with high jitter and 2% packet loss is worse for voice and video than a "100 Mbps" link with rock-steady performance. Insist on SLA commitments on all four metrics, not just bandwidth.
What to pay attention to when buying
Where to go next
Two natural next steps depending on your interest:
- Wireless deep-dive: The Modern Wireless Stack — Wi-Fi 6/7, 5G, and LoRa compared. Next step in the Networking Foundations path.
- Global picture: Global Connectivity: Submarine Cables, IXPs, and BGP — what happens once a packet leaves your office.
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