How do you stack and share two broadband lines at home? I've tried dual WAN, single-wire multi-dial, and link aggregation, but the solution I left was the most outdated

my current home network is two broadbands: China Telecom's 500 Mbps is for gaming and work, and China Mobile's 300 Mbps is free with a mobile SIM card. In the year I built the PC, as long as my monthly spending reached 58 yuan, it was free. At first, the mobile one was purely idle, and the light modem was thrown into the weak current box to collect dust. Later, I wondered if the two could be combined to make seven or eight hundred trillion. Just this one thought took half a year of tossing and turning, walking through all four roads, and spending money two or three times unnecessarily. This article will put the conclusion first: the idea of "stacking" two broadbands is something 90% of people can't do in a way that most people imagine, but if you think about it differently, each cable has its own use—much more appealing than stacking.

pour cold water on the question: Why can't single-threaded downloads stack up

This is the one I most want to know in advance, so you don't have the wrong expectations." The so-called 'two 500 Mbps becomes 1000 Mbps' requires downloading software to split the file into many parts, each with different lines. If you open your browser and click a link to download, or use a single-threaded download tool, the task will only follow one line from start to finish. A 500MB port is 500MB, and the other port won't even touch. I downloaded and tested it with IDM running 32 threads: Telecom single-line runs around 520Mbps, and with China Mobile combined, it reaches 780Mbps, which is definitely an increase. But if you switch to a browser and download things directly, it still doesn't budge at all. So first think carefully about your home usage scenario: if several family members watch their own videos and play their own games, the "total bandwidth increase" is a real issue; If you want fast downloads on your own computer, don't expect double the downloads.

there's an even more painful issue: games and live streaming, the two most internet-hungry apps, basically don't get the benefits of stacking. There's only one connection for gaming, and you'll only be on one line. Your telecom line gets 15 milliseconds latency, your mobile cable 35 milliseconds, and the router shifts the game to the mobile one, making you feel 'stacked and sluggish.' This isn't the fault of stacking; it's the load balancing that allocates traffic to the wrong place. Let's explain how to fix it in detail.

I walked through four paths one by one: multi-dial, multi-WAN, aggregation, and a wild approach

the first route is called single-line multi-dial . If you dial several PPP accounts on one broadband, if the operator doesn't block you, you can double the rate. I did this in my rental in 2019: a 100Mbps telecom line dialed three numbers, and downloads really reached 280Mbps. But that's old history; nowadays, most operators have set limits: the number of PPP sessions on the same port is capped, or billed by account. I tried again at home last month. When I dialed the second number, the first one dropped and I couldn't play anymore. Moreover, multiple calls consume the same physical line; if your broadband already has 500 Mbps, even if you dial 800 Mbps, it won't run out, so the effort is wasted. You can basically give up on this path now, unless your local operator is especially lenient.

the second route is a legitimate dual WAN router , with each broadband port dialing its own number, and the router doing load balancing inside. This is the mainstream dual-broadband solution nowadays, and it's the main focus of this article. I'll elaborate on it separately below. The third is called link aggregation , which sounds like it: the router's two ports are bundled together, and the switch side is also tied together, creating 2GB of internal bandwidth. But I advise you to first clarify the target — aggregation solves the speed between intranet devices, such as a computer to a NAS, which cannot control your home outbound broadband. If two broadbands are to be merged through aggregation, the protocol level doesn't work. I spent over 200 yuan on a dual-port aggregation network card back then, but in the end, I plugged it into a NAS and used it. I guess it wasn't worth it. I wrote an article about NAS issues whether to go to a 10-gigabit intranet, and the logic is the same: the internal network is the internal network's business, the export is the export.

The fourth method is the unconventional approach: one computer with two network cards, one connected to a telecom router, the other to a mobile router, and in Windows, the routing table was used to decide who would go there. This trick is suitable for people with only one computer—zero cost, but you can't enjoy it on your phone or TV, and the rules require manual maintenance, which is troublesome. I put it at the end as a backup.

How to choose a dual WAN router

: Don't trust the word "aggregation" on promotional pages

decide to go for dual WAN, choosing a router is the first hurdle. To sum it up in one sentence: see if there's a "multi-WAN port/load balancing" feature, don't be fooled by the "dual broadband acceleration" on the product page. The so-called gaming router I bought for my first phone had a promotional page claiming to support dual WAN, but when I got it, I realized dual WAN is actually 'primary backup'—when one cable breaks, the other is cut off. The mobile one is just standby, and I said how to test speed and never change it. If you really want to do load balancing, soft routers (iKuai and OpenWrt's multi-WAN plugins) are the most reliable. Later, I used an N100 mini host to install iKuai, with two optical modems connected to each network port and a policy router. Some models from ASUS and Netgear support dual-WAN load balancing among finished phones, and TPLINK's enterprise series also has them. Before buying, check the manual PDF to confirm the words "load balancing"—don't just look at the title.

Many people stumble over

wiring: both optical modems need to be switched to bridges, or at least one . If both optical modems are in router mode, your dual WAN router is like having two upper-level routers under it—three layers of NAT. The gaming console is dizzy just looking at it. I've written about NAT type that one, so you know what kind of disaster this is for online setup. I've covered the process of converting optical modems to bridge in this article, for switching optical modems to bridges. There's also a separate article on how to get Telecom's Super Password. After the bridge is modified, each WAN port has its own PPP dial-up—this is the clean structure.

load balancing is unclear, good broadband can become laggy

the real highlight is when dual WAN is paired well: how to divide traffic. There are three ways to categorize AiKuai, and I've tried them one by one, with very different impressions.

default session balance looks fair, but in practice, it creates two problems. First, the games mentioned above are randomly divided; second, IP-sensitive services like online banking and CAPTCHAs can cause trouble: if you log in with a Telecom IP, if you submit a CAPTCHA linked to a mobile IP, the other party sees "a new provincial IP" and immediately kicks you offline. I had run into it before while working remotely at work, dropping every few minutes. After checking all night, I realized it was the Equilibrium Pot. So my final setup was source address binding : TV box, my wife and I phones, game consoles bound to Telecom; Download machine, monitor upload, visitor WiFi binding to mobile. This way, the purpose of each cable is clear, no one robs the other, and online banking never drops again. Additionally, several latency-sensitive domains (game platforms, remote desktops) are separately written with policy routing to enforce telecom routes, providing double protection.

another detail: both lines in iKuaili must be paired with the ISP's DNS or public DNS—not one with 223.5.5.5 and one with 114. Otherwise, some apps will switch between service nodes, and video apps will frequently switch to CDN, making it look like an unstable network. I've made mistakes about DNS beforeDNS I wrote an article the web page is slow if the configuration isn't right. You can check it.

Move 300MB free cable, this is the best value

you will find that the value of dual broadband is not in "stacking 800 Mbps," but in two lines doing two types of . My current division of labor: all the "latency-sensitive" things on the 500 Mbps telecom network—gaming, video calls, remote work; All the 'running volume, no latency' features of the Mobile 300 Megatube — NAS remote backup, monitoring video uploaded to the cloud, downloading movies from the device, and smart home networking. With this point, the latency on Telecom's cable is much more stable, and even during evening rush hour, there's no congestion because all the dirty and tiring work of high data is done by Mobile itself. For more information about the surveillance line, you can see my article about installing surveillance cameras home surveillance network planning, and the upload volume is quite a lot.

add three bonus gameplay options. First, moving-level disaster recovery : Last year, during a typhoon, the telecom line was blown out for half an hour, and FamilyMart automatically switched to Mobile. The children's online classes were not affected. This was the most practical moment of dual broadband. Second, visitor dedicated line : all guests are connected to the visitor WiFi via mobile cables, so the main network devices and bandwidth are not affected at all. How to isolate them? I wrote the same approach in my article Tenant Network Setup. Third, indifferent : switching the default router to another router when restarting or changing configurations, the whole family doesn't notice, and after that, they switch back again. This kind of ease is something broadband users will never experience.

Copying according to budget: Three gameplay styles to match your needs

final direct conclusion for those who don't have the patience to read the whole story. The first scenario: both broadband lines are legitimately paid and want to get it fast: buy a router or N100 soft router that supports dual WAN load balancing, convert the two optical modems into bridges, bind source addresses, increase total bandwidth, and keep single-threading as single-line. The second is the free card application (most commonly given by China Mobile/Unicom): don't mess with the balance—just focus on primary backup or manual division of labor. The free device is dedicated to downloading, monitoring, and visiting, keeping the main line clean. This is the best value for money. The third is that if you want to use two cables on one computer: two network cards connected to two routers, with routing tables, or you can use multithreaded download tools like IDM to split threads and run two cables, with zero device cost.

my complete detours for your reference: first try to make multiple dials (already dead), buy the wrong primary and backup router (200 yuan tuition), then switch to a soft router with session balance (online banking disconnected), and finally bind to the source address for a comfortable experience. If someone had told me back then, 'Stacking is fake need, division of labor is the real value,' and those three payments could save two of them. The order can be summarized in one sentence: first confirm whether the requirement is total bandwidth or single-threaded speed. The former uses dual WAN for gigabit routing, while the latter is discouraged; Two optical modems converted to bridge; Balancing policies should bind source addresses rather than default sessions; Latency-sensitive domains are set up with separate policies; The cable I gave was focused on the dirty work. Following this order, the dual broadband issue is handled in one go.