2x 4g modems - load balancing

Thinking about getting another 4g modem/sim. What would be the cheapest way to load balance them together so I can increase my speeds?

https://amzn.to/2oVnnRM £175 for a dual WAN load balancing router.

There is stuff a lot cheaper but throughput issues become an issue i.e. cheaper is slower CPU/less memory.

If you have an old PC then a linux distro to do the load balancing/routing so long as it has two network cards would be the cheapest

Make sure you understand the limitations of simple load balancing.

If for example if you have two 4G connections topping out at 20mb/s each, load balancing them won't give you a 40mb/s connection.

The sort of load balancing that is available by simply combining two 4G connections happens at the TCP connection (or UDP port) level, so you'll be able to download/stream two different things at 20mb/s, but you won't be able to download/stream a single thing at 40mb/s.

And correct me if I'm wrong but wouldn't they both be eating the bandwidth of the same cell tower? Which in itself could be a limiting factor?

I use a Draytek 3220 (Quad WAN), can be had cheap off ebay, think I paid under £200 for mine.
I use 3 x mobile connections, 2 are unlimited 1 is 100Gb limit.
Session based load balancing will in all but single thread activity (which is basically very little eg a Website will open many sessions) combine the speeds of all connections.

Its not bonding, but its as close as you can get. Most other dual WAN routers use sticky sessions in so much that it will keep a PC or device on the same WAN.

The draytek also "learns" the limit of each connection and adjusts its balancing, this changes many times throughout the day.

https://www.draytek.com/solutions/load-balancing/ - gives all the details.

Good routing policy config also which is a bonus.

There are other dual WAN drayteks probably even cheaper on ebay also and they are all roughly the same setup.

Edited by Rolandrat (Fri 08-Nov-19 14:43:06)

In reply to a post by buggerlugs:

And correct me if I'm wrong but wouldn't they both be eating the bandwidth of the same cell tower? Which in itself could be a limiting factor?

Yes, it is not worth using two SIMs from the same network, and this is where you want to avoid the virtual networks that are on the same host as your first SIM. (e.g. giffgaff is on O2, and TESCO is also on O2).

That depends on the modem/router.

I can "see" three Three towers from my house. I use an Mikrotik router with a built-in high gain antenna, with it tight against the wall facing one of the towers it can only "see" that one tower.

If I wanted more bandwidth via Three I could install another of these high gain routers pointed at one of the other towers.

Luckily the 60-80 down and 30 up that I get from a single connection is enough for my needs...

wow! 3x Three cell towers! You are lucky, I'm like 2km from the single one in my entire area, which probably explains why I'm only getting a 3rd of what you do the vast majority of the time.

I�m 1.5km from the tower I use, the ground is completely flat though and there are few houses. The other two are a fair bit further.

I�m live in a village that also has 3 cell sites. From my house I can move the router around and connect to either of the three. However three have set their network up so that only one cell is worth connecting to as one is band 20 and the other has a narrow �beam� so you have to be exact when routing router.