Need advice from network nerds

I have a problem I need to solve and need a little guidance. Any help appreciated.

I need a network connection over multi-carrier cellular/LTE/whatever that has carrier diversity. Not bandwidth aggregation, just selecting the best path for traffic based on conditions “right now”.

I have looked at multi-SIM routers but the best I’ve found only has two radios and expen$ive cloud management software.

I am thinking that what I want is a router with a custom Linux build attached to three simple, cheap cellular modems/routers and that can monitor throughput and route traffic based on that and other custom rules like data cost, etc.

Seems to me that a reasonably cheap mainstream router burned with a custom Linux build, some custom software and a few cellular modems could do this… No?

Can anyone give me any guidance here?

How many carriers are you trying to have? How complex are you trying to get with router rules etc. What features are needed etc?

Also, what does the footprint have to be?

Check out these guys
Dual modem and only $500

I did a post about the concept about a month ago.

Bonus Link for finding what carrier you want

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Three carriers (AT&T, Verizon and T-Mobile), footprint doesn’t really matter too much. Router rules needn’t be complex - just route traffic over the “best” route, the primary concern being link speed determined by simple pings.

Google has been working on this for 5 years with Project Fi and it still has issues. It’s a pretty complex problem.

Latency and throughput aren’t the same. Especially in modern networks with traffic shaping and all kinds of shenanigans going on. Can you elaborate on what problem you’re trying to solve? There might be more effective ways of solving whatever problem is at hand.

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I feel I should also clarify even if these were the only concerns before packet loss etc, results will inevitably vary between the destination of the connection as well since different carriers will have different peering and ingress points for the routes. Depending on what exactly the goal is this can be a very hard problem to solve even beyond basic network reliability and packet performance like what Fi is trying to solve.

Be aware that some use

Dual Sim slots similar to an Iphone

They are not “active” modems just in standby such as reaching data limits or roaming.

So AT&T and T-Mobile could share a modem but only one would be in use at a time.

It’s an interesting time right now as I believe we are on the edge of being able to cut landlines and move to wireless so personally if you are looking for a long term solution I would wait for the 5G modems to be released especially if the are you are looking to use in an area that has 5G options.

The one I linked above for example has 4 slots for sim cards


Based on my experience with Fi, their network optimization algorithm was better at de-opimization.


Yes. I’ve seen that. I actually have a three-SIM router but it only has one radio so it’s not going to do what we want to do.

Basically have some stores with craptastic internet connections and want a cellular backup for when it goes down. Boss (well, former boss - I’m in a different area now but doing him a favor) asked me to do some research and I don’t know of a finer bunch of nerds than we have at DMS.

Not super high bandwidth - all web service calls to our network. Could put latency/throughput test endpoints in our web services for monitoring quality.

The ask is definitely for three SIMs and three radios, however that is packaged.

So from this perspective I think the easiest and most managable solution is 3 standard cradlepoints with different carrier’s and a router to do the smarts.

Ebay cisco router suggest the 2901 series with an ehwic card for ethernet ports.

EDIT: Even the MBR1200 would work. Ebay!

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Will that router handle the routing on its own or will we need to push some custom software? Either is fine. Just asking because I’m lazy.

It does the routing on it’s own, I’ll have to dig out my reference on weighting the connections

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Don’t expend too much effort. I am “working” from home and have lots of time.

Check out cisco performance based routing

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Thanks Freddy!