The Surface Problem: Which Sierra Wireless AirLink Do You Order?
The question I hear most is procurement pressure in a technical costume: Should I choose the Sierra Wireless AirLink MG90 or the AirLink MP70? Sometimes the caller is equipping an ambulance fleet. Sometimes it's a mobile health pilot that has to go live before a grant deadline. And sometimes they have the VSRX product page open too, hoping a third option will make the answer obvious.
I've been in that position. In my role coordinating field connectivity for EMS, mobile health, and utility clients, I've handled more than 200 time-sensitive deployments. The pattern is almost always the same: a deadline moved, a new vehicle arrived, or a pilot was already booked, and someone needs a router decision by Friday.
The honest answer is that you're not trying to pick a router. You're trying to solve a network problem before it costs you an operational deadline. Those are very different questions.
Sierra Wireless AirLink MG90 vs MP70: Specs Are Only the Top Layer
According to Sierra Wireless public product documentation (sierrawireless.com, accessed January 2025), the AirLink MG90 is positioned as a next-generation 5G gateway with Wi-Fi 6, while the AirLink MP70 is positioned as an LTE-Advanced Pro vehicle router. Those are real differences. They're also the least useful part of a decision, because they're the only part the product page can tell you.
It took me about six years and far too many late-night troubleshooting calls to understand that a router is not a network. It's a node. The most expensive mistake in field communications is replacing the node and expecting the network around it to improve.
A router can be the most reliable device in the vehicle while the network around it is exactly what continues to fail. That sounds like a contradiction. It isn't.
The Deeper Problem: A Router Is Not the Network Chain
A cellular connection is a chain. The gateway is the visible part at the vehicle end, but the same chain includes antenna placement, cable loss, SIM profile, APN, carrier routing, power stability, firewall policy, and remote management. When one link is misconfigured or mechanically weak, the symptom usually looks like a router problem. It usually isn't.
In March 2024, 36 hours before a mobile health go-live, a customer asked us to prepare replacement Sierra Wireless AirLink MG90 units because the current units kept failing an upload test. We didn't replace the gateways. We changed the SIM profile from the default consumer APN to a dedicated M2M APN from the carrier. The gateway was never the problem. The configuration was.
A few months later, in July 2024, I was asked to fix an AirLink MP70 that kept dropping data sessions in a new rescue vehicle. The radio module was healthy. The problem was the antenna, mounted inside a rear equipment bay a few centimeters from a steel shelf. We moved the antenna to the roof, replaced two RF cables, and the same MP70 held a session for the entire test route. Nothing about the product page changed.
The same blind spot shows up in an even less dramatic example. Put a blood pressure monitor in a mobile clinic and let it send readings over Wi-Fi to the vehicle gateway. If that session drops for a few minutes, a clinician simply takes another reading. No ticket is opened, no root cause is found, and the loss disappears. It doesn't feel like an emergency, but it's the same network problem that, in a mission-critical moment, will interfere with a transmission you can't retake.
The Real Cost: False Confirmation
Silent network problems are the hardest to fund, because they don't generate an obvious bill. Then someone on the operational side checks the network with a clear phone call. The call goes through, the voice sounds fine, and the case is closed. That's not a pointless test, but it's incomplete.
A clear phone call verifies one thing: a clear phone call. It doesn't verify uplink data, authentication, packet loss, or the end-to-end path between the blood pressure monitor and the server. When an emergency deployment is on the line, that distinction isn't academic. It's the difference between finding a problem before it becomes an incident and finding it after. I've watched teams lose a full day to this false confirmation.
What to Do Instead of Opening Another Product Page
If you're reading this with the VSRX product page open, close it for a minute. That page doesn't know where the antenna will be mounted, which APN the SIM will use, or who's responsible when the vehicle is in a coverage gap. No product page can answer those questions.
- Start with the transaction that can't fail. Is it a live video session, a periodic blood pressure monitor reading, a dispatcher message, or a telemetry stream? Let that transaction drive the requirements, not the fastest possible speed test.
- Walk the physical path before you write the PO. Look at the vehicle or cabinet. Ask where the antenna will live, how the cables will run, and what metal sits between the radio and the tower.
- Test with the real endpoint. Don't test with a speed test app. Run the actual data session, including the device application, while the vehicle is moving.
- Demand remote visibility before rollout. If the device can't be monitored remotely, your first warning will be a phone call after the fact. In emergency deployments, that warning is too expensive.
Should that router be the AirLink MG90? For a new deployment where 5G, Wi-Fi 6, and a longer life cycle are part of the plan, it's a reasonable choice. Should you rip out an AirLink MP70 that's already working? Not just because a newer spec sheet exists. If the antenna, APN, and monitoring issues aren't solved first, the newest gateway will fail in the same way, and the real problem will stay hidden.
No product page ever told me where to mount an antenna. Field knowledge did. It's usually the part that saves the deadline.
So before you make the router decision, ask the question that actually matters: where is the weak link in the chain? The router is probably not it. When you fix the right layer, the Sierra Wireless device you choose will start to look a lot more reliable. It was reliable all along.