Your SIMs, on your own network.
Not a tunnel you maintain. Not a subnet we hand you. Your SIMs terminate on your network, take their addresses from your systems, and behave like anything else you own. A device on a rooftop three counties away sits on the same network as the machine under your desk.
Underneath: Layer 2 handover over L2TP. Our mobile core acts as the LAC, your L2TP network server terminates the session, and your RADIUS decides which SIMs get on and what addressing they receive. IPv4 and IPv6, across a pool of SIMs you define.
This has always been a wholesale arrangement.
Layer 2 handover is how mobile operators sell to large enterprises and other carriers. It takes a commercial agreement, a volume commitment and somebody at the operator to configure it. It is not something you order.
We have made it a setting. Define a pool of SIMs, point them at your L2TP server, and they arrive on your network authenticated by your systems. There is no minimum, which means the same arrangement a national retailer would negotiate is available to one person with a router in a cupboard.
A developer can put a SIM on their home network alongside the NAS. A small manufacturer can bring field equipment onto the office LAN without buying a leased line. As far as we know, nobody else offers this at this scale.
The network decisions become yours.
This is the difference between choosing from options we offer and running the thing yourself.
Your RADIUS decides
Authentication happens against your systems. You decide which SIMs are allowed onto the network at all, using the same infrastructure that already authorises everything else you run.
Your addressing
Addresses come from your pools, IPv4 or IPv6, assigned by your systems at session setup. Not a range allocated to you, your actual addressing plan.
Your existing tools
Monitoring, DNS, firewalling, access control. Everything already pointed at your network now covers the cellular estate too, with nothing new to learn or licence.
How the session is handed over
Standard L2TP, the way carriers have done wholesale handover for decades. Nothing proprietary and nothing you have to take on trust.
Your equipment
Router, gateway or module with a SIMSY SIM
SIMSY core
Initiates the L2TP session for SIMs in your defined pool
Your side
Terminates the session, authenticates the SIM, assigns the address
L2TPv2 carries PPP, which is point to point. Each SIM has its own session to your LNS. This is not a shared Ethernet broadcast domain, so SIMs do not ARP for each other across it. SIMSY LAN is the product for device-to-device reachability; see section below for when to pick which.
What you need at your end
Something to terminate the L2TP session. That is a smaller requirement than it sounds, and there are two routes.
A router that speaks L2TP
Plenty do, including the InHand routers we sell from around £150. Point it at our LAC, set your addressing, done. If you already run something capable at the edge of your network, you probably do not need to buy anything.
Software on a machine you have
An L2TP network server runs happily on ordinary hardware. If you would rather terminate on a server, a VM or something small already sitting on your network, that works too.
SIMSY Extend or SIMSY LAN?
These sound similar and are not. The difference is whose network the devices end up on.
We give you a network
Your SIMs join a private subnet inside our core, where they can reach each other directly. Nothing at your end is required at all.
- Nothing to run, nothing to terminate
- Devices talk to each other, wherever they are
- Right when the traffic that matters is machine to machine
You already have a network
Your SIMs join the network you already run, authenticated by your systems and addressed from your pools. You terminate the session at your end.
- Needs an L2TP server, in hardware or software
- Devices become part of your existing estate
- Right when you want one network, not two
Six ways teams use it
Home labs and prototypes
A SIM on your home network alongside everything else, reachable by hostname, behind your own firewall and DNS. Build against real cellular without a separate environment.
Field equipment on the corporate LAN
Remote assets treated as ordinary internal devices, covered by the same monitoring, patching and access control as anything on site.
Replacing leased lines
Sites that need to be on the network properly, without the cost or the lead time of fixed circuits.
Regulated estates
Where authentication and addressing have to be under your control and evidenced by your systems rather than a supplier’s.
Existing NAC and segmentation
Cellular devices subject to the same network access control and segmentation policy you already enforce internally.
IPv6 deployments
Native IPv6 addressing from your own allocation, rather than working around what a provider offers.
Put a SIM on your own network.
Whether that network is a data centre or a cupboard under the stairs, the arrangement is the same one and there is no minimum to reach first.