The CSG300 series is a family of compact Versa Cloud Services Gateway appliances – the CSG350, CSG355, and CSG365 – built to deliver secure site-to-site SD-WAN connectivity to small branches and home offices. All three run the Versa Operating System (VOS) and support optional LTE and Wi-Fi modules; the CSG355 and CSG365 add next-generation firewall and UTM security.
Key takeaways
- The CSG300 series spans three models: CSG350, CSG355, and CSG365.
- CSG350 targets small branches up to 75 users; no built-in security tier.
- CSG355 and CSG365 add NGFW and UTM for small-to-medium branches.
- All models support optional dual-LTE and Wi-Fi modules for site links.
- Desktop mount on the CSG350; desktop or 19-inch rack on CSG355/CSG365.
On this page: Why it mattersHow it worksCSG300 series modelsCSG300 series & the VersaONE platformFAQ
Why is the CSG300 series important?
Small branches and home offices are the hardest sites to justify specialist hardware for: there’s no on-site engineer, limited space, and no budget for a rack of boxes. The CSG300 series exists to bring the same SD-WAN, security, and centrally managed policy that larger sites get down to a single compact, often desktop-mounted appliance – without asking a two-person satellite office or a remote worker’s home to look any different, operationally, from a headquarters site.
Because every CSG300 model runs VOS, the same design that governs a data-center-scale Cloud Services Gateway applies unchanged here – only throughput, port count, and security tier differ. That consistency matters most at this end of the family, where an organization can least afford a management plane that behaves differently from the rest of the network. Optional LTE and Wi-Fi modules let the same chassis serve as the site’s sole connectivity and access point.
What is the CSG300 series?
A CSG300 series appliance is an aluminum-chassis, fan-cooled gateway with four Gigabit Ethernet ports (six on the CSG355 and CSG365), a serial console port, and a USB 2.0 management port. Front-panel status and power LEDs report appliance health; rear-panel LEDs cover Controller connectivity plus wireless and LTE module state. Two nano-SIM slots on the rear panel support single- or dual-LTE deployments, and PoE source support is available on four Ethernet ports with an add-on NIC module.
The CSG350 is the smallest of the three, with two built-in wireless slots and 32 GB of storage; it mounts on a desktop only. The CSG355 and CSG365 share an identical, larger chassis with two LTE slots plus one dedicated Wi-Fi slot, and can mount on a desktop or in a 19-inch rack. Deployment follows the standard site model: the appliance terminates WAN circuits (Ethernet, LTE, or both), builds encrypted SD-WAN paths to the headend, and – on the CSG355 and CSG365 – enforces next-generation firewall and UTM policy inline.
CSG300 series models
The three models are sized by branch capacity and security tier. CSG350 is the compact, cost-optimized model for small branches up to 75 users needing hierarchical QoS and application/cloud-intelligent SD-WAN, with 32 GB of storage and no built-in NGFW/UTM tier. CSG355 adds advanced SD-Security – NGFW and UTM – to the same small-to-medium branch profile, also with 32 GB of storage. CSG365 is the highest-performance model in the series, pairing the same NGFW/UTM security with 64 GB of storage for medium-sized branch locations. SKUs encode the model, wireless module configuration (single/dual LTE, Wi-Fi, region), and NIC type (general-purpose Ethernet, T1/E1, or xDSL) in a single part number. For full connection and mounting steps, see Connect a CSG300 Series Appliance.
CSG300 series & the VersaONE platform
Like every Cloud Services Gateway, a CSG300 series appliance runs VOS and is provisioned and managed from Versa Director or Concerto – the appliance ships in factory state, reaches the headend on first boot, and pulls its site configuration through zero-touch provisioning. Configuration and monitoring are also available from the appliance CLI over the serial console or SSH, though Versa recommends managing the device from Director or Concerto rather than locally. The CSG300 Series Hardware Guide documents the full specification set: chassis dimensions, power and environmental limits, regulatory compliance, and export control classification for each model.
Frequently asked questions
What’s the difference between the CSG350 and the CSG355/CSG365?
The CSG350 is the compact, entry model for small branches with no built-in NGFW/UTM tier. The CSG355 and CSG365 share a larger, identical chassis and add next-generation firewall and UTM security; the CSG365 further doubles storage to 64 GB for higher-demand medium branches.
Can a CSG300 series appliance run without a wired WAN connection?
Yes. Each model supports optional embedded LTE modules – up to dual-LTE via two nano-SIM slots – plus a USB port for an LTE dongle, so a site can run on cellular WAN alone or combine it with Ethernet and Wi-Fi links.
Can the CSG355 and CSG365 be rack-mounted?
Yes. Unlike the desktop-only CSG350, the CSG355 and CSG365 chassis include integrated rack-mount ears and can be installed in a standard 19-inch, four-post rack in addition to desktop placement. Mounting takes two people using the M4 and M6 screws shipped with the appliance; the CSG350 remains desktop-only regardless of site preference.
How does a CSG300 series appliance get its configuration?
Through zero-touch provisioning: the appliance ships in factory-default state, connects to the Versa headend on first boot, and pulls the full site configuration bound to it from Director or Concerto templates, without requiring an on-site engineering visit.
What management access does a CSG300 series appliance support?
A dedicated RJ45 serial console port and a copper Gigabit Ethernet dual-purpose data/management port provide local CLI access for monitoring and troubleshooting, though day-to-day configuration is intended to run through Director or Concerto rather than the CLI directly.
More on Versa hardware
If you want to learn more, these are sources we trust.
| Versa Networks: products | Versa Networks: secure SD-WAN | Versa Academy |
|---|---|---|
| The vendor’s product pages, including the CSG appliance families and their positioning. | The SD-WAN service the CSG300 series delivers at small branches and home offices. | Training and labs that cover Cloud Services Gateway deployment hands-on. |
Related terms
If you’re reading about the CSG300 series, these are worth looking at next.
| Cloud Services Gateway | Network Interface Card | Branch |
|---|---|---|
| The full Versa appliance family, from CSG150 through CSG5000, that the CSG300 series belongs to. | The field-installable module that adds Ethernet, PoE, or DSL ports to a CSG300 appliance beyond its built-in ports. | The kind of site a CSG300 series appliance is sized to serve: a small branch or home office. |