MikroTik CSS318-16G-2S+IN 16-Port Gigabit SwOS Switch

The MikroTik CSS318-16G-2S+IN solves a specific port count problem that is common in small and medium network deployments: 8-port switches run out of capacity too quickly as the network grows, and 24-port switches waste rack space, power, and budget when only 12–18 devices need wired connectivity. The CSS318 sits precisely between these two options — 16 Gigabit Ethernet ports for downstream devices and 2 SFP+ 10G uplink ports for upstream connectivity, in a 10-inch form factor that fits where standard 19-inch switches do not.

The 10-inch form factor is the defining physical characteristic. Standard 19-inch rack switches are designed for full-size equipment cabinets — they are oversized for wall-mount enclosures, desktop deployments, small server closets, and the compact rack spaces common in SME offices, retail locations, hospitality environments, and home network installations. The CSS318 fits a 10-inch rack natively — the correct form factor for compact wall-mount enclosures, under-desk rack shelves, and small rack units where a full 19-inch switch physically does not fit. When a standard 19-inch rack is the installation environment, two CSS318 units mount side by side in a single 1U 19-inch rack space — 32 Gigabit Ethernet ports and 4 SFP+ 10G uplinks in one rack unit, with independent management per unit. For growing networks where port count is expected to expand, the two-units-per-1U architecture provides a scalable, cost-effective path to 32-port capacity without purchasing a 24-port or 48-port switch upfront.

The 2 SFP+ ports support both SFP+ 10G modules and standard SFP 1G modules — the uplink speed scales from 1G to 10G depending on the SFP module installed. For a network where the uplink today is 1G (connected to a 1G router or upstream switch) but 10G uplink is planned when the upstream infrastructure is upgraded, the CSS318's SFP+ ports accommodate both speeds without replacing the switch. SFP module compatibility should be confirmed with your MikroTik distributor — MikroTik supports its own S+module series (S+RJ10, S+85DLC03D, S+31DLC10D) in SFP+ ports and specific third-party SFP modules. The SYNOXX SFP and SFP+ transceiver range in your catalogue should be confirmed for CSS318 compatibility.

SwOS is the management operating system — MikroTik's switch-focused web-based management platform, the same platform used on the FTC21 media converter. SwOS provides the full managed switch feature set appropriate for small and medium network deployments:

- **Port-to-port forwarding** — configure which ports can communicate directly, isolating traffic as required

- **Broadcast storm control** — limit broadcast traffic on ports to prevent broadcast storms from degrading network performance — critical in environments with many connected devices

- **MAC filtering** — permit or deny specific MAC addresses on specific ports — Layer 2 access control without requiring a full firewall

- **VLAN configuration** — IEEE 802.1Q VLAN tagging and port-based VLAN segmentation — isolate guest Wi-Fi traffic, VoIP traffic, management traffic, and data traffic on separate VLANs across the same physical switch

- **Traffic mirroring** — mirror traffic from one port to another for network monitoring, IDS/IPS, and troubleshooting — allows a network analyser to observe traffic from any port without in-line interception

- **Bandwidth limitation** — per-port bandwidth limits — enforce download and upload speed limits on individual switch ports — useful for shared office environments or hospitality deployments where per-device fairness is required

- **Adjustment of MAC and IP header fields** — advanced header manipulation at the switch level — relevant for service provider and VLAN retagging deployments

The SwOS web interface is browser-accessible — no proprietary client software required, no Winbox installation necessary. For IT staff and network administrators who manage the switch occasionally rather than daily, the browser-based interface reduces the software management overhead.

The Marvell 98DX2518 switch chip is a Gigabit multi-port switch ASIC with hardware-accelerated VLAN, QoS, ACL, and switching — all forwarding decisions are made in hardware at line rate across all 16 Gigabit and 2 SFP+ ports simultaneously. There is no CPU-bound forwarding bottleneck — the switch operates at full wire speed under maximum load on all ports.

Power consumption is 10W without attachments and 13W under full load with all ports active — among the lowest power draws for a 16-port managed Gigabit switch with 10G SFP+ uplinks at this price point. Passive cooling (no fan) means no fan noise — relevant for office environments, home installations, and any location where fan noise from network equipment is unacceptable. The passive cooling design also eliminates fan failure as a maintenance concern — the CSS318 runs continuously with no moving-part failure modes.

MTBF of ~200,000 hours at 25°C is the highest MTBF tier published in the MikroTik catalogue — consistent with the cAP LTE12 ax, Chateau LTE18 ax, NetBox 5 ax, and FTC21 in this product batch. For a switch that runs continuously and unattended in a wall closet or rack, the ~200,000 hour MTBF means the device is statistically expected to run for approximately 22.8 years before first failure at 25°C ambient — a meaningful reliability indicator for a buy-and-forget infrastructure device.

The -40°C to +70°C operating temperature range covers all standard indoor Canadian installation environments including unheated server closets and equipment rooms in cold climates. For outdoor or semi-outdoor enclosure installations, confirm that the IP20 rating (indoor, no moisture protection) is appropriate for the installation environment — the CSS318 is not weatherproof and requires a fully enclosed, moisture-controlled installation space.

Software updates are included for the life of the product or a minimum of 5 years from the date of purchase — consistent with MikroTik's standard software update commitment across the product line.

Key specifications:

- **Switch chip:** Marvell 98DX2518

- **OS:** SwOS

- **Ethernet ports:** 16× 10/100/1000 Mbps Gigabit Ethernet

- **SFP+ ports:** 2× SFP+ (10G / 1G compatible)

- **Storage:** 16 MB FLASH

- **AC input:** 100–240V, 50–60 Hz

- **Max power consumption:** 13W (with attachments), 10W (without)

- **Cooling:** Passive

- **IP rating:** IP20 (indoor installation only)

- **CPU temperature monitor:** Yes

- **Operating temperature:** -40°C to +70°C

- **MTBF:** ~200,000 hours at 25°C

- **Certifications:** CE, EAC, RoHS — no FCC, no IC published

- **Included:** IEC cord, screw set (4), CSS rack ears

- **Form factor:** 10-inch (also fits 19-inch rack — two units per 1U)

- **Product code:** CSS318-16G-2S+IN

Note: SFP/SFP+ modules not included — confirm compatible module type and speed with your MikroTik distributor before purchase. CPU architecture and RAM are not published on the product page — confirm from brochure if required for procurement documentation.