MikroTik CRS504-4XQ-OUT 4×100G QSFP28 IP66 Switch

The MikroTik CRS504-4XQ-OUT is the outdoor counterpart to the CRS504-4XQ-IN — the same Marvell 98DX4310 Prestera switching ASIC and 4× 100G QSFP28 port architecture, rebuilt in a sealed IP66 weatherproof enclosure for permanent outdoor installation at tower sites, rooftop aggregation points, outdoor venues, and any location where 100G switching capability must live outside the equipment room. At USD 899.00, it is the most cost-effective outdoor 100G switching platform in the current MikroTik catalogue — and the only 100G switch in the MikroTik lineup rated IP66.

**The 98DX4310 Prestera — the same switch ASIC as the indoor CRS510-8XS-2XQ-IN**

The Marvell 98DX4310 is the same switch chip documented for the CRS510-8XS-2XQ-IN in this product batch. In the CRS504-4XQ-OUT, the 98DX4310 drives four 100G QSFP28 ports — its full switching capacity directed at four high-bandwidth interfaces rather than the CRS510's eight 25G + two 100G port mix. The capabilities are identical: hardware-offloaded Layer 2 switching at line rate, hardware ACL, MLAG, jumbo frame support, and L3 hardware offloading for inter-VLAN routing on established flows. The outdoor enclosure does not compromise the switching silicon — the 98DX4310 operates identically in the IP66 enclosure as in the indoor 1U rack chassis.

The 98DX4310's internal architecture is the key to the CRS504-4XQ-OUT's port flexibility: each QSFP28 port is connected to four 25G lanes in the switch chip fabric. This four-lane-per-port architecture is what enables QSFP28 breakout operation — a single QSFP28 port's four internal 25G lanes can be exposed as four independent 25G SFP28 connections via a QSFP28-to-4×SFP28 breakout cable. MikroTik's own product description states this directly: "each port is connected to four 25 Gigabit lines — that means you're getting up to 16 high-speed fiber interfaces from a single outdoor switch."

**The 4× QSFP28 port backward compatibility matrix — full flexibility in a single outdoor switch**

Each of the four QSFP28 ports on the CRS504-4XQ-OUT supports multiple operating modes simultaneously across the four ports:

- **100G (100GBASE-SR4, 100GBASE-LR4, 100G QSFP28 DAC/AOC):** Native 100G operation — connecting to another 100G device: a CRS510-8XS-2XQ-IN, CRS518-16XS-2XQ-IN, a second CRS504-4XQ-OUT at a remote tower, a 100G router (CCR2004 with 100G interface), or a service provider's 100G handoff point.

- **40G (40GBASE-SR4, 40GBASE-LR4, 40G QSFP+ DAC/AOC):** QSFP28 ports are backward compatible with QSFP+ transceivers and DAC cables at 40G — connecting to existing 40G infrastructure at a tower site without media converters or adapters.

- **4×25G (QSFP28-to-4×SFP28 breakout DAC or AOC):** Each QSFP28 port's four internal 25G lanes exposed as four independent 25G SFP28 connections — the maximum breakout configuration. All four QSFP28 ports used as 4×25G breakouts = 16× independent 25G connections from a single outdoor switch. For a tower site where 16 downstream 25G sector APs, CPE aggregation nodes, or outdoor switches need individual 25G connections, this is the configuration that makes the CRS504-4XQ-OUT a 16-port 25G outdoor aggregation switch at USD 899.00.

- **4×10G (QSFP28-to-4×SFP+ breakout DAC or AOC):** Four 10G SFP+ connections from each QSFP28 breakout port — up to 16× 10G connections from all four ports. For a tower site with 16 downstream 10G devices, the four QSFP28-to-4×SFP+ breakout cables provide 16 independent 10G connections without a separate 10G switch.

- **1G:** Standard Gigabit operation in the QSFP28 ports — backward compatibility extending to legacy Gigabit infrastructure.

- **Mixed configuration example (MikroTik's own):** "100 Gigabits on one port, 40 Gigabits on the other, 4×25 Gigabits on the third, and maybe some 10G or 1G cables on the fourth." All four ports can simultaneously operate at different rates and breakout configurations — the 98DX4310 handles the mixed-rate forwarding in hardware.

This per-port rate and breakout flexibility is the operational characteristic that makes the CRS504-4XQ-OUT a genuinely versatile outdoor aggregation platform rather than a single-purpose 100G switch. An outdoor tower installation with a mix of legacy 10G backhaul equipment, current 25G sector APs, and a 100G fiber uplink to the ISP core can connect all of them to a single CRS504-4XQ-OUT without any external media converters or rate adaptation equipment.

**Passive cooling in an IP66 enclosure — the critical design achievement**

The CRS504-4XQ-OUT is passively cooled — no fans — inside a sealed IP66 enclosure. This combination is a genuine engineering achievement: the IP66 seal means no airflow path through the enclosure, yet the 98DX4310 switch ASIC and QCA9531 management CPU must dissipate their thermal load within the sealed housing across a -40°C to +70°C ambient operating range. The solution is the enclosure itself acting as a distributed heatsink — the CRS504-4XQ-OUT's aluminium or steel outer shell conducts heat from the internal components to the enclosure surface, where it dissipates to the ambient environment by convection and radiation.

The operational consequences:

- **No fan failure risk:** Fans are the most common point of mechanical failure in outdoor network equipment. In an IP66 sealed enclosure at a tower site or rooftop location where maintenance access is difficult, scheduled, or costly, fan failure is the failure mode that causes unplanned maintenance visits. The CRS504-4XQ-OUT's passive cooling architecture eliminates this failure mode entirely.

- **No fan noise:** Relevant for outdoor event venues and locations where acoustic impact is a consideration.

- **No fan maintenance:** No filter cleaning, no fan bearing lubrication, no scheduled replacement — the CRS504-4XQ-OUT requires zero cooling-related maintenance across its operational life.

- **Sealed against insects and moisture:** Fan-cooled enclosures require ventilation openings that also admit insects, dust, and humidity. The IP66 sealed enclosure has no ventilation openings — no insects, no dust, no moisture ingress regardless of installation environment.

The 25W max power consumption without attachments — and 44W max total — is the thermal envelope that the passive cooling architecture must manage. At 44W total dissipation in a sealed IP66 enclosure, the external surface temperature under worst-case load at +70°C ambient will be elevated — confirm from the product brochure whether any surface temperature advisory applies for installer contact protection at high-load, high-ambient operation.

**3 power inputs — outdoor deployment flexibility without a rack PDU**

The CRS504-4XQ-OUT's three power input paths are specifically configured for outdoor deployment scenarios where AC mains power is not available at the installation point:

- **DC jack (36–57V):** The primary power input for a tower or rooftop installation where a DC power feed is run from the equipment room to the outdoor switch location. The 36–57V range covers 48V DC power plants (standard in telecom tower infrastructure) and 24V or 36V industrial DC feeds.

- **2-pin terminal (36–57V):** A direct DC terminal block for hard-wired installation — the preferred power connection for a permanent outdoor installation where a weatherproof DC cable termination is required rather than a removable barrel connector. For a tower installation where the DC cable is routed through conduit to the switch mounting point, the 2-pin terminal provides a mechanically secure, weatherproof connection.

- **802.3bt PoE-in (43–57V) on the management Ethernet port:** 802.3bt (PoE++) power input at 43–57V — powering the entire switch from the management Ethernet cable run from an 802.3bt-capable PoE switch in the equipment room below. The included Gigabit PoE injector provides the PoE injection capability for deployments without a native 802.3bt PoE switch. For a rooftop or pole-top installation where running a separate DC power cable alongside the management Ethernet cable is impractical, 802.3bt PoE-in on the management port provides both power and management connectivity from a single cable.

The included 48V 0.95A power adapter provides out-of-box AC-to-DC powering via the DC jack — the standard configuration for bench testing or installations near an AC outlet. The included Gigabit PoE injector enables the 802.3bt PoE-in path from a non-PoE Ethernet source.

**MLAG — outdoor switch-level redundancy for tower and venue deployments**

MLAG (Multi-chassis Link Aggregation) is supported on the CRS504-4XQ-OUT via the 98DX4310 ASIC — the same hardware-assisted MLAG capability documented for the CRS510-8XS-2XQ-IN. Two CRS504-4XQ-OUT units deployed at adjacent tower sites or at two physical locations at the same venue can form an MLAG pair — downstream devices with dual uplinks spanning both switches see a single logical aggregated link. If either CRS504-4XQ-OUT loses power or connectivity, the MLAG bond continues operating on the surviving unit without reconfiguration on the downstream devices.

For a tower deployment where two CRS504-4XQ-OUT units are installed at the top of adjacent towers in a ring or mesh topology, MLAG provides path redundancy between the towers — a link failure between towers does not cause a traffic blackhole if the MLAG bond spans both tower sites. MikroTik explicitly lists MLAG as a supported feature.

**The outdoor event venue deployment context**

MikroTik's own product description specifically highlights outdoor event planning as a deployment scenario: "when it comes to outdoor event planning, you can never be too prepared — so having multiple powering options is a must." This is an explicit product positioning statement for temporary and semi-permanent outdoor high-bandwidth deployments:

- **Stadium and arena outdoor connectivity:** Temporary 100G backhaul switching for outdoor broadcast, media, or public Wi-Fi infrastructure at a stadium perimeter, parking lot, or outdoor event space — powered from a generator-fed DC distribution panel via the 2-pin terminal.

- **Outdoor broadcast and production:** A film or broadcast production deployment where multiple 100G-capable cameras, encoders, or storage nodes need 100G switching at an outdoor production site — the CRS504-4XQ-OUT deployed on a mobile production truck or temporary equipment shelter.

- **Festival and concert venue Wi-Fi infrastructure:** Large outdoor music festivals or sporting events deploying 100G fiber backhaul between stage, FOH, and back-of-house locations — the CRS504-4XQ-OUT at each location aggregating the 25G or 100G fiber runs.

- **Emergency and disaster response:** Temporary network infrastructure deployed at outdoor incident command posts, emergency operations centres, or mobile command vehicles — where 100G switching capability is needed outdoors without permanent installation.

**CRS504-4XQ-OUT versus CRS510-8XS-2XQ-IN — choosing the correct 100G switch**

Both share the same 98DX4310 Prestera ASIC and QCA9531 management CPU. The differences drive the deployment decision:

- **CRS504-4XQ-OUT (USD 899):** 4× QSFP28 only, no SFP28 ports, IP66 outdoor, passive cooling, 3× DC power inputs, pole/wall mount. Correct for: outdoor tower sites, rooftop aggregation, outdoor venues, any deployment requiring IP66 and passive cooling. Up to 16× 25G via QSFP28 breakout.

- **CRS510-8XS-2XQ-IN (USD 999):** 8× SFP28 + 2× QSFP28, indoor 1U rack, active cooling (2 fans), 5× power inputs including dual hot-swap AC PSU, rack-mount ears. Correct for: server room, data centre, indoor rack deployments requiring direct 25G SFP28 server connections and hot-swap PSU redundancy.

For a deployment that crosses the indoor/outdoor boundary — a tower site where the 100G switching lives outdoors at the tower head and the servers live indoors in the equipment room — the correct architecture is CRS504-4XQ-OUT outdoors for tower aggregation, connected via 100G fiber to a CRS510-8XS-2XQ-IN or CRS518-16XS-2XQ-IN indoors for server rack connectivity.

**Canadian market note:** Certifications are CE, EAC, and RoHS — no FCC or IC (ISED) published. The CRS504-4XQ-OUT is a wired switch with no wireless transmitter. No ISED wireless device certification advisory applies. Confirm any applicable Canadian electrical safety certification (CSA, cUL) requirements with your distributor before listing. The absence of FCC/IC is not a compliance concern for a wired switch in Canada.

**5-year software support guarantee:** RouterOS v7 and SwitchOS updates free for life of product or minimum 5 years from date of purchase.

Key specifications:

- **Product code:** CRS504-4XQ-OUT

- **Architecture:** MIPSBE

- **CPU:** QCA9531, single-core, 650 MHz

- **Switch ASIC:** Marvell 98DX4310 (Prestera DX)

- **RAM:** 128 MB

- **Storage:** 32 MB FLASH

- **OS:** RouterOS v7 License 5 / SwitchOS (dual-boot)

- **100G QSFP28 ports:** 4× (backward compatible: 100G / 40G / 4×25G breakout / 4×10G breakout / 1G)

- **Max 25G breakout connections:** 16× (all 4 QSFP28 ports as 4×25G)

- **Management Ethernet:** 1× 10/100 Mbps (with 802.3bt PoE-in 43–57V)

- **Serial console:** RJ45

- **DC jack input:** 36–57V

- **2-pin terminal input:** 36–57V

- **PoE-in:** 802.3bt, 43–57V (management Ethernet port)

- **Total DC inputs:** 3 (DC jack + PoE-in + 2-pin terminal)

- **Max power consumption:** 44W

- **Max power without attachments:** 25W

- **Cooling:** Passive

- **IP rating:** IP66

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

- **MTBF:** ~200,000 hours at 25°C

- **Monitors:** PCB temperature, voltage

- **Key features:** VLAN, ACL, MLAG, jumbo frames, L3 hardware offloading, STP/RSTP, LACP, SNMP

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

- **Included:** 48V 0.95A power adapter, Gigabit PoE injector, hose clamp ×2, K-41 fastening set, K-72 fastening set

- **Suggested price:** USD 899.00