MikroTik CRS504-4XQ-IN Review Momentus 4x 100GbE and 25GbE Desktop Switch

4

MikroTik CRS504-4XQ-IN Software and Management

MikroTik offers management in three ways: WinBox, Webfig, or a CLI. Many networking power users will go directly to the CLI.

MikroTik CRS504 4XQ IN CLI Interface
MikroTik CRS504 4XQ IN CLI Interface

Still, in the sub $700 for a 100GbE switch price bracket, we sense that many users will want something easy to understand without learning a CLI. For that, there are two graphical management options. One is WinBox, MikroTik’s desktop application.

MikroTik CRS504 4XQ IN WinBox Interface
MikroTik CRS504 4XQ IN WinBox Interface

The other, WebFig, has a very similar set of functionality, but it runs in a browser rather than running as a desktop application.

MikroTik CRS504 4XQ IN Interfaces
MikroTik CRS504 4XQ IN Interfaces

Today’s 100GbE switches typically feature CLI-only management. Especially those that come via off-lease eBay specials. Having a management interface that is accessible with a GUI to a broader audience is important in a switch like this.

Aside from the management itself, MikroTik is using a higher-end switch chip than is found on many of its CRS300 series of switches, so we get more features.

MikroTik CRS504 4XQ IN Switch Chip Features
MikroTik CRS504 4XQ IN Switch Chip Features

One feature we get is the ability to do L3 hardware offloading. That gives a significant boost in performance when it is enabled. Here is the guide on that L3 HW offload feature.

MikroTik CRS504 4XQ IN Switch Chip L3 HW Offload Features
MikroTik CRS504 4XQ IN Switch Chip L3 HW Offload Features

All told, MikroTik is adding incrementally more features, but the L3 HW Offload one is perhaps one of the biggest it has added in some time.

MikroTik CRS504-4XQ-IN Performance

In terms of performance, we were able to get over 90Gbps on average through each port using our new FPGA-based traffic generator. We are leaving performance on the table here since that is a new setup we are still tuning. Still, that is not a bad result.

MikroTik CRS504 4XQ IN Cumulative Throughput FPGA Clients
MikroTik CRS504 4XQ IN Cumulative Throughput FPGA Clients

MikroTik has fancier test gear than we do, and here are MikroTik’s numbers:

MikroTik CRS504 4XQ IN MikroTik Performance Figures
MikroTik CRS504 4XQ IN MikroTik Performance Figures

Realistically, these are not the same as we get from higher-end switches, but they are also not bad with one exception: the routing figures. MikroTik uses the single-core 650MHz CPU to route traffic. Doing anything over the CPU yields very low performance. Our suggestion is to use only the Marvell Prestera hardware features.

Next, let us get to some of the challenges with a lower-cost switch like this.

The Biggest “Gotchas” of Cheap and Low Power 100GbE

Still, this is not a perfect switch. Sometimes to swap between 100GbE and 4x 10GbE SFP+ or 4x 25GbE SFP28, you end up tracking down cable/ NIC issues. We have had 1 in about 30 breakout cables we have used to an Intel E810 NIC we used for How to Install an Intel E810 100GbE Network Adapter in Windows 11. Often this is a FEC error. We have not seen the issue connecting to the MikroTik CRS518-16XS-2XQ-RM‘s 100GbE ports. On the one hand, 1 of 30 does not seem like a lot to us (~3%), but if you are that 1 of 30 individual, then you are going to be spending some time troubleshooting and may not love the switch.

The other big one is a huge missing feature. With 100GbE, 200GbE, 400GbE, and so forth networks, RDMA has become a mainstream feature and RoCE (V1/V2) have become extremely popular. This is largely due to the amount of data that has to move through the network stack. Bypassing that network stack via direct memory to NIC transactions saves an enormous amount of CPU cycles. We could not figure out how to get features like PFC working on this switch. We went to the MikroTik help docs and searched for RDMA, and we got absolutely nothing.

MikroTik Help Docs RDMA Search 2023 01 13
MikroTik Help Docs RDMA Search 2023 01 13

Larger 100GbE switch vendors have libraries dedicated to RoCE, iWARP, and more. Since that is something that many 100GbE users want to use, usually, there is documentation around it on a vendor’s site. We checked the MikroTik Wiki as well. It would be nice if there were simply an entry talking about RDMA networking.

MikroTik Wiki Search RDMA Search 2023 01 13
MikroTik Wiki Search RDMA Search 2023 01 13

We looked up the Marvell Prestera 98DX4310, and the spec table we found did not say that the switch chip supports it.

Marvell Prestera 98DX4310 Specs
Marvell Prestera 98DX4310 Specs

To us, that is the big feature miss. With 100GbE networking, RoCE(v2) is one of those features folks will want to use. There is still a lot you can do over a switch like this, but RoCE is probably not something we are going to see.

Taking a step back, this is a <45W and <$699 switch, so there are features that we just do not get. There may be some troubleshooting. We just upgraded our units to RouterOS 7.7, and we will see how that goes. New RouterOS versions can have noticeable bugs, but we have not run into those just yet.

Next, let us get to power consumption and noise.

4 COMMENTS

  1. IF my old data center pals decide to give me a couple used 2U/4Node Rome quads in say 2025, THEN this switch (with a couple 100/25Gbit quad breakout cables) would make for an excellent $HOMElab upgrade in my 12U rack.

  2. It’s a shame 100 GbE networking is so power hungry – with the exception of this switch obviously. I recently got hold of a Mellanox ConnectX-6 100 GbE NIC, and the Linux boot messages said the card was requiring 75 watts from the PCIe slot. Even with a quiet fan blowing directly on it, it got too hot to touch, so apparently a faster/noisier fan is needed.

    Hopefully newer generations using less power will hit the second hand market soon so we can have 100 GbE at home without turning it into a deafening sauna.

    As for MikroTik, my experience hasn’t been fantastic. I first bought a CRS309 (8x 10G switch) and it emitted a buzz and died when I powered it up and had to return it. The second item I bought was an RB5009 which wouldn’t power up, and it turned out they’d listed the wrong specs (since corrected) and said it supported PoE on ports it did not, so again I had to return it as it wasn’t possible to make it work in the scenario I had planned.

    The replacement CRS309 worked well enough, but it annoys me that if you change the wrong settings, it can suddenly pass all traffic via the CPU and then without warning your throughput suddenly drops to hardly anything (as mentioned in the article). It’s only after reading the fine print do you discover that while many options and modes are available, only a handful will actually work at wire speed.

    So while I used to think MicroTik made some pretty interesting hardware, I’m less keen these days given how much research you have to do over every little detail to make sure the product you’re buying can actually do things that go without saying in other products. I guess that’s just the cost of cheap hardware.

  3. The main issue with Mikrotik is reliability, they still sell a switch that has know issues (CRS354), they still sell a router that tends to reboot/crash for unknown reason (CCR2004) and they seem to find this normal, they just need to find a software workaround..
    You have threads on their forum spanning over two years about issues that never get fixed, essential features that get removed from ROS6 to ROS7 and take ages to be reimplemented.
    Now their boxes have very nice features for the price, ROS / Winbox is something the big brands should take inspiration from but the fact that you never know how stable their device will be in your use case is really a concern.

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