I have a router that has a 10G Wan Fibre but on the lan side there’s only 1x 10G RJ45 port. So I bought a MikroTik CRS305-1G-4S+IN switch becuase on my home network, I have another two CRS310 switches. I thought I can just get a 10G RJ45 transceiver and connect the CRS305 with the router. Well, it works but it also overheats. I tried attaching heatsinks and fans but it still overheats. So I’m looking now for something else.
I saw the CRS309-1G8S±INL. To me it seems that it has much better (still passive) cooling than the CRS305. However I’m not sure if that cooling is sufficent because the 10G RJ45 transceivers produce a lot of heat. Will I also have overheating problems with the CRS309? If so, what else can you recommend, so I can you the 10G RJ45 LAN port on my router/modem?
10Gbps RJ45 modules from any vendor dissipate quite a lot of heat and are thus problematic when used in passively cooled appliances. Mikrotik published a general guidance for S+RJ10 modules with some suggestions. But these suggestions only improve the problem so far.
So: either use actively cooled switches or start using DACs or optical SFPs for speeds higher than 2.5Gbps.
I’d say that any of passively-cooled solutions will somehow bear with single 10Gbps RJ45 module. But not with more of them. If you have to use UTP cables to connect your gear to 10Gbps switches, then your only option is to go with actively cooled device, such as [rl=https://mikrotik.com/product/crs312_4c_8xg_rm]CRS312-4C+8XG-RM[/url] or any of actively-cooled XS models.
If you have to use UTP cables to connect your gear to 10Gbps switches, then your only option is to go with actively cooled device, such as > CRS312-4C+8XG-RM > or any of actively-cooled XS models.
Thanks for the recommendation - the price is in a different league. You mention UTP cable. Does it matter whether it’s shielded or not? I’m using currently a shielded cat 7 network cable.
The CRS309 has 8x SFP+ ports and on the back heatsinks. If I juse use S+RJ10 module in slot 1 and use the 7 and 8 for the 10G fiber transceivers, could that be run (as suggested in S+RJ10?
No, it doesn’t matter (much). The problem with 10Gbps over UTP cables is that Tx amplifiers for 10Gbps are very energy ineffective, UTP cable category doesn’t change this much. And the inefficiency means that excess ebergy is converted into heat, but SFP modules aren’t designed to dissipate lots of heat (no heat dissipation surfaces, only contact with SFP port case which then has to be cooled this way or another).
Optical modules are much nicer in this regard, so your idea about use of CRS309 (one RJ-45 module, the rest optical modules) would probably work.
If only the router had a SPF+ slot for the LAN side or the MikroTik switches a 10G RJ45 slot then there would be no problems. I could have 25Gbps internet here for the same price as I have the 10G one. Only difference is the setup fee. Monthly rate is the same. But having already trouble getting 10G to work (properly), I’d even have more troubles for 25G.
NO, not longer, length matters. Total capacitance and resistance rise with length.
UTP shielding has no effect on energy efficiency is the prior point.
High capacitance degrades frequency bandwidth.
High resistance makes energy efficiency worse.
Good things:
UTP higher category (more twists per meter) improves noise immunity.
UTP shielding improves noise immunity, valuable for very long lengths, pointless at short lengths.
At very short lengths the highest category levels are money poorly spent.
Since Category 5e & 6 are mainstream, choose a shorter length of either.
In the light of common practices in networking, it seems to me that jumping from 1G/s to to 10Gb/s is a too long jump as it introduces thermal or compatibility issues we didn’t have to deal with in the past.
Maybe going from 1Gb/s to 2.5Gb/s would be a smarter move allowing bandwidth increase without 10Gb/s hassles.
I hope Mikrotik will soon update its product portfolio to include 2.5Gb/s where currently 1Gb/s or 10Gb/s exist.
Oh yes we did. I was there for the rise of Fast & Gigabit Ethernet. Thermal issues, not so much (mostly because SFPs didn’t exist yet), but compatibility issues? Up the wazoo.
My main switch at home is a CRS309, but I also use a CRS305 my startegy is to always try to avoid 10G RJ45 ports. First choice is a DAC cable (cheap, low power, but short runs only), second choice is using MM SFPs with fibre. (bit more expensive, but not much, less power than RJ 45 SFP+) . I only use RJ45 if I must. In this case I use only every second slot and I put some small heat sinks on the SFP+ modules themselves (don´t forget the thermal pads between the SFP and heat sink).
Also non MT 10G RJ45 Modules from China tend to stay cooler than MT modules (if they work).
For the copper cable: theoretically at least Cat6 is needed, but I have some 10G Links over Cat5e, which do work well.
Shielding for the cables is only needed for two reasons: if you have lots of cables tightly packed, you will have issues if those cables are not shielded.
If you have long runs it is better to have shielded cables for better lightning protection. (shielded cables help to lessen the potential difference between the two ends of the cable if a lightning strikes).
Very short, very sweet!!