Dedicated 2.5GBASE-T SFP+ transceivers that run cooler than 10GBASE-T transceivers?

[Michael Stora]

My main switch (MikroTik CRS309-1G-8S+IN) is running very hot with 3 10GBASE-T SFP+ transceivers (even spaced in non-agacent ports). I did the popular fan mod but it was loud and only kept the closest port cool.

I have a 10GBASE-T NAS, a 2.5GBASE-T WiFi Router (Multiple VLANS--untagged so it needs it's own port), and a 2.5GBASE-T employer computer (only device on a "work" VLAN) all connected to SFP+ to 10GBASE-T transceivers which run very hot even when functioning at 2.5G. The NAS is a neccessary evil but can I get dedicated SFP+ to 2.5GBASE-T transceivers which put out significantly less heat that 10GBASE-T being used as 2.5GBASE-T?

For everything else 2.5GBASE-T I am using unmanaged switches on their own VLAN with 1 or 2 SPF+ ports to do the conversion and those are all connected with DAC in the same room and MMF in other rooms as in a managed switch on the far end of the house. Unfortunatley in a few cases I need RJ45 transceivers.

 

[blunden]

I haven't looked into 2.5GBase-T transceivers, but there are at least 10GBase-T transceivers that draw less power than the common "cheap" ones that are limited to a 30 meter range. The ones I'm thinking of are the 80 and 100 meter range transceivers.

Ubiquiti seems to have the cheapest 100 meter one:

SFP+ to RJ45 Adapter - Ubiquiti Store

SFP+ to RJ45 transceiver module that supports 10G connections up to 100 m.

store.ui.com

They are also available from FS.com for roughly double the price last time I checked. The 80 meter ones seem a bit more common amongst the other brands like 10Gtek, etc.

 

[NPS]

Could be cheaper and equal in power consumption to buy a small 2.5GBaseT switch with SFP+ uplink and connect that to your CRS309-1G-8S+IN using a DAC.

 

[blunden]

Could be cheaper and equal in power consumption to buy a small 2.5GBaseT switch with SFP+ uplink and connect that to your CRS309-1G-8S+IN using a DAC.

Yes, that could certainly be the case.

Those cheap unmanaged 4*2.5GBase-T + 2*SFP+ switches cost about the same as a regular 10GBase-T transceiver, sometimes less (at least on AliExpress). They are also very power efficient according to the measurements from STH. I actually bought one of those as basically a signal repeater that I might end up needing later this year.

 

[Michael Stora]

I'm going to be giving the $21.99 Sodola 2.5G transceiver on Amazon (plus a 10% Coupon) a try. I bought one last year and returned it because it would only negotiate SFP/1000Base-T speed. I just noticed deeper down in the description that there is a dip switch in the nose to enable 2.5G which I did not notice last year--Like most of this stuff it was shipped with absolutely no instructions.

If that fails, I will use a cheap unmanaged switch as a 2.5GBase-T adapter as suggested.

 

[nexox]

I will be interesting to see if it can negotiate a 2.5G connection on the switch side, I was under the impression that only the Mikrotik branded 10GBaseT modules could do that.

 

[Michael Stora]

I will be interesting to see if it can negotiate a 2.5G connection on the switch side, I was under the impression that only the Mikrotik branded 10GBaseT modules could do that.

I never got a chance to figure out as the module was not compatible. I used an SFP+/2.5GBase-T switch instead.

 

[WhiteNoise]

Sorry to necro this thread, I wonder if somebody found cheap and low temp 2.5GbaseT/SFP+ transceivers.

 

[kyled]

I've been using this 10Gtek one with a Mikrotik CCR2116-12G-4S+ and a Google Fiber GPON ONT.

You have to disable auto negotiation but it does link at 2.5GbaseT once you do that. It also needs to be connected to a device with a SFP port that supports HSGMII, most of what you'll find people talking about this is for GPON SFP ONTs but the 2.5GbaseT SFP seems to work the same way.

 

[WhiteNoise]

I thought these Nbase set, including 2.5GbaseT all used SFP+ with XGMII and inserted ad hoc empty frames to fill the gap to 10G.

Anyway, Does it run cool?

Do you know which PHY used? I suspect most are based on RTL8221B.

 

[kyled]

It runs much cooler than any of the 10GbaseT SFPs I have. 10Gtek's site says its RTL8221

 

[WhiteNoise]

Do you have 10GbaseT 80m or 100m variants? Those should be the cool ones. The 30m are hot.

Anyway, thanks for the info. If I 2.5g module for cheap, I'll give it a shot