2.5Gbit to 1Gbit

[SomeWhereOverTheRainBow]

Has anyone here ran into an issue where a 2.5gbit nic did not properly negotiate to 1gbit connection for legacy switch causing the speed to range from 100~200 instead of 1000?

 

[L&LD]

Yes.

 

[SomeWhereOverTheRainBow]

Yes.

Obviously the quickest solution would be to upgrade the switch to a 2.5gbit, but is there another solution?

 

[L&LD]

Different cables/ends/termination.

 

[SwampKracker]

Upgrade your switch to support newer standards. Just keep your legacy 1Gb switch for the clients that don't like connecting directly to multi-gigabit devices.

 

[TheLostSwede]

Has anyone here ran into an issue where a 2.5gbit nic did not properly negotiate to 1gbit connection for legacy switch causing the speed to range from 100~200 instead of 1000?

There have been various hardware/software bugs from both Intel and Realtek, so yes, it's possible.
Neither company has been particularly forthcoming in the matter though. The Intel i225-series was the worst affected.

 

[Tech9]

Recent case - connection not negotiated at all:

New Asus RT AX88U Pro refuses to recognize cable plugged into WAN port

For almost the past decade I've been using an old ASUS RT-AC87R with no issues. One of the antenna broke on it so I decided I would upgrade to the Asus RT-AX88U Pro. When setting it up it immediately showed the WAN port light as red on the top of the router and in the control panel it says "The...

www.snbforums.com

 

[SomeWhereOverTheRainBow]

Upgrade your switch to support newer standards. Just keep your legacy 1Gb switch for the clients that don't like connecting directly to multi-gigabit devices.

Yea this is definitely the first path I thought about. I just wanted to make sure there wasn't a money saving alternative. I know the the 2.5gbit works fine when connected to other 2.5gbit. Thats how I discovered the issue. I troubleshooted down to the cabling to see if something gave, but nothing did so off I go to update my switch.

 

[tgl]

We've gotten spoiled by the fact that 1Gbps UTP ethernet is such well-settled technology: barring faulty patch cables or the like, most pairings of devices have Just Worked for a decade or two. The higher speed ratings seem not to be sorted out quite as well yet. I've not run into the exact issue described here, but I have had problems with a 10Gbps device that didn't get along with a 2.5Gbps switch. Also it seems way more likely for allegedly-higher-speed devices to not achieve their claimed speeds than it is at 1Gbps.

 

[SomeWhereOverTheRainBow]

We've gotten spoiled by the fact that 1Gbps UTP ethernet is such well-settled technology: barring faulty patch cables or the like, most pairings of devices have Just Worked for a decade or two. The higher speed ratings seem not to be sorted out quite as well yet. I've not run into the exact issue described here, but I have had problems with a 10Gbps device that didn't get along with a 2.5Gbps switch. Also it seems way more likely for allegedly-higher-speed devices to not achieve their claimed speeds than it is at 1Gbps.

I have a feeling that 1gbit switches are not interoperable with 2.5gbit nic sharing its connection. The issue being that it is an older technology that was not designed to negotiate the 2.5gbit of a single ethernet nic. In a world where it would work correctly we would expect devices sharing the 1gbit connection to be able to provide such 1gbit connection. But this is not the case. I am only achieving 100 to 200 mbits tops. This indicates that the nic is unable to provide a desired interoperability with a 1gbit switch. The only option is to upgrade the switch. The only thing I haven't tried is breaking out a managed switch and seeing if I can "force" the 1gbit link speed which may or may not resolve the issue. At either rate, I don't feel the need to connect a 24port managed switch to resolve something I only need four ports for.

 

[tgl]

I have a feeling that 1gbit switches are not interoperable with 2.5gbit nic sharing its connection. The issue being that it is an older technology that was not designed to negotiate the 2.5gbit of a single ethernet nic. In a world where it would work correctly we would expect devices sharing the 1gbit connection to be able to provide such 1gbit connection. But this is not the case. I am only achieving 100 to 200 mbits tops. This indicates that the nic is unable to provide a desired interoperability with a 1gbit switch. The only option is to upgrade the switch.

I would blame that 100% on the NIC, not the switch. It is not the older tech's fault if the newer tech fails to interoperate with decades-old specs. Having said that, if you're hoping to get to better-than-1Gbps performance, then yes you need to replace the switch.

 

[SomeWhereOverTheRainBow]

I would blame that 100% on the NIC, not the switch. It is not the older tech's fault if the newer tech fails to interoperate with decades-old specs. Having said that, if you're hoping to get to better-than-1Gbps performance, then yes you need to replace the switch.

Tbh I wouldn't be too concerned if the connection discrepancy wasn't several decades behind. I have tried 2 different reputable brand 1gbit unmanaged switches, so I am pretty sure the issue is with the nic as well that is why I haven't brought out the big guns managed switch. Thank you for helping bring clarity to the matter. This helps me present the argument to the significant other when I go to buy the replacements.