2.5 GE, more speed, more headaches

[Lord Evermore]

FWIW, I'm sure use-cases for jumbo frames exist, but I haven't yet seen them really come into play with my own foray into 2.5GBE.

I have a pretty low-end setup (cheap unmanaged switches, etc) and get around 2.1Gbps moving files around via SMB to and from my NAS (same model as yours), with an MTU of 1500. Could I eke out a little more speed by messing with the MTU? Maybe, but I'm not convinced of the benefit/cost. Perhaps the fact that I'm running SSDs in my NAS factors in too.

High MTU helps with CPU usage on the device, so if you had a cripple-slow processor, or you were switching for an ISP backbone, jumbo frames might be helpful. As far as I know, that's pretty much it. Getting 0.1% higher throughput, maybe, since we already can just about max out gigabit, on a home network probably isn't worth the hassle, and would make your router have to constantly break up frames when sending traffic to the Internet, while the incoming (majority) would be standard 1500/1472. Probably some devices still don't support jumbo frames simply because of the extra support and design effort, and the number of people who would call complaining that their network is down because they enabled jumbo frames without making sure the other end supported them, or when they didn't see a massive speed improvement.

you can't have additional VLAN interfaces that run on top of existing interfaces

All VLAN interfaces are run on top of existing interfaces...

But yeah unreliable 2.5Gb would suck if I had a reason to use it. Maybe it's still at the stage that you need to ensure the same brand at every point. Which is stupid since it's actually been around a while. But then Intel had such a bitch of a time making the i225/i226v chipsets actually work, they could be to blame for it not being popular, too.

 

[Lord Evermore]

I have some of that, and it works fine too. IMO 2.5G isn't any more problematic than 1G, the only downside is the strong likelihood that you don't really need it.

Man, if this had been available along with the high speed Internet services today, my roommate would have been saturating that link to a NAS almost continuously with porn. (He just downloaded it constantly and burned it to CDs which he collected in one of those huge folders. He didn't even watch most of it. And it was a particular genre.)

 

[Lord Evermore]

Actually optical drives are much too slow to keep up, with 1 x speed blu-ray at 100 Mbps IIRC. My drive is actually just USB 2.0 because that's fast enough.

CDs at 1X are 150 KILOBYTES per second! Blu-Ray 1X is 36Mbps. But what I meant was 2.5GbE going to a NAS, with multi-gig Internet, my old roommate would have been the archive for the Internet's porn (of a certain genre).

 

[Lord Evermore]

even the reused Cat5e cable that had been used for telephone lines 20+ years ago

2.5GbE and 5GbE are explicitly intended to be drop-in upgrades for homes and small businesses that won't require a cabling upgrade, both intended to work on Cat5e. (5Gb does need Cat6 for longer distances, but not Cat6a like 10Gb, and many places future-proofed a bit and already have Cat6 if they've had wiring installed in the last several years so for many users it is still a drop-in upgrade.)

 

[Lord Evermore]

it's "in spec" for 10GBaseT, and that's not something you generally want unless you have no other choice, eg I have one system that uses it because it has 10GBaseT onboard and all the PCIe slots are occupied with other things

I don't fully understand this statement. You DON'T want the ability to run 10GbE? I get it if you meant it's a chipset that doesn't support 2.5 or 5, just 1 and 10, and you don't have a 10GbE switch so you'd be stuck at 1Gb, but other than that? (And you're using that Cat6a patch cable so I assume you DO have a 10Gb switch.) And regardless of what your current hardware supports, why would you NOT be at least considering still having the copper be capable of 10Gb in the future?

 

[Lord Evermore]

If you hadn't trimmed their comment in your quote, you'd have the rest of the context to understand what they were saying.

I trimmed it because it seemed irrelevant. The first and second paragraphs were not explicitly linked in my mind. A literal reading of the sentence says you don't want Cat 6a cabling that is capable of 10GbE instead of Cat 6 unless you have no choice, which makes no sense. (Don't hold it against me that I read things as they're written and then ASK for clarification.) Just because fiber is a good way of doing 10Gb doesn't automatically mean Cat 6a is a bad choice. @iljitsch pointed that out in the post immediately afterward.

 

[Lord Evermore]

Remember when dropping your exposed computer equipment (with no moving parts) into a vat of mineral oil to dissipate heat was the thing? I'd love to open an IT room door and see a large aquarium full of un-cased switches and servers soaking in mineral oil, which of course is being pumped out to large radiators somewhere else. Preferably rigged with a cinematically-awesome robotic system for extracting each unit for maintenance/upgrades or plugging in cabling. And maybe a walkway above it with no safety railing for when the sysadmin needs to have a duel with a beancounter.

 

[Lord Evermore]

Can't believe manufacturers didn't jump on the chance to force such automatic identification into the spec (by hook or by crook) so that you can only buy cables that have an identifier chip built into them like Apple USB cables and people couldn't terminate their own cables anymore and had to hire someone certified to do it which authorizes them to purchase the connectors with the chip in them.