| 1 Jun 2025 |
 K900 | B u t | 12:03:39 |
 emily | switches that only take 10G and nothing else are definitely a thing | 12:03:40 |
| K900 | SGMII ends at 1G | 12:03:45 |
| emily | right | 12:03:51 |
| K900 | And USXGMII starts at 5G | 12:03:53 |
| K900 | In reply to @emilazy:matrix.org
switches that only take 10G and nothing else are definitely a thing They very likely just take USXGMII | 12:04:10 |
| emily | right | 12:04:31 |
| K900 | And the reason people say they only take 10G is because 5G SFP modules are bigfoot | 12:04:33 |
| emily | so I guess, 2.5G was forced into SGMII? | 12:04:40 |
| emily | so if you are making such an SFP+, you can advertise SGMII with 2.5 and USXGMII with 5 and 10 | 12:04:52 |
| emily | and it'll work with both 2500BASE-X and 10000BASE-X only things? | 12:04:59 |
| emily | isn't that… autoneg? | 12:05:03 |
| K900 | No that's the fun part | 12:05:06 |
| K900 | It wasn't | 12:05:09 |
| K900 | Ever | 12:05:10 |
| emily | maybe I have no clue what autoneg is! | 12:05:10 |
| K900 | The only IEEE standard way of doing 2.5G specifically over SFP is 2500base-x | 12:05:30 |
| emily | uh. I thought SGMII was like an umbrella term for 1000BASE-X. | 12:05:50 |
| emily | and USXGMII is 10000BASE-X and 5000BASE-X. | 12:05:59 |
| emily | are they separate things entirely? | 12:06:04 |
| K900 | 2.5G SGMII isn't real | 12:06:07 |
| K900 | It's a weird vendor thing | 12:06:14 |
| emily | like when you say this. is this neither SGMII nor USXGMII? | 12:06:20 |
| K900 | That was never standardized | 12:06:24 |
| emily | I have no idea what SGMII and USXGMII actually mean. | 12:06:27 |
| K900 | In reply to @emilazy:matrix.org
like when you say this. is this neither SGMII nor USXGMII? Yes | 12:06:30 |
| emily | …explain | 12:06:37 |
| K900 | SGMII is the standard MAC to PHY interface | 12:06:46 |
| K900 | USXGMII is that but more and also faster | 12:06:55 |
| K900 | With the base-x modes the phy is host side | 12:07:22 |
