May 1, 201115 yr Just wondering what some others are seeing. In pretty much all the switches I deal with and servers, the GB selection only supports Full Duplex. As per the Wiki site, 1GB links are almost always full duplex. In rare occasions can you use half duplex. On most of the higher end mobo's I have they also only support GB at full duplex. Recently though I have been seeing a bunch of users on the forum reporting that their cards are supporting 1GB half/full (via ethtool). My most recent motherboard purchase, a Biostar AM3 with a Realtek NIC, when running ethtool, also reported this. I was having slow writes and weird freezes. Disbaled this, put in a quality HP NIC, ethtool reports 1GB full duplex support only, writes are fast and no more freezes. Wonder what other users are seeing via the ethtool command and what is with this Half duplex option for GB... Shawn
May 1, 201115 yr Edit: Wonder if this is related to your issues with the 8111E http://lime-technology.com/forum/index.php?topic=12559.msg119249#msg119249 Motherboard: M4A785-M NIC: Realtek 8112L Wired--->D-Link DGS-2205 Connected Duplex Mode: Full No issues with writes or reads that I'm aware of... NIC info (from ethtool) Settings for eth0: Supported ports: [ TP MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Half 1000baseT/Full Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Half 1000baseT/Full Advertised auto-negotiation: Yes Speed: 1000Mb/s Duplex: Full Port: MII PHYAD: 0 Transceiver: internal Auto-negotiation: on Supports Wake-on: pumbg Wake-on: g Current message level: 0x00000033 (51) Link detected: yes NIC driver info (from ethtool -i) driver: r8169 version: 2.3LK-NAPI firmware-version: bus-info: 0000:03:00.0
May 1, 201115 yr mine is a dreaded atheros nic NO ISSUES at all on my setup .. Settings for eth0: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Advertised pause frame use: No Advertised auto-negotiation: Yes Speed: 1000Mb/s Duplex: Full Port: Twisted Pair PHYAD: 0 Transceiver: internal Auto-negotiation: on MDI-X: Unknown Supports Wake-on: g Wake-on: d Current message level: 0x0000003f (63) Link detected: yes
May 1, 201115 yr Author mine is a dreaded atheros nic NO ISSUES at all on my setup .. Settings for eth0: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full And yours, properly, only shows support for GB at full duplex. Shawn
May 2, 201115 yr Gig-E does support half duplex. Support for only full duplex is a cost saving measure by thrifty Ethernet vendors (A trend started by Cisco I believe. A whore of a company that cares little for standards.) Technically, the proper result is to have support for both half and full duplex. You paid for Gigabit Ethernet but your gear does not support half-duplex operation. You got ripped-off. But, it would not be funny if you were in a place that only had gigabit Ethernet hubs available.
May 4, 201115 yr Author Have you ever seen one of these mythical hubs? I haven't... and you are correct, Cisco really forced GB full Dup by simple not adding in an option to support half on their switchs. But it also kept costs down. Broadcom and Intel did the same on a lot of their nic's as well. Procurve quickly followed suit and the rest is history.... This is why I am asking... especially recently with the issues a bunch of us seeing with the Realtek chipset. I think now they may be messing around with the protcol, lord know MS does it all the time. Which is why we are seeing NIC's "support" half duplex GB link when there is no real need, and pretty much no switch out there that supports it. I put the higher end NIC in my server, only supports full dup and low and behold everything is golden. I am not trying to get into the debate of the specifications, yes, there is support for half duplex... but it is pretty much non existent. So why all these NIC's showing up that at least seem to indicate they support it? And onboard nic's at that... Just seems weird... Especially after the fustration of a bunch of days of troubleshooting server freezes.... My two cents. Shawn
May 4, 201115 yr These hubs are not mythical just old. They still have government, non-profit, and foreign users. Cost savings I can understand but if systems claim to support both half and full duplex and don't operate as claimed then avoid those manufacturers. I agree with you in spirit; although, I have an appreciation for legacy systems. An engineering maxim: Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away. Antoine de Saint-Exupery
May 4, 201115 yr Author An engineering maxim: Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away. Antoine de Saint-Exupery To true! Shawn
May 12, 201115 yr Author Interesting note - the Realtek 8111E drive on my mobo that was having the problems, showing Half Duplex support for full GB, check on a Windows 7 system that uses exact same setup (both boards/cpu/ram where purchased at same time). Windows 7 only show support for GB at full duplex - no half duplex option. So, I wonder if it isn't so much the chipset itself, but, the driver included in this version? Might 5b6a have a better drivers? Shawn
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