No experience on my side with PHY config, unfortunately. Fortunately, I've had success with just plugging optics modules into the ports. They seem to just work. I've used multimode (-SR) and single mode (-LR) without issue (though I can't recall the exact make/model at this time; sorry that's not too helpful!). I'd suggest asking for a sample/loaner from your manufacturer of choice to try it first.
Are you plugging into a switch or directly to a NIC? I've got no experience directly into a NIC, but can offer the following if you've got a switch partner: The 3m copper cables do typically have some bit errors in the direction switch -> ROACH, mostly, I suspect, because we haven't tuned the PHY's RX pipeline from defaults. But if you use good cables, it's not too bad. Out of 128 links currently in use, we have 3 that show single bit BER as poor as ~3.7e-6. I consider that pretty bad. It might actually be due to bad SFP+ mezzanine cards because they're from a very early prototype batch. The other links are all better than 1e-12. Mellanox have a patch for their switches which boosts their TX and this then works really well when using their 3m copper cables. Broadcom devices (almost all other common 10G switches out there) seem to work fine out-the-box with 3m copper cables. Over the last two months, I've used Huawei CE6850; Arista 7050S and 7150S; Extreme Summit X770; HP 5930; A-L Omniswitch 6900; Dell Z9500, Z9000 and S4810s; Mellanox SX1036 and SX1012 so far. They all work fine. The Mellanox cables are cheap, and are pretty good. I've also used 3m cables from Arista and Huawei, and 5m breakout units from HP, and 5m SFP-SFP from Arista. These also worked ok. For some reason, the Extreme 2m breakout cables showed some more errors than other parts, and consistently had problems interfacing to HP 5930s, though I'm not yet sure why because they look like nice beefy, well-made, cables. We've also tried some 3m "no-name" brands from Digikey, which worked too. If you really want lossless short-range transmission without having to think about any of this stuff, I recommend trying to find some AOC cables. We've had good success with these on ROACH-1's CX4 ports. Jason Manley CBF Manager SKA-SA Cell: +27 82 662 7726 Work: +27 21 506 7300 On 12 Sep 2014, at 5:20, shu.lean <[email protected]> wrote: > Hi all, > > Do anyone have experience on configuration of 10Gbe PHY chip? for > example,SFP+ mezzanine card that plugs into roach2 is used in two different > system. > One's transmission distance is more than 300m and the cable is made of fiber. > Another's transmission distance is only 3m and the cable is made of copper. > How to configure the 10Gbe PHY chips in these two system? Shall PMA/PMD be > configured to different types? Or default configuration works in both of the > two systems? > > And since there is only one pair of differential line between the pin of PHY > chip and SFP+ module and the data rate is as high as 10Gbps, what about the > requirement of PCB materials? > > Thanks! > > Lin > >
