tag:blogger.com,1999:blog-37798047.post2585282875871978837..comments2024-01-16T05:48:33.523-05:00Comments on Errata Security: What's the max speed on Ethernet?David Maynorhttp://www.blogger.com/profile/09921229607193067441noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-37798047.post-51824360794141342382013-10-08T07:42:20.337-04:002013-10-08T07:42:20.337-04:00Thank you for the protocol rundown, but I would li...Thank you for the protocol rundown, but I would like to add two things to the discussion.<br /><br />First I agree with all of the above, but would like to point out you are assuming only standard frame size, and ignoring the ability to use jumbo frames, which can carry up to 9000 bytes of payload. As you may not be aware of, leverages the buffer size, Jumbo frames decrease processing time, reduces fragmentation and power required to move a data stream. I would suggest you check out the "Raising Internet MTU" located: http://staff.psc.edu/mathis/MTU/<br /><br /><br />Second, a more complete Protocol Overhead for ethernet, Gigabit Ethernet with Jumbo Frames, ATM, Packet Over SONET (POS), Generic Framing Procedure, Multi Protocol Label Switching (MPLS) can be located at Phil Dykstra's Page located: http://sd.wareonearth.com/~phil/net/overhead/<br /><br />Again thanks for the writeup.Joe Kleinhttps://www.blogger.com/profile/17132575668974268183noreply@blogger.comtag:blogger.com,1999:blog-37798047.post-68451138149163850212013-10-08T04:39:43.193-04:002013-10-08T04:39:43.193-04:00"But in practice, Linux only transmits about ..."But in practice, Linux only transmits about ~1.3-million-packets/second on a 1-gbps link. I don't know why this is."<br /><br />I'm not sure this is effectively the case, but that's about what we noticed to be the per core pps rate that the linux TCP/IP stack is able to get to, this will obviously change based on your cpu. So the next question is the driver, some drivers are able to use some kind of multiqueuing, most ixgbe does, but it is likely that this is not handled by most 1G drivers.<br /><br />You can have a look at the options of the buffers, rings, and queues for your driver.<br /><br />Also, there is a 'poll mode' supported in linux now, I've never used it myself, but it gets rid of the interrupt overhead and may be faster this way, again the support of this mode is probably dependant of the driver implementation.<br /><br />Hope this can be of some help.Anonymoushttps://www.blogger.com/profile/02302722132229042016noreply@blogger.comtag:blogger.com,1999:blog-37798047.post-61393253794591581802013-10-08T01:54:07.658-04:002013-10-08T01:54:07.658-04:00Ethernet does not directly code bytes into bits, i...Ethernet does not directly code bytes into bits, it uses a conversion to prevent long streams of 0's (otherwise clocks go out of sync).<br />Usually this comes down to 8 bits of data being represented by 10 bits on the wire.<br /><br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37798047.post-86053757087088831892013-10-08T00:40:46.942-04:002013-10-08T00:40:46.942-04:00The statement 'In normal Internet usage, packe...The statement 'In normal Internet usage, packets are 500-bytes in size . . .' is incorrect. <br /><br />There is no 'normal' Internet usage, and packet sizes vary widely.Roland Dobbinshttps://www.blogger.com/profile/06517186494484977438noreply@blogger.com