nanog mailing list archives
Re: Software router state of the art
From: "William Herrin" <herrin-nanog () dirtside com>
Date: Sat, 26 Jul 2008 15:46:50 -0400
On Sat, Jul 26, 2008 at 1:40 PM, Petri Helenius <petri () helenius fi> wrote:
William Herrin wrote:But cards like the Intel Pro/1000 have 64k of memory for buffering packets, both in and out. Few have very much more than 64k. 64k means 32k to tx and 32k to rx. Means you darn well better generate an interrupt when you get near 16k so that you don't fill the buffer before the 16k you generated the interrupt for has been cleared. Means you're generating an interrupt at least for every 10 or so 1500 byte packets.This is not true in the bus master dma mode how the cards are usually used. The mentioned memory is used only as temporary storage until the card can DMA the data into the buffers in main memory. Most Pro/1000 cards have buffering capability up to 4096 frames.
Pete, I'll confess to some ignorance here. We're at the edge of my skill set. The pro/1000 does not need to generate an interrupt in order to start a DMA transfer? Can you refer me to some documents which explain in detail how a card on the bus sets up a DMA transfer? Thanks, Bill -- William D. Herrin ................ herrin () dirtside com bill () herrin us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
Current thread:
- Re: https (was: Re: Exploit for DNS Cache Poisoning - RELEASED), (continued)
- Re: https (was: Re: Exploit for DNS Cache Poisoning - RELEASED) Jim Popovitch (Jul 24)
- Re: https (was: Re: Exploit for DNS Cache Poisoning - RELEASED) Matthew Petach (Jul 25)
- Re: https (was: Re: Exploit for DNS Cache Poisoning - RELEASED) Jim Popovitch (Jul 25)
- Re: https Patrick Giagnocavo (Jul 31)
- Re: https (was: Re: Exploit for DNS Cache Poisoning - RELEASED) Jasper Bryant-Greene (Jul 24)
- Re: https (was: Re: Exploit for DNS Cache Poisoning - RELEASED) William Pitcock (Jul 24)
- Re: https (was: Re: Exploit for DNS Cache Poisoning - RELEASED) Chris Adams (Jul 24)
- Re: https Ken A (Jul 24)
- Re: Exploit for DNS Cache Poisoning - RELEASED Tuc at T-B-O-H.NET (Jul 23)
- Re: Software router state of the art Petri Helenius (Jul 26)
- Re: Software router state of the art William Herrin (Jul 26)
- Re: Software router state of the art Florian Weimer (Jul 26)
- Re: Software router state of the art Petri Helenius (Jul 26)
- Re: Software router state of the art Florian Weimer (Jul 26)
- Re: Software router state of the art Chris Adams (Jul 26)
- Re: Software router state of the art Seth Mattinen (Jul 26)
- RE: Software router state of the art Darden, Patrick S. (Jul 28)