From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Carlson Date: Fri, 23 Apr 2010 03:46:28 +0000 Subject: Re: CRC-16 or CRC-32 Message-Id: <4BD11814.6090102@workingcode.com> List-Id: References: <291B2C7721AC7B49AD11449A2883992E2C4A9BDC3C@SINTEFEXMBX01.sintef.no> In-Reply-To: <291B2C7721AC7B49AD11449A2883992E2C4A9BDC3C@SINTEFEXMBX01.sintef.no> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ppp@vger.kernel.org On 4/21/2010 5:17 AM, Milan P. Stanic wrote: > On Wed, 2010-04-21 at 10:10, Jan Just Keijser wrote: >> the second problem is: if you want to add CRC32 support then you'd >> have to get it into the linux kernel . that will take *quite* some >> time (unless you can live with patched linux kernels). > > It wouldn't be so hard to push it to the kernel because Paul Mackerras > is/was on this list and he is the ppp driver maintainer, I hope ;) It's a little tricky to implement the feature *well*. You have to be able to withstand your peer restarting -- which means that while you're in CRC-32 mode, you have to be able to accept and process an LCP Configure-Request frame with a CRC-16 FCS on it -- and you need to be tolerant of peers that are unable to handle switching -- which means sending LCP Configure-Request messages with more than one FCS. -- James Carlson 42.703N 71.076W