From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Updegraff Date: Thu, 23 Aug 2007 09:47:47 -0500 Subject: [U-Boot-Users] Multicast TFTP problems In-Reply-To: <46CD94A5.8070606@qstreams.com> References: <46CD5641.7060306@semihalf.com> <46CD94A5.8070606@qstreams.com> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Sorry all; I've lost access to my testbed hardware, so for now am out of the loop. > Rafal Jaworowski wrote: >> Dave, >> >> I'm having problems with tftp transfer with current U-Boot running on >> MPC5121 (FEC controller); since your mcast tftp implementation we first >> attempt to transfer using some bigger blocksize: >> #define TFTP_MTU_BLOCKSIZE 1468, and it seems my problems are related to >> this size. >> >> When running current code (ET_DEBUG enabled) it fails like the following: >> >> => run load >> Using FEC ETHERNET device >> TFTP from server 192.168.1.1; our IP address is 192.168.160.77 >> Filename '/tftpboot/ads5121/u-boot.bin'. >> Load address: 0x100000 >> Loading: send option "timeout 5" >> Got OACK: timeout 5 >> Blocksize ack: 1468, 1468 >> T T T T T T T T T T >> Retry count exceeded; starting again >> Using FEC ETHERNET device >> TFTP from server 192.168.1.1; our IP address is 192.168.160.77 >> Filename '/tftpboot/ads5121/u-boot.bin'. >> Load address: 0x100000 >> Loading: send option "timeout 5" >> Got OACK: timeout 5 >> Blocksize ack: 1468, 1468 >> >> Abort >> => >> >> It fails with TFTP_MTU_BLOCKSIZE values above 1454, but it's ok with >> anything up to this (including 1454): >> >> => run load >> Using FEC ETHERNET device >> TFTP from server 192.168.1.1; our IP address is 192.168.160.77 >> Filename '/tftpboot/ads5121/u-boot.bin'. >> Load address: 0x100000 >> Loading: send option "timeout 5" >> Got OACK: timeout 5 >> Blocksize ack: 1454, 1454 >> ########### >> done >> Bytes transferred = 157720 (26818 hex) >> => >> >> Any hints on these observations? What might be going wrong here? >> >> kind regards, >> Rafal >> > TFTP packets are structured as follows: > > | Eth header (14 bytes) | IP header (20 bytes) | UDP header (8 bytes) | > TFTP message | Eth FCS (4 bytes) | > > You can see that the total overhead is 46 bytes. If your network port's > maximum MTU size is 1500 bytes (the default), the math works out for a > maximum TFTP PDU size of 1454 bytes. > > However... the Ethernet header/trailer is not supposed to be included in > the MTU. I suspect we have a terminology problem here. Let me dig a bit > further to find out what's going on. > > regards, > Ben > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/