Steve, I very much appreciate your detailed reply and comments. They have enabled me to feel very confident in proposing FREESWITCH (using mod_spandsp & Sangoma E1 cards) to run a FAX OUT service for my Client. There is only one last question I have. My Client has requested that the initial installation runs on Windows Server 2008. Do you see any issues with the Windows version of FreeSWITCH using mod_spandsp (based on the service design I have already sent through)? I know the Sangoma A10x series of E1 cards do support Windows (via FreeTDM) so I do not see any issue there. Once again thanks so much for all your feedback. Kind Regards, Andrew Keil -----Original Message----- From: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] On Behalf Of Steve Underwood Sent: Monday, 9 May 2011 10:18 AM To: FreeSWITCH Users Help Subject: Re: [Freeswitch-users] Major deployment of outbound FAX on latest version of Freeswitch question On 05/09/2011 01:16 AM, Juan Antonio Ibañez Santorum wrote:
How much reliable FS + mod_spandsp is compared to other solutions (open source or not)? The open source options are:
Asterisk + spandsp Asterisk + Hylafax + iaxmodem + spandsp Freeswitch These are all tested and proven to give well below 1% failures, even with quite a lot of concurrent FAX channels in use, if things are set up well. They can give you bad failure rates if things are not set up well. I believe that right now you will have less trouble achieving a reliable setup with Freeswitch. Going forward, most of my effort goes into making the Freeswitch option the most thoroughly implemented one. The main commercial option is: Asterisk + Digium's commercial FAX Of course, there are numerous other fully commercial FAXing options which could be used in conjunction with things like Asterisk or Freeswitch The Digium FAX module is based on the well known Commetrex FAX engine, which is widely deployed, and should be capable of solid results. However, the module is more than just the core FAX engine, and some people do have serious trouble with the module. I have helped moved people off this, and onto Asterisk + spandsp, to improve their reliability. In a couple of those cases people were getting quite a lot of pages cut short when receiving FAXes with T.38, even though a wireshark log showed a perfect exchange, from which I could correctly decode these FAXes. The module was not reporting any errors. In a couple of cases strange machines were sending weird things the Digium FAX didn't cope with very well. I worked with these people to make sure spandsp did handle the weird stuff well, and we ended up with a more usable solution. These people told me that when they complained to Digium they got little help. The best was an offer of a refund. Paying to get some support didn't seem to work out too well for these people, but I guess if the support you are looking for is mostly in getting things configured and working on day one you might get value for money. All these solutions require reliable signaling and reliable media timing, and many people have setups which cannot achieve that. Most people don't understand how things work, and will claim a solution doesn't function for spurious reasons. For example, a number of people say the spandsp module for Asterisk doesn't work, because they keep getting a 488 response. That response has nothing to do with the FAX engine. It is a negotiation error that occurs outside the FAX engine. If they fixed their configuration the error would go away. However, many just move on, having "proven" to themselves the solution doesn't work.
2011/5/8 Steve Underwood <steveu@coppice.org <mailto:steveu@coppice.org>>
On 05/07/2011 04:02 AM, Andrew Keil wrote: > Steve, > > Thanks for your response. > > Further clarification on my part: > > 1) 20,000 to 30,000 pages per day to be sent out. So, this is fairly small scale. A single E1 will do fine. > 2) It will be an e-mail to fax style gateway (not fax to e-mail since that would involve inbound faxes) That covers a few requirements, depending what you expect to be in the e-mails - send the whole e-mail as a FAX; extract a PDF, Word document, etc. from an e-mail, and turn that into a FAX; and so on. > 3) The reason I asked about e-mail to PDF is the initial comments from my client requested the ability to send PDFs and WORD documents (I guess from attachments to the original e-mail), I understand the format that gets faxed should be TIFF so I saw on the freeswitch wiki email2pdf mentioned. Then ImageMagick can help get a PDF to TIFF. If the incoming e-mails are limited to ones containing PDFs and doc files to be extracted and turned into FAXes things you seem to have a fairly well defined requirement. OpenOffice can be used to turn the doc files into FAXable images, but I am not clear how well the newer docx files are handled. Ghostscript can be used to turn PDFs into TIFF files.
Avoid ImageMagick for this kind of work. It uses Ghostscript to do the hard work, but it doesn't get the best from it. If you use Ghostscript directly you get better control, and you can achieve good results. > Can I ask some more questions: > > Q1) Based on your experience what would be the average time (in seconds) to send a single fax page (TIFF file) via Freeswitch& Sangoma TDM? You can quote a TIFF file size to make it more accurate. From there I should be able to do the math to calculate my Client's requirements better. The time per page depends a lot on its complexity. I use a torture test file with images that take half an hour to send. Typical office work is probably 20s per page at 14400bps. > Q2) Running on CentOS and using mod_spandsp/Freeswitch& Sangoma TDM what percentage CPU usage would I expect to see if 30 concurrent faxes are being sent at the same time (ie. All channels of my E1 are faxing)? (The hardware would be a new 1U rack server from a major hardware vendor) The greater part of the CPU load is likely to be what you didn't list there - the processing from e-mail to FAXable TIFF files. A single E1 of FAXing is a really low load these days, though. > Q3) What version of CentOS 5.x would you recommend? Would the latest version 5.6 be fine? 5.6 is fine. > Q4) From memory there used to be different fax quality modes on fax machines (STANDARD, FINE& SUPER FINE or something like that). Is it possible to set the fax send quality from mod_spandsp (also can you provide an example)? If this is the case could you also answer question (Q1) based on the different fax send quality modes. You can't really set the quality in mod_spandsp. The quality follows the TIFF files to be sent. You can, however, select the image quality as you generate the TIFF files in Ghostscript. STANDARD, FINE and SUPERFINE are the right names, although many machines refuse to use SUPERFINE. > Q5) From exisiting deployments of Freeswitch using mod_spandsp (& Sagoma TDM cards (although this is not critical)) what is the largest number of concurrent outbound faxes done on a single box that you know of? I'm not sure of the biggest, but an E1 of FAXing is pretty small volume these days. The biggest number of channels should be in the hundreds. > I appreciate your feedback and experience. It sounds like this will work fine with the mod_spandsp/Freeswitch& Sangoma TDM combination on CentOS. > > I will most likely go for two servers with at least 2 x E1s in each, that way I future proof it a little and add redundancy. Plus my Client can start using Freeswitch for Voice related services also. On my side I can also test faxes going out on the first server and via a cross-over cable I can terminate them on the second server (for testing) - much nicer. > > Thanks again, > > Andrew Two servers with one E1 in each sounds like more than enough to meet your needs, unless your 30k pages per day occur over a fairly short working hours, and the customer demands rapid delivery. Then you might need more channels to deal with rush hour.
Steve
Steve _______________________________________________ FreeSWITCH-users mailing list FreeSWITCH-users@lists.freeswitch.org http://lists.freeswitch.org/mailman/listinfo/freeswitch-users UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users http://www.freeswitch.org __________ Information from ESET NOD32 Antivirus, version of virus signature database 6105 (20110508) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com