Hi, I know i doesn't make practical difference, but often it is the far end that is atually buggy, not out end.
A lot of the work in spandsp to increase success rate is to do with workarounds for issues in the remote machine, Steve On 3/13/09, Marshall Henderson <marshall...@gmail.com> wrote: > On Fri, Mar 13, 2009 at 11:07 AM, David Backeberg <dbackeb...@gmail.com> > wrote: >> >> On Fri, Mar 13, 2009 at 11:38 AM, Marshall Henderson >> <marshall...@gmail.com> wrote: >> > I recently read the thread entitled "Faxing Success Rate on PRI" which >> > dealt >> > with Asterisk/HylaFax/IAXmodem. I'm successfully using this 'recipe' in >> > a >> > few instances on systems with only a couple of analog lines all the way >> > up >> > to a full PRI worth of Iaxmodems. >> >> Then you have probably seen that YMMD, and that some people claim >> great success with VoIP fax. >> >> Other people claim that the only way to go is a hardware fax solution, >> like the dedicated multi-modem fax cards. >> >> The only way you're going to find a solution that will work for you is >> to try it, scale it, build your own expertise with your solution, load >> test it, and watch your error rate. >> > > I certainly understand the value of building the solution, testing, > patching, and fixing problems as they arise. It was my hope however > that others would have large-scale experience with these technologies > and could share some pointers. > > I'm about to perform some bulk testing between two servers to see how > the system reacts. I'm more than happy to post my findings here if > anyone has interest. > >> The other consideration is your budget and your cost of dropping a >> fax. The faxmodem cards are not cheap compared to a voip solution. But >> if the faxes have a high value to the business the hardware cards are >> probably justified. >> >> Again, you'll find people arguing that their voip solution has as low >> of a failure rate as a hardware solution. I'm jealous. My voip fax >> solution does not yet have that low of a failure rate, but I'm >> hopefully getting closer to working out the last bugs. >> > > Do you have any specifics to share about the problems you're finding? > >> > I've also noticed that IAXmodem is compiled statically against a version >> > of >> > spandsp included with the iaxmodem source. For a large installation, >> > would >> > it be better to compile iaxmodem dynamically to reduce the per-instance >> > size >> > of each iaxmodem? Or, would it be better to simply throw more RAM at it? >> >> I'm not sure what difference RAM makes. What breaks a fax on voip is >> latency and dropped packets. > > Agreed. I was simply inquiring about the efficiency of IAXmodem at the > system resource level. Latency and packet drops will be minimal or > nonexistent at all in this environment. > >> >> You solve both of those problems if you go the hardware solution route >> with a faxmodem card. >> > > I've found hardware fax boards aren't a 100% fix either. Many of the > boards are buggy. However, I will have to say that certain > manufacturers like Mainpine are near 100%. > >> The in-between solution is using a proprietary telco -> fax gateway, >> like a Cisco box that terminates a PRI and provides FXO ports that you >> plug into a single-pair faxmodem or a 'real' fax machine. That >> solution quickly becomes ridiculous when you try to scale it. >> >> > Are there any concurrency issues when receiving a large number of faxes >> > on a >> > system using IAXmodems? >> >> File system contention, but fax files aren't very large, and I would >> call that a non-issue. Most people don't want a piece of paper; they >> want a PDF that they can turn into paper once in a while. >> > > The purpose of such a system as I'm inquiring about is for digital > archival. Very little 'paper' will be in use. Buffering aside, each > fax could be written at the speed at which it is received correct? So, > if I'm receiving 50 faxes at 14.4kbps each, assuming a direct receive > frame-->block write, I'd be looking at roughly 90KBps written to disk. > Is my logic sound here? > > Thank you for the response and ideas. > > Marshall > > _______________________________________________ > -- Bandwidth and Colocation Provided by http://www.api-digital.com -- > > asterisk-users mailing list > To UNSUBSCRIBE or update options visit: > http://lists.digium.com/mailman/listinfo/asterisk-users > -- Sent from my mobile device _______________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users