Benoit Panizzon
2018-Mar-19 15:53 UTC
[asterisk-users] Is 100 trying mandatory? Can asterisk answer with 180 without prior 100 trying?
Hey List I sometimes use our asterisk server to do some debugging or other PBX and SBC. Now we have a case where a PBX is replying an incomming invite with 180 ringing immediately. It looks like the SBC does not accept this. According to my understanding of the RFC 3261 any provisional (aka 1XX) reply should be good enough to make the sender stop re-sending invites and accept this as a reply from the destination. So 100 trying would be option and a reply could also be directly 180 ringing. So maybe some RFC specialist could tell me how this is exactly supposed to work of if I maybe missed some other RFC more clear about that topic. To try to reproduce the problem with our SBC, is there a way to tell the asterisk, preferably PJSIP, to directly answer with 180 ringing without prior 100 trying? Mit freundlichen Gr?ssen -Beno?t Panizzon- -- I m p r o W a r e A G - Leiter Commerce Kunden ______________________________________________________ Zurlindenstrasse 29 Tel +41 61 826 93 00 CH-4133 Pratteln Fax +41 61 826 93 01 Schweiz Web http://www.imp.ch ______________________________________________________
Joshua Colp
2018-Mar-19 15:59 UTC
[asterisk-users] Is 100 trying mandatory? Can asterisk answer with 180 without prior 100 trying?
On Mon, Mar 19, 2018, at 12:53 PM, Benoit Panizzon wrote:> Hey List > > I sometimes use our asterisk server to do some debugging or other PBX > and SBC. > > Now we have a case where a PBX is replying an incomming invite with 180 > ringing immediately. It looks like the SBC does not accept this. > > According to my understanding of the RFC 3261 any provisional (aka > 1XX) reply should be good enough to make the sender stop re-sending > invites and accept this as a reply from the destination. > > So 100 trying would be option and a reply could also be directly 180 > ringing.Indeed. In practice though you want to stop the retransmission immediately and you usually don't know of the appropriate response yet so 100 is sent.> > So maybe some RFC specialist could tell me how this is exactly supposed > to work of if I maybe missed some other RFC more clear about that topic. > > To try to reproduce the problem with our SBC, is there a way to tell > the asterisk, preferably PJSIP, to directly answer with 180 ringing > without prior 100 trying?The PJSIP channel driver has no option or ability to do this. I do not recall if chan_sip does. -- Joshua Colp Digium, Inc. | Senior Software Developer 445 Jan Davis Drive NW - Huntsville, AL 35806 - US Check us out at: www.digium.com & www.asterisk.org
Daniel Tryba
2018-Mar-20 11:21 UTC
[asterisk-users] Is 100 trying mandatory? Can asterisk answer with 180 without prior 100 trying?
On Mon, Mar 19, 2018 at 12:59:47PM -0300, Joshua Colp wrote:> > To try to reproduce the problem with our SBC, is there a way to tell > > the asterisk, preferably PJSIP, to directly answer with 180 ringing > > without prior 100 trying? > > The PJSIP channel driver has no option or ability to do this. I do not recall if chan_sip does.A (very) dirty workaround would be to drop these packets with iptables (assuming Linux as OS), something like: iptables -t raw -I OUTPUT -p udp -d ipaddrofpbx -m string --algo bm --from 0 --to 32 --string "SIP/2.0 100 " -j DROP Don't try it with TCP :)