Re: [Sip-implementors] Query related to OPTIONS
sunil.bha...@wipro.com wrote: > Hi, > > Say, UAS doesn't have any endpoint configured and will not be able to handle > calls. In this case, should the UAS send a 4xx response, say 408 timeout, > when it receives OPTIONS request, or is it better to ignore the incoming > OPTIONS request and not send any response to it? Returning no response at all is an *exceedingly* bad choice. It will result in the requester retrying and so take a long time to fail. Almost anything else would be better, but 408 is nearly as bad. You say it is a UAS, but can't handle calls. Do you mean it can't handle calls *now*? (E.g. it is a "pbx" implemented as a B2BUA that may at a later time be able to handle calls when it has some extensions connected.) Or do you mean it will *never* be able to handle calls, suas would be the case for an event server that only handles SUBSCRIBE and NOTIFY?? IMO OPTIONS was specified poorly when it called for returning the same response that an INVITE would, because it doesn't recognize all these kinds of cases. I believe many devices will respond with 200 to OPTIONS regardless of what they would do for an INVITE. So you might consider doing that - returning 200. If you can *never* support INVITE, just omit it from the Allow header. If you really want to return an error, 480 might suit this situation - that is typically what a proxy would return to an invite if there were currently no registrations. Thanks, Paul > Regards, > Sunil > > -Original Message- > From: Iñaki Baz Castillo [mailto:i...@aliax.net] > Sent: Thursday, November 12, 2009 8:03 PM > To: Sunil Bhagat (WT01 - Telecom Equipment) > Cc: sip-implementors@lists.cs.columbia.edu > Subject: Re: [Sip-implementors] Query related to OPTIONS > > 2009/11/12 : >> Hi, >> >> I have a small query regarding OPTIONS method in SIP. >> As per RFC 3261, OPTIONS is used to query a user agent or server about >> its capabilities and discover its current availability. >> >> Say, I have a SIP server which controls several endpoints, but none of >> them is up. Now I receive an OPTIONS message from the NETWORK. >> So, what should the reply from my server be? Should the SIP server send >> 200 OK response with its capabilities and availability? Or should it >> send some 4XX or 6XX response indicating that endpoints are down? > > I would suggest you to forget the theoretical usage of OPTIONS as it's > not a robust "feature" (imagine there is parallel forking so you just > receive the response from one of the branches). > > However the behavior you mean is more designed to work with endpoints. > This is, I send an OPTIONS to a phone and it replies me 200 if it's > available to receive an INVITE, 486 if it has all its lines in use, > 480 if it has set DND and so... > > But I don't expect the same behaviour in a server/b2bua/gateway as the > server/b2bua/gateway cannot know which response it will receive when > forwarding a call. > > IMHO nowadays OPTIONS is just used to mantain the NAT keepalive and to > check if a server/endpoint is alive (regardless of the response it > replies for that OPTIONS). > > > ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
Re: [Sip-implementors] Query related to OPTIONS
Hi, Say, UAS doesn't have any endpoint configured and will not be able to handle calls. In this case, should the UAS send a 4xx response, say 408 timeout, when it receives OPTIONS request, or is it better to ignore the incoming OPTIONS request and not send any response to it? Regards, Sunil -Original Message- From: Iñaki Baz Castillo [mailto:i...@aliax.net] Sent: Thursday, November 12, 2009 8:03 PM To: Sunil Bhagat (WT01 - Telecom Equipment) Cc: sip-implementors@lists.cs.columbia.edu Subject: Re: [Sip-implementors] Query related to OPTIONS 2009/11/12 : > Hi, > > I have a small query regarding OPTIONS method in SIP. > As per RFC 3261, OPTIONS is used to query a user agent or server about > its capabilities and discover its current availability. > > Say, I have a SIP server which controls several endpoints, but none of > them is up. Now I receive an OPTIONS message from the NETWORK. > So, what should the reply from my server be? Should the SIP server send > 200 OK response with its capabilities and availability? Or should it > send some 4XX or 6XX response indicating that endpoints are down? I would suggest you to forget the theoretical usage of OPTIONS as it's not a robust "feature" (imagine there is parallel forking so you just receive the response from one of the branches). However the behavior you mean is more designed to work with endpoints. This is, I send an OPTIONS to a phone and it replies me 200 if it's available to receive an INVITE, 486 if it has all its lines in use, 480 if it has set DND and so... But I don't expect the same behaviour in a server/b2bua/gateway as the server/b2bua/gateway cannot know which response it will receive when forwarding a call. IMHO nowadays OPTIONS is just used to mantain the NAT keepalive and to check if a server/endpoint is alive (regardless of the response it replies for that OPTIONS). -- Iñaki Baz Castillo Please do not print this email unless it is absolutely necessary. The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments. WARNING: Computer viruses can be transmitted via email. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email. www.wipro.com ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
Re: [Sip-implementors] Query related to OPTIONS
2009/11/12 : > Hi, > > I have a small query regarding OPTIONS method in SIP. > As per RFC 3261, OPTIONS is used to query a user agent or server about > its capabilities and discover its current availability. > > Say, I have a SIP server which controls several endpoints, but none of > them is up. Now I receive an OPTIONS message from the NETWORK. > So, what should the reply from my server be? Should the SIP server send > 200 OK response with its capabilities and availability? Or should it > send some 4XX or 6XX response indicating that endpoints are down? I would suggest you to forget the theoretical usage of OPTIONS as it's not a robust "feature" (imagine there is parallel forking so you just receive the response from one of the branches). However the behavior you mean is more designed to work with endpoints. This is, I send an OPTIONS to a phone and it replies me 200 if it's available to receive an INVITE, 486 if it has all its lines in use, 480 if it has set DND and so... But I don't expect the same behaviour in a server/b2bua/gateway as the server/b2bua/gateway cannot know which response it will receive when forwarding a call. IMHO nowadays OPTIONS is just used to mantain the NAT keepalive and to check if a server/endpoint is alive (regardless of the response it replies for that OPTIONS). -- Iñaki Baz Castillo ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
