Re: [Sip-implementors] Request-URI of ACK

2013-02-11 Thread Alok 2 Tiwari
Hi Jānis, The ACK can have the different request URI if the 200 OK of INVITE contains an strict router address in Record-Route header. The proxy modifies the Request-URI of ACK only if the next hope is a strict router. Regards, Alok Tiwari Aricent -Original Message- From: sip-implement

Re: [Sip-implementors] Registrar / Presence Server receives SIP message without Max-Forwards Header

2013-01-03 Thread Alok 2 Tiwari
Hi Keerthi, The Max-Forwards header field is used with any SIP method to limit the number of proxies or gateways that can forward the request to the next downstream server. Since Registrar/Presence server are acting as end point for the SIP messages, Max-Forwards header is not mandatory. Re

Re: [Sip-implementors] What will be set in Request-URI with respect to loose and strict routing

2012-11-14 Thread Alok 2 Tiwari
emote address from Request URI will be set as strict router in Route header. Regards, Alok Tiwari Aricent From: Vivek Gupta [mailto:vivek.gu...@globallogic.com] Sent: Thursday, November 15, 2012 10:41 AM To: Pranab Bohra Cc: Alok 2 Tiwari; Vivek Batra; sip-implementors@lists.cs.columbia.edu Subjec

Re: [Sip-implementors] What will be set in Request-URI with respect to loose and strict routing

2012-11-06 Thread Alok 2 Tiwari
Hi Vivek, In first case, request URI will be set as 'sip:1...@abc.com' and Route header will have 'sip:proxy2.com' as loose router. In second case, request URI will be set as 'sip:proxy2.com' and Route header will have 'sip:1...@abc.com' as strict router. Regards, Alok Tiwari Aricent -Origin

Re: [Sip-implementors] Is contact header mandatory for each sip messages?

2012-11-06 Thread Alok 2 Tiwari
Hi Tamjid, As per RFC-3261, Contact is optional in 1xx but it is mandatory in 2xx. Refer table in section 20.1. Header field where proxy ACK BYE CAN INV OPT REG ___ Contact R

Re: [Sip-implementors] Help understanding trace

2012-11-04 Thread Alok 2 Tiwari
Hi Antonio, 200 OK of INVITE contains the multiple Record-Route headers. All subsequent requests from UAC should follow the path as mentioned in Record-Route header and Address in contact header should be the final destination. In the mentioned scenario, 200 OK have the following Record-Route

Re: [Sip-implementors] ask for PRACK omitting Require:100rel

2012-09-03 Thread Alok 2 Tiwari
Hi Manolis, UAS cannot ask for a PRACK without "Require:100rel". Also RSeq is used in 1xx provisional response only. Please refer the following sections in RFC-3262. 3 UAS Behavior The provisional response to be sent reliably is constructed by the UAS core according to the procedures of S

Re: [Sip-implementors] query in sip

2012-05-10 Thread Alok 2 Tiwari
Hi Pranab, As per RFC 3261- section 12.2.1.1 Generating the Request Requests within a dialog MUST contain strictly monotonically increasing and contiguous CSeq sequence numbers (increasing-by-one) in each direction (excepting ACK and CANCEL of course, whose numbers equal the requests bein

Re: [Sip-implementors] issue in sip

2012-05-07 Thread Alok 2 Tiwari
Hi Pranab, As per RFC-3261, section 12.2.1.1, If the local sequence number is not empty, the value of the local sequence number MUST be incremented by one, and this value MUST be placed into the CSeq header field. If the local sequence number is empty, an initial value MUST be chosen us

Re: [Sip-implementors] npdi parameter in sip: scheme URIs

2012-04-11 Thread Alok 2 Tiwari
Hi Alex, "npdi" is a parameter in Request URI. So it neither can appear in the user part nor in the domain part. It will appear as a uri-parameter as per following grammar. Request-Line= Method SP Request-URI SP SIP-Version CRLF Request-URI = SIP-URI / SIPS-

Re: [Sip-implementors] Proxy and Registrar behavior for the Unknown URI schema in From, To, Contact and Request URI

2012-04-11 Thread Alok 2 Tiwari
Hi Keerthi, For all the SIP entities, Basic SIP rules are same. IMO, In these cases, Proxy and Registrar should send 416 "Unsupported URI Scheme". Regards, Alok Tiwari Aricent -Original Message- From: sip-implementors-boun...@lists.cs.columbia.edu [mailto:sip-implementors-boun...@lists

Re: [Sip-implementors] Doubt reagrding CALL-ID host part of SIP request

2012-03-11 Thread Alok 2 Tiwari
Hi Manju, As per grammar defined in RFC-3261, syntax for Call-ID is as follows: Call-ID = ( "Call-ID" / "i" ) HCOLON callid callid = word [ "@" word ] word= 1*(alphanum / "-" / "." / "!" / "%" / "*" / "_" / "+" / "`" / "'" / "~" / "("

Re: [Sip-implementors] Reg via header in CANCEL request

2012-03-06 Thread Alok 2 Tiwari
Hi Rajanagam, AS per Section: 9.2, RFC-3261, 9.2 Server Behavior The CANCEL method requests that the TU at the server side cancel a pending transaction. The TU determines the transaction to be cancelled by taking the CANCEL request, and then assuming that the request method is anyth

Re: [Sip-implementors] Direct communication in SIP

2010-11-15 Thread Alok 2 Tiwari
Hi Tabt, In SIP, when receiving an INVITE request, receiver sends the response of INVITE at address received in via header of INVITE. The Contact in INVITE is used by receiver to send the subsequent request directly to the SIP end point after call establishment. Thanks, Alok Tiwari Aricent -

Re: [Sip-implementors] SDP Offer ANswer

2010-11-02 Thread Alok 2 Tiwari
Refer RFC-3261, section-13.2.1: "If the initial offer is in an INVITE, the answer MUST be in a reliable non-failure message from UAS back to UAC which is correlated to that INVITE." In your scenario, since Terminating SIP does not support 100 Rel and answer SDP is received in unreliable 180,

Re: [Sip-implementors] UA sending REGISTE Reqeust with Route header

2010-09-02 Thread Alok 2 Tiwari
Hi Siddhardha, Please refer the table mentioned in RFC-3261 section-20. Thanks, Alok Tiwari Aricent -Original Message- From: sip-implementors-boun...@lists.cs.columbia.edu [mailto:sip-implementors-boun...@lists.cs.columbia.edu] On Behalf Of Siddhardha Garige Sent: Friday, September 03,

Re: [Sip-implementors] Invite without SDP

2010-08-18 Thread Alok 2 Tiwari
Hi Manoj, To hold a call, UA should send the SDP in INVITE. Other party can put the call on hold based on media change in SDP. If SDP is not present in INVITE, other party must send the SDP in 200 OK as a new offer and UA should send the answer SDP in ACK. Thanks, Alok Tiwari Aricent -Orig

Re: [Sip-implementors] RFC 3261, 100 Trying on Re-Invite

2010-07-26 Thread Alok 2 Tiwari
Hi Mia, IMO, it would be better to implement a new timer to handle such scenario. This timer should be stopped if any final response of Re-INVITE is received. In case of timer expiry, terminate the dialog. The timer duration should be greater than Timer-B. Thanks, Alok Tiwari Aricent -Orig

Re: [Sip-implementors] SDP offer-answer - problem

2010-05-04 Thread Alok 2 Tiwari
Hi Michael, Static codec: Static codecs have the defined payload number for a particular codec. Therefore, the use of a=rtpmap attribute for static payloads is optional. Dynamic codec: Dynamic payload types are in range of 96-127. Payloads in this range do not refer to a particular codec; inste

Re: [Sip-implementors] What is wrong with that regisster

2010-04-19 Thread Alok 2 Tiwari
Hi Nahum, The REGISTER request submitted after receiving the 401 response should contain the "Authorization" header with authentication credentials. Sever will authorize the REGISTER request based on the authentication credentials received in "Authorization" header. Please refer RFC-3261 sect

Re: [Sip-implementors] transport param in uri with sips scheme

2010-04-19 Thread Alok 2 Tiwari
Hi Chozhan, SIPS allows resources to specify that they should be reached securely. It mandates that each hop over which the request is forwarded up to the target domain must be secured with TLS. Therefore, SIPS uri scheme can used only in case of TLS but SIP URI can be used in any transport mod

Re: [Sip-implementors] What's the difference between session and dialog in SIP?

2010-03-04 Thread Alok 2 Tiwari
Hi Amar, A dialog is a peer-to-peer SIP relationship between two user agents that persists for some time. The dialog facilitates sequencing of messages and proper routing of requests between the user agents. Adialog is identified by a call identifier, local tag, and a remote tag. A session is

Re: [Sip-implementors] Check Allow header before sending INFO message?

2010-02-08 Thread Alok 2 Tiwari
Hi Elison, The absence of an Allow header field MUST NOT be interpreted to mean that the UA sending the message supports no methods. Rather, it implies that the UA is not providing any information on what methods it supports. Refer RFC-3261 section: 20.5 Thanks, Alok Tiwari Aricent -Origi

Re: [Sip-implementors] Who may send '407 Proxy Authenticate Response' ?

2010-02-08 Thread Alok 2 Tiwari
Hi, Proxy can challenge the UA by sending the '407 Proxy Authenticate Response'. Please refer the following section in RFC-3261. 21.4.8 407 Proxy Authentication Required This code is similar to 401 (Unauthorized), but indicates that the client MUST first authenticate itself with

Re: [Sip-implementors] 481 Call/Transaction does not exist on BYE

2010-02-01 Thread Alok 2 Tiwari
Hi Antoine, The BYE request contains the two semicolon (;) before the To-tag. Retry the scenario after removing one extra semicolon before To-tag. Thanks, Alok Tiwari Aricent -Original Message- From: sip-implementors-boun...@lists.cs.columbia.edu [mailto:sip-implementors-boun...@lists.c

Re: [Sip-implementors] 407 Authentication failure

2010-01-14 Thread Alok 2 Tiwari
Hi Josep, When a request is challenged with 407 (containing proxy-authenticate header), the request should be re-submitted with proxy-authorization header. Please refer the following section is RFC-3261: 22.3 Proxy-to-User Authentication Similarly, when a UAC sends a request to a prox

Re: [Sip-implementors] Re-Invite before ACK send/received

2010-01-05 Thread Alok 2 Tiwari
Hi Zabi, INVITE and Re-INVITE are different transactions. 200 OK for INVITE and Re-INVITE will have the different CSeq value and Branch parameter in Via header. UA should send the same ACK for INVITE after receiving 200OK. Thanks, Alok Tiwari Aricent -Original Message- From: sip-implem

Re: [Sip-implementors] Query regarding implementation of Outbound during Incoming Call

2009-12-21 Thread Alok 2 Tiwari
Hi Vivek, Outbound proxy is only used while making an outgoing call. In case of incoming call, the responses are sent on via and after call is established, the SIP messages should be send to SIP contact or record-route. Thanks, Alok Aricent -Original Message- From: sip-implementors-bou

Re: [Sip-implementors] differences between Via, Record-Route and Route headers

2009-12-09 Thread Alok 2 Tiwari
Hi Manoj, Via is used to route responses whereas Route and Record-Route headers are used to route requests. User agents use Record-Route headers to build Route headers. The other routing related headers are Path header (Refer RFC-3327) and service-route header (Refer RFC-3608). Thanks, Alok Ti

Re: [Sip-implementors] ACK received at UAS out of dialog

2009-10-27 Thread Alok 2 Tiwari
Hi Anna, The ACK should be ignored. An ACK is only sent in response to a response to an INVITE request. Thanks, Alok Tiwari Aricent -Original Message- From: sip-implementors-boun...@lists.cs.columbia.edu [mailto:sip-implementors-boun...@lists.cs.columbia.edu] On Behalf Of Gellatly, Ann

Re: [Sip-implementors] Why ACK is Seperate transaction?

2009-10-16 Thread Alok 2 Tiwari
Hi Sharan, ACK is the separate transaction only when INVITE is responded with 2xx response. Please refer the section-17 in RFC-3261. 17 Transactions SIP is a transactional protocol: interactions between components take place in a series of independent message exchanges. Specifically, a

Re: [Sip-implementors] Redirect 3xx Response

2009-10-07 Thread Alok 2 Tiwari
Hi Jon, Requests other than CANCEL can receive a 3xx response. Please refer the "section 8.3 Redirect Servers" in RFC-3261: "A redirect server does not issue any SIP requests of its own. After receiving a request other than CANCEL, the server either refuses the request or gathers th

[Sip-implementors] security association if REGISTER is challenged by proxy with security-server header in 407.

2009-03-30 Thread Alok 2 Tiwari
Hi, As per spec 3GPP TS 24.229 V8.0.0 section: 5.1.1.5.1 Authentication is performed during initial registration. A UE can be re-authenticated during subsequent reregistrations, deregistrations or registrations of additional public user identities. When the network requires authentication or r

Re: [Sip-implementors] Query regarding Retry-After timers in 491response in glare situation

2008-10-17 Thread Alok 2 Tiwari
Hi, As per RFC-3261, the retry after timer is started by UAC itself after deciding the retry after duration based on call id ownership. So there is no need of retry after header in 491 response code. But since your implementation is as below: I am adding the party name to make you understand t