The basic answer is that SIP is based upon HTTP as indicated within RFC 3261 section 7 and 7.3. Thus there is some flexibility to accommodate messages that are formatted for human consumption. Similarly, RFC 3966 allows visual separators for easier human consumption.
"Except for the above difference in character sets, much of SIP's message and header field syntax is identical to HTTP/1.1. Rather than repeating the syntax and semantics here, we use [HX.Y] to refer to Section X.Y of the current HTTP/1.1 specification (RFC 2616 [8])." "SIP header fields are similar to HTTP header fields in both syntax and semantics. In particular, SIP header fields follow the [H4.2] definitions of syntax for the message-header and the rules for extending header fields over multiple lines. However, the latter is specified in HTTP with implicit whitespace and folding. This specification conforms to RFC 2234 [10] and uses only explicit whitespace and folding as an integral part of the grammar." > -----Original Message----- > From: [email protected] [mailto:sip- > [email protected]] On Behalf Of Sachin Rastogi > Sent: Wednesday, April 17, 2013 2:21 AM > To: Brett Tate; [email protected] > Cc: Sumant Gupta > Subject: Re: [Sip-implementors] Query regarding ABNF syntax for SIP > message headers > > Hi All, > As discussed below > > > Via: \r\n > > SIP/2.0 \r\n > > /[transport] > [local_ip]:[local_port];branch=[branch]\r\n > > is valid as per ABNF. What is the reasoning behind defining CRLF as > part of > HCOLON ? Why it is allow by rfc 3261 to send someone **via** like above > with CRLFs ? Please share any usecase scenario. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
