>>1. Why always Escaped header should be preceded by question mark(?).
This is not exactly the case. the first header is preceded by a ? subsequent headers ar from rfc3261 BNF headers = "?" header *( "&" header ) header = hname "=" hvalue hname = 1*( hnv-unreserved / unreserved / escaped ) hvalue = *( hnv-unreserved / unreserved / escaped ) hnv-unreserved = "[" / "]" / "/" / "?" / ":" / "+" / "$"e preceded by a & >>2. What is the significance of Escaped Header. stuff after a question mark are extra headers needed in the the new request to be sent out. >>3. Is there any information on usage of Escaped Header. there are mentions of escaped characters in rfc3261 and usage of headers in rfc3515. >>4. Examples of Escaped headers. Replaces is a header used to replace an existing call (see RFC3891 for details) Normally it looks a bit like this: Replaces: [email protected];to-tag=7743;from-tag=6472 Well, in some cases you want to REFER someone to somewhere and replace an existing call. So you send would want to send out a REFER with: Refer-To: [email protected][email protected];to-tag=7743;fro m-tag=6472 but you can't because the special characters have to be escaped. You have to escape the @ and ; and = Refer-To: [email protected]?replaces=425928%40phone.example.org%3bto-tag%3d77 43%3Bfrom-tag%3D6472 >>5. What is the usage of Escaped header in SIP Application. It's often used in call transfer http://www.ietf.org/rfc/rfc3515.txt there are examples in section 2.1 Regards, Attila -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of jafer sharif mohammed Sent: 05 February 2009 09:38 To: [email protected] Subject: [Sip-implementors] Escaped Header Hi All, Can anyone please clarify the below points: 1. Why always Escaped header should be preceded by question mark(?). 2. What is the significance of Escaped Header. 3. Is there any information on usage of Escaped Header. 4. Examples of Escaped headers. 5. What is the usage of Escaped header in SIP Application. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
