[SIPForum-discussion] help on From header

[XIAO Xiaohong]

Rout,
Thank you. Yes, user=phone is present, so pre-@ part must be digit numbers.
But, the reason is not you mentioned "not using tel-uri".
According to rfc 3261 section 19.1.3 Example SIP and SIPS URIs:
sip:+1-212-555-1212:1234 at gateway.com;user=phone
In this example, it is a SIP URI, not TEL-URI.
 
Now I understand why following header is not valid. 
From:Anonymous<sip:Anonymous at anonymous.invalid;user=phone>;tag=F4363246313536415576E403

 
The evidence is still in rfc3261. It says:
              /*The set of valid telephone-subscriber strings is a subset of 
         valid user strings.  The user URI parameter exists to 
         distinguish telephone numbers from user names that happen to 
         look like telephone numbers.  If the user string contains a 
         telephone number formatted as a telephone-subscriber, the user 
         parameter value "phone" SHOULD be present.  Even without this 
         parameter, recipients of SIP and SIPS URIs MAY interpret the 
         pre-@ part as a telephone number if local restrictions on the 
         name space for user name allow it.*/  
 
 
According to above words, we can say:   
1.   telephone-subscriber strings are only digits like "12345"
2.   user name can be digits like "12345", or like "Alice"
3.  "user=phone" is used to DISTINGUISH telephone numbers from user names. 
   If "user=phone" present, it means pre-@ part is a  telephone-subscriber strings, i.e. it must be digits like  "12345".
   if "user=phone" is not present, but per-@ part is a  digits string for example  "12345",  the device who receiving this URI can regard it as a telephone-subscriber if its local policy allowes it, 4. some examples:
12345 at abc.com; user=phone             ====> correct,  the device who decoding this URI regard this as a telephone-subscriber
12345 at abc.com;     ====>  correct, the device decoding this URI can regard it as a telephone-subscriber, or just regard it as a normal user name     
Alice at abc.com; user=phone                  ====> not correct, it takes "user=phone", but  per-@ par is not a telephone-subscriber. 
Alice at abc.com                                      ====> correct,  the device who decoding this URI regard this as a user name

 

________________________________

From: shiba shankar rout [mailto:rout.shibashankar at gmail.com] 
Sent: 2009年7月30日 12:21
To: XIAO Xiaohong
Cc: discussion at sipforum.org
Subject: Re: [SIPForum-discussion] help on From header


Hi Xiao,

The issue  is you  are mentioning  user=phone in the FROM header  but you are not using  tel-uri. This is the reason you got error.
As  RFC 3261 suggests  that if you are mentioning user=phone in From header then you have to mention tel-uri.
For example:

Thanks.
S S Rout




On Wed, Jul 29, 2009 at 6:48 AM, XIAO Xiaohong <Xiaohong.Xiao at alcatel-sbell.com.cn> wrote:


	Hello,
	 
	Could somebody tell me following From header is valid or not? Which rfc specified "user=phone"?
	 
	 
	From:Anonymous<sip:Anonymous at anonymous.invalid;user=phone>;tag=F4363246313536415576E403
	
	 
	
	The SIP stack in my equipment complains when it is trying to decoding above From header.
	  
	  STACK ERROR:Syntax error while parsing Tel/related
	  STACK ERROR:syntax error, unexpected ALPHAS, expecting ISDNTAG or EXTENSIONTAG or PHONETAG
	 
	 
	If we change the From header to
	 From:Anonymous<sip:Anonymous at anonymous.invalid>;tag=F4363246313536415576E403
	 
	Then everything is OK.
	 
	 
	Thank you.
	 
	
	


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