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urisiprfc

Is more than one instance of tag in a SIP user valid?

I'm writing some code to parse SIP users (From:/To: headers) and I ran into a case that threw an exception in my code:

From: "1000"<sip:1000@192.99.32.105>;tag=313030300131333539323834383930;tag=4e6f6e650132363237343735343432

There are two instances of tag. I can't understand clearly from the RFC if it is valid to have multiple tag parameters in the uri. Does anyone know?

Solution

  • No, that's not allowed. RFC3261 section 7.3.1 states:

    Even though an arbitrary number of parameter pairs may be attached to a header field value, any given parameter-name MUST NOT appear more than once.