[Users] Re: [Serusers] Help with MySQL acc query

Jan Janak jan at iptel.org
Tue Nov 1 21:51:49 CET 2005

On 01-11-2005 15:41, Evan Borgstrom wrote:
> Daniel-Constantin Mierla wrote:
> >On 11/01/05 20:46, Evan Borgstrom wrote:
> >>
> >>    If a UA doesn't change it's call id on every new transaction or it 
> >>reuses call id's then drop support for the UA in your network and tell 
> >>the vendor to fix their broken implementation. I'm tired of seeing 
> >>little kludges to deal with one or two broken vendors.
> >>Section of RFC 3261:
> >>
> >>   In a new request created by a UAC outside of any dialog, the Call-ID
> >>   header field MUST be selected by the UAC as a globally unique
> >>   identifier over space and time unless overridden by method-specific
> >>   behavior.  All SIP UAs must have a means to guarantee that the Call-
> >>   ID header fields they produce will not be inadvertently generated by
> >>   any other UA.
> >Here is where the problem usually occurs. Most of the UA I have seen 
> >relies on IP address to fulfill this requirement, but this fails in the 
> >case of private addresses. Usually, the call id is in the form of 
> >"some_hash at ip".
> 	How would the UA having a RFC1918 IP address cause it fail? It's 
> 	still a valid address it's just not routable, besides it's the part before 
> @ip that's really important. md5(time() + my_mac_address) will give you a 
> "unique identifier over space and time" so there's no excuse for reusing 
> or not generating unique call-id's.

  Right, if you can determine current time. This is not always the case,
  you can have a phone that was rebooted and has neither internal clock
  nor access to NTP. 


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