[Serusers] From-Tag/Call-id not uniq?

Klaus Darilion klaus.mailinglists at pernau.at
Thu Aug 12 18:31:45 CEST 2004


For IP-PSTN calls:
If you "bad" implemented UAs which use the same call-id and from-tag in 
multiple calls, you can distinguish from the to-tag, which will be 
generated by your GW and should be correct (that means different for 
each call).

regards,
klaus

Arnd Vehling wrote:
> Hi,
> 
> according to the RFC:
> 
> "When a tag is generated by a UA for insertion into a request or
>  response, it MUST be globally unique and cryptographically random
>  with at least 32 bits of randomness."
> 
> But when looking at a sip logfile:
> 
> egrep "^From:.*;tag=9d49295bb825210f" /var/log/term.log  | wc -l
> 503
> 
> Question: Did i understood something wrong or is the recoccurance of
> the same tag-id and callid in different sessions voilating the rfc?
> 
> Ive found loads of non-uniq call-ids as well as non uniq tags. How
> is a man supposed to make accounting (besides accounting on the PSTN
> GW/Voice Switch) when those to identifiers are not globally uniq?
> 
> So far ive seen non uniq callids from Grandstream Products and non uniq
> tags from sipura adapters.
> 
>    :: arnd ::
> 
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