At 12:06 PM 8/16/2004, Arnd Vehling wrote:
Jiri Kuthan wrote:
Now to provide a complete answer to the question: the values are supposed to be unique according to RFC3261 but there is nothing in the world that prevents broken implementations to generate invalid non-unique values. There are indeed implementations that are broken. To make CDRs as much unique as you can, compose the identifier as a triple callid-fromtag- totag. Composition of values generated by UACs and UASs significantly reduces the chance of not being unique.
Why does the formulation "significantly reduces the chance of not being unique" make me nervous? :)
I don't know, I am not a psychologist ;)
May it be that the "SIP RFC Fathers" neglected the real-word issue of actually accounting sip-calls a bit? Making accounting dependant on client side software implementations doesnt seem a basicly good idea to me.
That's why RFC3261 identifies dialog by the triple, which includes server-generated to-tag. Obviously if clients and servers agree to generate stupid triple {from-tag, callid, to-tag}, accounting can still mess, but I don't see this case as a huge issue.
-jiri