SIP is an extensible, open-standard protocol which is becoming the
de-faco standard for VoIP calls. SS7 and Q.931 (used in this question
as examples) are telephony protocols used for the routing of ordinary
phone calls over IDSN lines.
The tleephony protocols contain information about the call such as the
calling party (the CLI), the number dialled (the DDI) and then many
and various settings, indicators and flags. Many of these flags are
protocol-specific. I'll use an SS7 flag as an example:
CPC: Calling party category
Example value: "1: Ordinary, (Residential)",
Default value: "0: Unknown"
We have a requirement to receive a call from a telco on an SS7 link,
pass it through our VoIP network and pass it back out on another SS7
link. It is a requirement of the telco that when we route a call in
this way, the resulting call has the same settings as the original
one.
My question is this: What standards, naming schemes or other
agreements are there on the transmission of such protocol-specific
data in a SIP VoIP call? Where can I read about them?
It's possible that you might get lucky and find there's an RFC exactly
on this topic, and I've been too lazy to find it. :-) |
