2 Feb
2004
2 Feb
'04
6:06 p.m.
Hi,
Am Monday 02 February 2004 23:48 schrieb Balaji Bapulal Thoguluva:
I am writing a software to parse SIP messages. I
have couple of
questions that I would like to clarified.
maybe your questions are better placed at the SIP mailing lists.
1. How to recognise if a packet is a SIP or a non-SIP
packet?. SIP uses
TCP, UDP as underlying transport.
How to recognise that a request is a HTTP request or not? Parse it! If you can
parse it, it is a valid request of that protocol. If you fail it is probably
not a valid request (or your parser is faulty).
2. How to know the direction of the SIP message if it
is from SIP proxy or
from SIP client?. I ask this question because in most of the SIP messages,
the header fields are copied from previous messages and so the from, To
header fileds doesn't always signify he direction
If you dont know if the IP/host is a proxy or a UA i dont know a safe way to
determine if the type/class of the device.
3. Can Call-ID be used to find the number of distinct
phone call taken
place between different SIP UA's?.
No. The content of the Call-ID depends on the UA implementation and e.g. can
be randomly.
4. What is the significance of dialog-ID? and how can
it be used?
AFAIK it's the internal identifier of an UA for one dialog state. This can be
equal to the To or From tag, but can also be something completely different.
Regards
Nils