> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> Sent: Friday, May 11, 2001 12:33 AM
> To: [EMAIL PROTECTED]
> Subject: [Sip-implementors] lots of doubt..plz help
>
>
> hi all,
> i am trying to design a SIP proxy according to
> RFC2543 (24 nov).
> i have the following doubts.. :(
>
> 1) What are the tools used to implement SIP
> parser.
Many people write them by hand. Others use automatically generated parsers
from the grammar.
> 2) Is it UTF-8 encoding and decoding really
> necessary.
For a proxy, not really. All of the keywords that have semantic meaning are
in ASCII. Things like the value of the Subject header can contain non-ASCII
characters. But, proxies don't care what the value of the SUbject header is.
So, just place the value into a string. It doesn't matter that a character
spans multiple bytes.
> 3) Where can i get detailed UTF-8 decoding &
> encoding algorithms.
Java handles it, I believe, but its not needed anyway.
> 4) Is the decription should be done before
> parsing or after parsing.
You mean decryption? You would take the body, decrypt it, and then parse it.
It makes no sense to parse something thats encrypted.
> 5) Once the user is registerd for a proxy, is
> there any method to cancel the registration.
The user can send a REGISTER with Contact:* and Expires:0 to cancel all
registrations. A server can delete a registration at any time without
announcement.
> 6) how to make The client server model used in
> proxy (Tranceiver) to switch between UDP and TCP.
A proxy can issue a redirect response that points to a different transport.
For example, a request for sip:[EMAIL PROTECTED] might look like:
INVITE sip:[EMAIL PROTECTED] SIP/2.0
Via: SIP/2.0/UDP mypc.bar.com
and then the proxy returns:
SIP/2.0 305 Switch to TCP
Contact: sip:[EMAIL PROTECTED];transport=TCP
if the client is TCP capable, it then does:
INVITE sip:[EMAIL PROTECTED];transport=tcp SIP/2.0
Via: SIP/2.0/TCP mypc.bar.com
which is sent over TCP.
> 7) Should the SIP proxy be dedicated to a
> Transaction?
A useful sip proxy will probably want to handle more than one transaction.
> 8) Should the billing part be handled by
> location server application?
How billing is done depends on what you want to bill for, and is not
specified within SIP.
-Jonathan R.
---
Jonathan D. Rosenberg, Ph.D. 72 Eagle Rock Ave.
Chief Scientist First Floor
dynamicsoft East Hanover, NJ 07936
[EMAIL PROTECTED] FAX: (973) 952-5050
http://www.jdrosen.net PHONE: (973) 952-5000
http://www.dynamicsoft.com
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