3 Nov
2005
3 Nov
'05
2:24 a.m.
I found a situation where some SIP phones worked and some don't.
After a while I found that, because of the added bytes of the
"Proxy-Authorization:" header, the messages generated by some sip phones
were larger than 1480 bytes and this caused the connection with the PSTN
gateway to not work.
I tried to forwad the message with the t_relay_to_tcp() function, but by
the ngrep output it seems that it still uses UDP (but I may be wrong).
Anyway, what can be done in this situations?
What about a SER module that rewrite all header field names with their
compact form? Often, the message is only a few bytes more than 1480, so
this could be a solution...
What do you think?
Bye.
--
___________________________________________________
__
|- giannici(a)neomedia.it
|ederico Giannici http://www.neomedia.it
___________________________________________________
3 Nov
3 Nov
11:11 a.m.
Hi Federico,
Had the same problems. Solutions that work:
- you have somewhere MTU limit of 1500 bytes. Check where you have this
limit, it is possible you will be able to send bigger messages after changes
- use SER's consume_credentials() function to remove Authorization or
Proxy-Authorization HF after use
- configure all phones to use and describe in SDP only 1 or 2 codecs (decide
about your system codec, delete the rest from UAs)
- write your small function (in example in nathelper module) to edit SDP and
remove unused codecs when messages go through proxy
Arek,
----- Original Message -----
From: "Federico Giannici" <giannici(a)neomedia.it>
To: "SER Users" <serusers(a)lists.iptel.org>
Sent: Thursday, November 03, 2005 1:24 AM
Subject: [Serusers] Packets fragmentation and message reduction
I found a situation where some SIP phones worked and
some don't.
After a while I found that, because of the added bytes of the
"Proxy-Authorization:" header, the messages generated by some sip phones
were larger than 1480 bytes and this caused the connection with the PSTN
gateway to not work.
I tried to forwad the message with the t_relay_to_tcp() function, but by
the ngrep output it seems that it still uses UDP (but I may be wrong).
Anyway, what can be done in this situations?
What about a SER module that rewrite all header field names with their
compact form? Often, the message is only a few bytes more than 1480, so
this could be a solution...
What do you think?
5:33 p.m.
Arek Bekiersz wrote:
Hi Federico,
Had the same problems. Solutions that work:
- you have somewhere MTU limit of 1500 bytes. Check where you have this
limit, it is possible you will be able to send bigger messages after changes
- use SER's consume_credentials() function to remove Authorization or
Proxy-Authorization HF after use
- configure all phones to use and describe in SDP only 1 or 2 codecs (decide
about your system codec, delete the rest from UAs)
- write your small function (in example in nathelper module) to edit SDP and
remove unused codecs when messages go through proxy
OK, but what about the idea of rewriting all header field names using
the compact form?
It seems to me less traumatic than altering the SDP data.
Are there C functions in SER that replace a header name (and only the
name, not the value) with a different one?
Alternatively, are there C functions to find the pointer to the header
field with a given name, delete it and insert a new one?
Thanks.
----- Original Message -----
From: "Federico Giannici" <giannici(a)neomedia.it>
To: "SER Users" <serusers(a)lists.iptel.org>
Sent: Thursday, November 03, 2005 1:24 AM
Subject: [Serusers] Packets fragmentation and message reduction
--
___________________________________________________
__
|- giannici(a)neomedia.it
|ederico Giannici http://www.neomedia.it
Presidente del cda - NEOMEDIA srl
___________________________________________________
I found a situation where some SIP phones worked
and some don't.
After a while I found that, because of the added bytes of the
"Proxy-Authorization:" header, the messages generated by some sip phones
were larger than 1480 bytes and this caused the connection with the PSTN
gateway to not work.
I tried to forwad the message with the t_relay_to_tcp() function, but by
the ngrep output it seems that it still uses UDP (but I may be wrong).
Anyway, what can be done in this situations?
What about a SER module that rewrite all header field names with their
compact form? Often, the message is only a few bytes more than 1480, so
this could be a solution...
What do you think?
7:12 p.m.
Hi Federico,
1. Do you use "consume_credentials()" function in first place?
I repeat: this function removes Authorization header fields after using
them.
It can give you more than 200 bytes of margin in typical situation. It is
more than enough. What's more, you don't usually want to expose details of
your authorization
mechanism to outside world. Although we are talking about Digest
authorization scheme, it is still interesting for malicious user to know how
do you perform authorization and what are digest user names....
2. IMHO e, converting header field names to abbreviated form is actually
<more> traumatic, than editing SDP.
I rarely see UAs that use abbreviated form of SIP header fields.
--
Regards,
Arek
----- Original Message -----
From: "Federico Giannici" <giannici(a)neomedia.it>
To: "SER Users" <serusers(a)lists.iptel.org>
Sent: Thursday, November 03, 2005 4:33 PM
Subject: Re: [Serusers] Packets fragmentation and message reduction
OK, but what about the idea of rewriting all header
field names using
the compact form?
It seems to me less traumatic than altering the SDP data.
Are there C functions in SER that replace a header name (and only the
name, not the value) with a different one?
Alternatively, are there C functions to find the pointer to the header
field with a given name, delete it and insert a new one?
Thanks.
7:51 p.m.
Arek Bekiersz wrote:
Hi Federico,
1. Do you use "consume_credentials()" function in first place?
I repeat: this function removes Authorization header fields after using
them.
Yes I did.
But then I need the extra bytes to add a new Authorization header for
the next hop too!
I rarely see UAs that use abbreviated form of SIP
header fields.
Do you mean that they don't recognize the compact form?
It should be mandatory by RFC...
Bye.
--
___________________________________________________
__
|- giannici(a)neomedia.it
|ederico Giannici http://www.neomedia.it
___________________________________________________
7:55 p.m.
Hi Federico,
there are a few functions you could use.. f.eks search_reaplce, subst
etc.
check textops.
- Atle
* Federico Giannici <giannici(a)neomedia.it> [051103 18:52]:
Arek Bekiersz wrote:
Hi Federico,
1. Do you use "consume_credentials()" function in first place?
I repeat: this function removes Authorization header fields after using
them.
Yes I did.
But then I need the extra bytes to add a new Authorization header for
the next hop too!
I rarely see UAs that use abbreviated form of SIP
header fields.
Do you mean that they don't recognize the compact form?
It should be mandatory by RFC...
Bye.
--
___________________________________________________
__
|- giannici(a)neomedia.it
|ederico Giannici http://www.neomedia.it
___________________________________________________
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11:49 p.m.
Federico,
On Thursday 03 November 2005 18:51, Federico Giannici wrote:
Arek Bekiersz wrote:
from my experience I would bet that you will encounter a lot of interop
problems, when you use compact headers.
There is a lot of things mandatory in 3261, but only a very low percentage of
the devices on the market implement it, e.g. TCP, TLS, ...
Nils
I rarely see UAs that use abbreviated form of SIP
header fields.
Do you mean that they don't recognize the compact form?
It should be mandatory by RFC... 
9:20 p.m.
Hello everybody,
I have a question about the conference server. I wanted how the mixer part
is done. Specifically, how it could be implemented. For example, should the
input streams (and so the input samples) from different participants be
interleaved to build the output stream? or should they be added in linear
way? are there other alternatives?
Thanks in advance!
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6963
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6963
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7 comments
5 participants
participants (5)
-
Arek Bekiersz -
Atle Samuelsen -
Federico Giannici -
Jorge C -
Nils Ohlmeier