[Serusers] Fw: [Users] TM : retransmission timers

Wed Nov 8 13:16:02 CET 2006

Disclaimer: I am affiliated with SER, iptel.org and allthough attempting 
to give an objective account from a user perspective, I will probably be 
accused of being biased in many of the things I state.
-------------
You may want to read the SER - Getting Started document
http://www.iptel.org/ser/doc/gettingstarted
and especially:
http://siprouter.onsip.org/doc/gettingstarted/ch03.html

Since that was written, OpenSER has released 1.0 and 1.1, while SER is 
now about to release its first major release since the fork.

I haven't followed OpenSER closely, so I cannot speak for it, but SER's 
upcoming release addresses many of the major shortcomings found in 
SER/OpenSER's shared roots, i.e. SER 0.9.x.  These changes include a 
major rewrite of timers, as well as big improvement in the database model.

AFAIK, the module interfaces are still fairly similar, but a major 
difference in how variables and message data is manipulated (thus 
causing modules to be different): openser has further developed the 
pseudo-variables introduced with avpops module, while SER has introduced 
selects.  Which one you prefer is a matter of taste, but IMHO ser.cfg 
for upcoming SER is greatly easier to read, as well as maintain compared 
to the pseudo-variable approach, and it is my firm opinion that new 
users will find SER more intuitive to use when they start getting their 
teeth into SIP server configuration and maintenance.

As for documentation, the SER pre-release does not have complete 
documentation, and yes, the documentation effort is lagging behind a 
bit.  I'm in charge of that effort, and the goal is to have a 
satisfactory set of documentation for the upcoming release.  The last 
few months of improvements at iptel.org are evidence of that process.  
OpenSER has focused on documentation and seems to have a fairly good 
documentation.

Finally, to your wish of combining ser and openser: ser and openser have 
some shared modules, but only where the developers have commited to 
maintaining in both environments.  The cores are by now also quite far 
apart.  So, as each project has its own priorities, expect some features 
to developed in both (by different developers and different code), while 
other features to be only found in one.

In the end, it boils down to which piece of software you feel satisfies 
your needs, whether you have confidence in the project moving in the 
direction you need, and whether the project will deliver the software in 
a satisfactory, bug-free condition at the intervals you need.
g-)

Rao Ramaratnamma wrote:
> sorry for reposting -- I think this question belongs to both mailing list.
> I am really stuck with this.
>
> rr
>
> ----- Forwarded Message ----
> From: Rao Ramaratnamma <raramarat at yahoo.com>
> To: Christian Schlatter <cs at unc.edu>; users at openser.org
> Sent: Tuesday, November 7, 2006 11:15:27 PM
> Subject: Re: [Users] TM : retransmission timers
>
> the ser ottendorf announcement does mention improved timers. Cannot 
> openser include this feature too and cannot I merge ser with openser 
> for good timers? I am still trying to understand the difference 
> between ser and openser but standart compliance seems to be very 
> important matter!
>
> Cannot people provide me with some hints? I am sure that I am not the 
> only who is asking the difference between ser and openser. ser 
> documentation does not appear uptodate, but the software as sannounced 
> appears impressive. I have already asked this question but did not 
> receive any answer.
>
> thank you in advance!
>
> rr
>
> ----- Original Message ----
> From: Christian Schlatter <cs at unc.edu>
> To: users at openser.org
> Sent: Tuesday, November 7, 2006 10:52:56 PM
> Subject: Re: [Users] TM : retransmission timers
>
> Greg Fausak wrote:
> > Hello,
> >
> > I believe this is a well known bug.
> > Granularity of timers is 1 second.  So, if you sign up for a timer to
> > be fired in 1 second it will happen anywhere between 0 seconds and 1
> > second.
> > 2 seconds will happen between 1 and 2 seconds.  I usually set up my
> > timers to be 2, 2, 4, 8.  There are VOIP providers that are pretty
> > sticky about
> > the first 500ms.  If you are using one of them you're out of luck.
>
> Yes, there is a timer process that wakes up every second to perform
> retransmissions. I was actually quite surprised that OpenSER, which is
> known to be very standards compliant, does not follow the RFC 3261
> retransmission timeouts. On the other hand, the RFC 3261 timeout values
> are just suggestions and standards compliant SIP UA must accept shorter
> timeouts. Still it would be nice if OpenSER would support sub second
> timers, this would allow for shorter fail-over times.
>
> Christian
>
> >
> > I believe SER has made timer changes to support more exact timer
> > intervals.  They are a completely different camp, with a different 
> feature
> > set (although they share the same roots).
> >
> > -g
> >
> >
> > On 11/7/06, Jean-François SMIGIELSKI <jf-smig at ibelgique.com> wrote:
> >> Hello,
> >>
> >> I made strange observations about the intervals between
> >> retransmissions with the TM module.
> >> In my experiments,  I used the default parameters for the TM module
> >> timers, and I  sent an INVITE that cannot receive answers (it has a
> >> well  known R-URI pattern that is forwarded to a place and port that
> >> nobody listen).
> >>
> >> When reading RFC3261, I expected to see intervals between
> >> retransmissions of |500ms|1s|2s|4s|8s|16s|. 7 transmissions, during 
> 32s.
> >>
> >> But with OpenSER, (I have tested with the debian package 1.1.0-5 on a
> >> debian etch, and the cvs sources for 1.1.0 or 1.0.1compiled by
> >> myself), I can see intervals like <500ms, 2s, 4s, 4s,4s, ... until 26s
> >> are spent (9 sendings). The first interval is sometomes very short
> >> (40ms).
> >>
> >> Altough I like the sequence of 4s separated transmissions, I do not
> >> know why the first interval is so short, and why there is no sending
> >> after 1s.
> >>
> >> Did anybody observed such behaviours? Are they normal?
> >>
> >> Thanks in advance!
> >>
> >> JF Smigielski.
> >>
> >>
> >> 
> ________________________________________________________________________
> >> iBELGIQUE, exprimez-vous !
> >> http://web.ibelgique.com/
> >>
> >> _______________________________________________
> >> Users mailing list
> >> Users at openser.org
> >> http://openser.org/cgi-bin/mailman/listinfo/users
> >>
> >>
> >>
> >
> >
>
> _______________________________________________
> Users mailing list
> Users at openser.org
> http://openser.org/cgi-bin/mailman/listinfo/users
>
>
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> Serusers mailing list
> Serusers at lists.iptel.org
> http://lists.iptel.org/mailman/listinfo/serusers
>   
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.sip-router.org/pipermail/sr-users/attachments/20061108/b51dad76/attachment.htm>