8 Mar
2005
8 Mar
'05
1:52 a.m.
Hi All.
If I include a session-expires header using append_hf(), do I have to
do anything else to my ser.cfg script?
Also, will this cause re-INVITEs to happen or is there something else needed?
Regards,
Paul
8 Mar
8 Mar
11:20 p.m.
On Tuesday 08 March 2005 00:52, Java Rockx wrote:
If I include a session-expires header using
append_hf(), do I have to
do anything else to my ser.cfg script?
Also, will this cause re-INVITEs to happen or is there something else
needed?
UA's which support Session-Timer?!
Nils
11:54 p.m.
Nils,
Pardon me for asking such simple questions, but is the answer for
generating re-INIVITE messages to simply use SIP clients that support
the header in its configuration?
Regards,
Paul
On Tue, 8 Mar 2005 22:20:06 +0100, Nils Ohlmeier <lists(a)ohlmeier.org> wrote:
On Tuesday 08 March 2005 00:52, Java Rockx wrote:
If I include a session-expires header using
append_hf(), do I have to
do anything else to my ser.cfg script?
Also, will this cause re-INVITEs to happen or is there something else
needed?
UA's which support Session-Timer?!
Nils
9 Mar
9 Mar
12:04 a.m.
On Tuesday 08 March 2005 22:54, Java Rockx wrote:
Pardon me for asking such simple questions, but is the
answer for
generating re-INIVITE messages to simply use SIP clients that support
the header in its configuration?
Both UA's have to support the Session-Timer draft, otherwise the inserted
Session-Expires Header will simply be ignored and you will never see any
re-INVITE's. But if both UA's support the Session-Timer they should normaly
agree on using automatically by looking at the Supported header. So in my
opinion there is no extra value in adding a Session-Expires header to a
request at a proxy.
Nils
Regards,
Paul
On Tue, 8 Mar 2005 22:20:06 +0100, Nils Ohlmeier <lists(a)ohlmeier.org> wrote:
> On Tuesday 08 March 2005 00:52, Java Rockx wrote:
> > If I include a session-expires header using append_hf(), do I have to
> > do anything else to my ser.cfg script?
> >
> > Also, will this cause re-INVITEs to happen or is there something else
> > needed?
>
> UA's which support Session-Timer?!
>
> Nils
1:14 a.m.
Yes, you do need UA supporting this header.
According to section 8 of the draft, draft-ietf-sip-session-timer-14:
Session timers are mostly of interest to call stateful proxy servers
(that is, servers that maintain the state of calls and dialogs
established through them). However, a stateful proxy server (that is,
a server which is aware of transaction state, but does not retain
call or dialog state) MAY also follow the rules described here.
Stateless proxies MUST NOT attempt to request session timers. Proxies
that ask for session timers SHOULD record-route, since they won't
receive refreshes if they don't.
Here, SER is not a call stateful proxy but transaction stateful proxy. It
will not maintain the state of the call. So, even if you insert the header,
it will not change anything from SER's perspective.
However, if as least one of the UA support this header, you may see a BYE
request, which is good for accounting. If neither UA support the header, no
re-INVITE or UPDATE will be generated and that doesn't help you more than
what you have at the moment.
So, until SER becomes call stateful (which is similar to B2BUA, but not the
same), your best hope will be UA that support this header.
Zeus
-----Original Message-----
From: serusers-bounces(a)lists.iptel.org
[mailto:serusers-bounces@lists.iptel.org] On Behalf Of Nils Ohlmeier
Sent: Wednesday, 9 March 2005 9:04 AM
To: Java Rockx
Cc: serusers(a)lists.iptel.org
Subject: Re: [Serusers] Session-Expires Header
On Tuesday 08 March 2005 22:54, Java Rockx wrote:
Pardon me for asking such simple questions, but
is the answer for
generating re-INIVITE messages to simply use SIP clients
that support
the header in its configuration?
Both UA's have to support the Session-Timer draft, otherwise
the inserted
Session-Expires Header will simply be ignored and you will
never see any
re-INVITE's. But if both UA's support the Session-Timer they
should normaly
agree on using automatically by looking at the Supported
header. So in my
opinion there is no extra value in adding a Session-Expires
header to a
request at a proxy.
Nils
Regards,
Paul
On Tue, 8 Mar 2005 22:20:06 +0100, Nils Ohlmeier
<lists(a)ohlmeier.org>
wrote:
> On Tuesday 08 March 2005 00:52, Java Rockx wrote:
> > If I include a session-expires header using
append_hf(), do I have
> > to do anything else to my ser.cfg
script?
> >
> > Also, will this cause re-INVITEs to happen or is there
something
> > else needed?
>
> UA's which support Session-Timer?!
>
> Nils
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3:19 a.m.
At 12:14 AM 3/9/2005, Zeus Ng wrote:
Yes, you do need UA supporting this header.
According to section 8 of the draft, draft-ietf-sip-session-timer-14:
Session timers are mostly of interest to call stateful proxy servers
(that is, servers that maintain the state of calls and dialogs
established through them). However, a stateful proxy server (that is,
a server which is aware of transaction state, but does not retain
call or dialog state) MAY also follow the rules described here.
Stateless proxies MUST NOT attempt to request session timers. Proxies
that ask for session timers SHOULD record-route, since they won't
receive refreshes if they don't.
Here, SER is not a call stateful proxy but transaction stateful proxy. It
will not maintain the state of the call. So, even if you insert the header,
it will not change anything from SER's perspective.
However, if as least one of the UA support this header, you may see a BYE
request, which is good for accounting. If neither UA support the header, no
re-INVITE or UPDATE will be generated and that doesn't help you more than
what you have at the moment.
So, until SER becomes call stateful (which is similar to B2BUA, but not the
same), your best hope will be UA that support this header.
since the case you are raising is accounting accuracy, a pstn gateway is typically
invoivled and it then fair to assume that >=1 UA supports ST. If not, junk the
gateway :)
-jiri
6:50 a.m.
Zeus Ng writes:
So, until SER becomes call stateful (which is similar
to B2BUA, but not the
same), your best hope will be UA that support this header.
how about using uac module for session-timer support in ser?
nils asked abut UAs supporting session timer. i think that cisco gws do
support it.
-- juha
5:09 p.m.
At 05:50 AM 3/9/2005, Juha Heinanen wrote:
Zeus Ng writes:
I don't think you need to do it -- you will be able to introduce it with
basic textual operations. I'm currently having poor connectitivity and
can't easily lookup a good config example but I do have such and will
try to post later.
So, until SER becomes call stateful (which is
similar to B2BUA, but not the
same), your best hope will be UA that support this header.
how about using uac module for session-timer support in ser? nils asked abut UAs supporting session timer. i think
that cisco gws do
support it.
indeed.
-jiri
24 Mar
24 Mar
4:21 a.m.
Jiri,
Did you ever get a chance to post a good config for the session-timer?
Regards,
Paul
On Wed, 09 Mar 2005 16:09:08 +0100, Jiri Kuthan <jiri(a)iptel.org> wrote:
At 05:50 AM 3/9/2005, Juha Heinanen wrote:
Zeus Ng writes:
I don't think you need to do it -- you will be able to introduce it with
basic textual operations. I'm currently having poor connectitivity and
can't easily lookup a good config example but I do have such and will
try to post later.
So, until SER becomes call stateful (which is
similar to B2BUA, but not the
same), your best hope will be UA that support this header.
how about using uac module for session-timer support in ser? nils asked abut UAs supporting session timer. i
think that cisco gws do
support it.
indeed.
-jiri
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serusers(a)lists.iptel.org
http://lists.iptel.org/mailman/listinfo/serusers
9 Mar
9 Mar
3:17 a.m.
At 11:04 PM 3/8/2005, Nils Ohlmeier wrote:
On Tuesday 08 March 2005 22:54, Java Rockx wrote:
That's actually not correct. It is sufficient in one UA supports ST. It is up to
proxy server to handle the case correctly. We do that and there are reasonable
use cases.
-jiri
Pardon me for asking such simple questions, but
is the answer for
generating re-INIVITE messages to simply use SIP clients that support
the header in its configuration?
Both UA's have to support the Session-Timer draft, otherwise the inserted
Session-Expires Header will simply be ignored and you will never see any
re-INVITE's. But if both UA's support the Session-Timer they should normaly
agree on using automatically by looking at the Supported header. So in my
opinion there is no extra value in adding a Session-Expires header to a
request at a proxy. 
9:13 a.m.
Hi!
Jiri Kuthan wrote:
At 11:04 PM 3/8/2005, Nils Ohlmeier wrote:
How does the proxy behave in this case? Are there any things the proxy
has to do to support session timer?
klaus
On Tuesday 08 March 2005 22:54, Java Rockx wrote:
That's actually not correct. It is sufficient in one UA supports ST. It is up to
proxy server to handle the case correctly. We do that and there are reasonable
use cases. Pardon me for asking such simple questions, but is
the answer for
generating re-INIVITE messages to simply use SIP clients that support
the header in its configuration?
Both UA's have to support the Session-Timer draft, otherwise the inserted
Session-Expires Header will simply be ignored and you will never see any
re-INVITE's. But if both UA's support the Session-Timer they should normaly
agree on using automatically by looking at the Supported header. So in my
opinion there is no extra value in adding a Session-Expires header to a
request at a proxy.
12:04 p.m.
On Wednesday 09 March 2005 02:17, Jiri Kuthan wrote:
At 11:04 PM 3/8/2005, Nils Ohlmeier wrote:
I did not wanted to write down this special case, but I feared that someone
will come up with it :-)
But in this special case you will also have to watch out for the replies, if
they contain a Session-Expires header. The draft gives a fairly good overview
what a new SER module would have to do ;-) (although it should also be doable
in the script itself).
Greetings
Nils
Both UA's have to support the Session-Timer
draft, otherwise the inserted
Session-Expires Header will simply be ignored and you will never see any
re-INVITE's. But if both UA's support the Session-Timer they should
normaly agree on using automatically by looking at the Supported header.
So in my opinion there is no extra value in adding a Session-Expires
header to a request at a proxy.
That's actually not correct. It is sufficient in one UA supports ST. It is
up to proxy server to handle the case correctly. We do that and there are
reasonable use cases. 
3:24 p.m.
On 09-03 11:04, Nils Ohlmeier wrote:
On Wednesday 09 March 2005 02:17, Jiri Kuthan wrote:
It can be done in the script, there is no need for a new module, we
have been using it with cisco gateways, they do support session timer,
so the proxy server inserts the headers into requests and replies.
You can test for an INVITE coming from cisco and set an onreply_route.
In the onreply_route you can do something like:
if (status =~ "2[0-9][0-9]") {
remove_hf("Session-Expires");
append_hf("Session-Expires: 120;refresher=UAC\r\n");
};
which "emulates" session-timer support in the user agent that sent 200
OK. After receiving such a reply, the cisco gateway would keep sending
re-INVITEs.
Jan.
At 11:04 PM 3/8/2005, Nils Ohlmeier wrote:
I did not wanted to write down this special case, but I feared that someone
will come up with it :-)
But in this special case you will also have to watch out for the replies, if
they contain a Session-Expires header. The draft gives a fairly good overview
what a new SER module would have to do ;-) (although it should also be doable
in the script itself). Both UA's have to support the Session-Timer
draft, otherwise the inserted
Session-Expires Header will simply be ignored and you will never see any
re-INVITE's. But if both UA's support the Session-Timer they should
normaly agree on using automatically by looking at the Supported header.
So in my opinion there is no extra value in adding a Session-Expires
header to a request at a proxy.
That's actually not correct. It is sufficient in one UA supports ST. It is
up to proxy server to handle the case correctly. We do that and there are
reasonable use cases.
3:59 p.m.
On Wednesday 09 March 2005 14:24, Jan Janak wrote:
On 09-03 11:04, Nils Ohlmeier wrote:
I think in many cases new modules only add more comfortable "high level"
functions, which could also be achieved by writing your own script code.
I did not wanted to write down this special case,
but I feared that
someone will come up with it :-)
But in this special case you will also have to watch out for the replies,
if they contain a Session-Expires header. The draft gives a fairly good
overview what a new SER module would have to do ;-) (although it should
also be doable in the script itself).
It can be done in the script, there is no need for a new module, we
have been using it with cisco gateways, they do support session timer,
so the proxy server inserts the headers into requests and replies. You can test for an INVITE coming from cisco and set
an onreply_route.
In the onreply_route you can do something like:
if (status =~ "2[0-9][0-9]") {
remove_hf("Session-Expires");
append_hf("Session-Expires: 120;refresher=UAC\r\n");
};
But that is actually a vialoation of the Session-Timer draft: the proxy is not
allowed to change (or add) the refresher in the Session-Expires header. Just
adding a Session-Expires header to the reply, if it is not present, should be
sufficient for any implementation which is fully compliant to the latest
Session-Timer draft.
Greetings
Nils
which "emulates" session-timer support in
the user agent that sent 200
OK. After receiving such a reply, the cisco gateway would keep sending
re-INVITEs.
4:21 p.m.
On 09-03 14:59, Nils Ohlmeier wrote:
As I said this is the approach that works with cisco gateways. I have
no idea what is the latest revision of the draft and I do not think it
really matters here, becuase the communication between the proxy and
the gateway is all internal.
This is one particular example that works with cisco, nothing less
nothing more.
Jan.
You can test
for an INVITE coming from cisco and set an onreply_route.
In the onreply_route you can do something like:
if (status =~ "2[0-9][0-9]") {
remove_hf("Session-Expires");
append_hf("Session-Expires: 120;refresher=UAC\r\n");
};
But that is actually a vialoation of the Session-Timer draft: the proxy is not
allowed to change (or add) the refresher in the Session-Expires header. Just
adding a Session-Expires header to the reply, if it is not present, should be
sufficient for any implementation which is fully compliant to the latest
Session-Timer draft. Greetings
Nils
> which "emulates" session-timer support in the user agent that sent 200
> OK. After receiving such a reply, the cisco gateway would keep sending
> re-INVITEs.
6:18 p.m.
At 03:21 PM 3/9/2005, Jan Janak wrote:
On 09-03 14:59, Nils Ohlmeier wrote:
As I said this is the approach that works with cisco gateways.
Other gateway with which it is known to work is Sonus.
-jiri
You can
test for an INVITE coming from cisco and set an onreply_route.
In the onreply_route you can do something like:
if (status =~ "2[0-9][0-9]") {
remove_hf("Session-Expires");
append_hf("Session-Expires: 120;refresher=UAC\r\n");
};
But that is actually a vialoation of the Session-Timer draft: the proxy is not
allowed to change (or add) the refresher in the Session-Expires header. Just
adding a Session-Expires header to the reply, if it is not present, should be
sufficient for any implementation which is fully compliant to the latest
Session-Timer draft.
5:13 p.m.
At 11:04 AM 3/9/2005, Nils Ohlmeier wrote:
On Wednesday 09 March 2005 02:17, Jiri Kuthan wrote:
As a matter of fact, it is actually the regular case whcih we deployed in
production networks. It was just a script thing. I'm currently having
difficulties accessing my home server to send out some examples but there
are such.
-jiri
At 11:04 PM 3/8/2005, Nils Ohlmeier wrote:
I did not wanted to write down this special case, but I feared that someone
will come up with it :-) Both UA's have to support the Session-Timer
draft, otherwise the inserted
Session-Expires Header will simply be ignored and you will never see any
re-INVITE's. But if both UA's support the Session-Timer they should
normaly agree on using automatically by looking at the Supported header.
So in my opinion there is no extra value in adding a Session-Expires
header to a request at a proxy.
That's actually not correct. It is sufficient in one UA supports ST. It is
up to proxy server to handle the case correctly. We do that and there are
reasonable use cases.
7214
days inactive
7231
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17 comments
7 participants
participants (7)
-
Jan Janak -
Java Rockx -
Jiri Kuthan -
Juha Heinanen -
Klaus Darilion -
Nils Ohlmeier -
Zeus Ng