Subject: [Sip] problem with sip resonse code mapping to isup

From: Juha Heinanen <[email-masked]>
Date: Tue, 22 Jan 2002 16:33:40 +0200

if i try to call from pstn to a sip phone that is not currently
registered, the home proxy of the phone returns "404 not found".
according to draft-ietf-sipping-isup-00.txt the sip/isup gw then maps
that to "1 Unallocated number".

i think this is plain wrong, because surely the number has been
allocated to the sip phone.  the phone just happens to be off-line.  in
finland pstn turns "1 Unallocated number" into a voice reply that goes
something like "the number doesn't exist, please check the number and
try again".  from that the called gets the wrong impression that he has
got a wrong number.

if i call to a cell phone that happens to be offline, i get from pstn a
message that goes something like "the number you tried to call is not
currently reachable, please try again later".  i believe this is
generated from "18 No user responding".

i would like to get this same announcement if i call a sip phone whose
number is not currently registered, but which the proxy knows exists in
its domain.  according to the table in draft-ietf-sipping-isup-00.txt, i
can get "18 No user responding" if the proxy would return "480
Temporarily unavailable". this however, is not possible according to
bis-05:

23.4.16 480 Temporarily Unavailable The callees end system was
contacted successfully but the callee is currently unavailable
(e.g., not logged in, logged in in such a manner as to
preclude communication with the callee or activated the do not
disturb feature).

i.e., only the phone, not the proxy, can return such a message, but
obviously in this case it can't because proxy doesn't know where the
phone is and thus can't forward the invite to it.

clearly something needs to be done in order to resolve this issue.  i'll
include also the sip list, since it would be possible to do the fix in
either document.  my initial feeling is that we would need a new error
response "4xx Offline", alternatively we need to change the wording of
404, because now 404 should be returned if the "user doesn't exist",
which to very ambiguous to me.

-- juha

_______________________________________________
Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [email-masked] for questions on current sip
Use [email-masked] for new developments on the application of sip

---

From: Christer Holmberg <[email-masked]>
Date: Wed, 23 Jan 2002 20:19:34 +0200

Hi Juha,

I think this question is a little related to one I had about the loose
route proposal.

My question then was: what does a proxy return if it receives an INVITE
request with a pre-loaded route, and for whatever reason it is not able,
or is not allowed to forward the request to that proxy. For most cases
there are response codes available. But, if the following server is
temporary "out of reach" I am not sure there were an exact code to use,
but I think 403 was "as close as possible".

Regards,

Christer Holmberg
Ericsson Finland

---

From: Juha Heinanen <[email-masked]>
Date: Wed, 23 Jan 2002 20:38:53 +0200

may be "404 not found" is ok for the case when the called user is
"offline", but definitely it is not ok to map that to "1 unallocated
number".  as i said, the sip spec could be a bit clearer on what the
semantics of "not found" are.

if "404 not found" is to be used also in the case when the proxy knows
that the called user exists, but currently has no active registration,
then correct isup mapping would be "18 no user responding".  the only
sip result code that i think could be mapped to "1 unallocated
number" is "604 does not exist anywhere", which is not even mentioned in
the table of draft-ietf-sipping-isup-00.txt.

i'm wondering what has happened to the authors of
draft-ietf-sipping-isup-00.txt, since noone has showed up to defend
their table.  may be they are "410 gone" :-).

-- juha

---

From: Gonzalo Camarillo <[email-masked]>
Date: Wed, 23 Jan 2002 23:03:02 +0200

Hello Juha,

> their table.  may be they are "410 gone" :-).

We are pretty busy finishing bis-06. That's why we had not answered your
mail before. Anyway, if you send the mail to the mailing list and cc us
as well you will get faster responses.

The definition of 480 Temporarily unvailable says: "This status is also
returned by a redirect server that recognizes the user identified by the
Request-URI but does not currently have a valid forwarding location for
that user."

We will change "redirect server" by "redirect or proxy server" in
bis-06. 

With this change, your example does not work because your SIP server is
returning 404 instead of 480. If it returns 480 the tables in the
mapping draft work fine.

Thanks,

Gonzalo

Juha Heinanen wrote:
> Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
> This list is for NEW development of the application of SIP
> Use [email-masked] for new developments of core SIP

-- 
Gonzalo Camarillo                    Phone :   +1 212 939 71 71
Columbia University                  Mobile:  +358 40 702 35 35
472 Computer Science Building        Fax   :  +358  9 299 30 52
1214 Amsterdam Ave., Mail Code 0401  http://www.hut.fi/~gonzalo
New York, NY 10027                   
USA                              [email-masked]