asterisk users - Feb 2004 - SIP extension "busy" when not available ??

How come * says 1010 is BUSY in the trace below? I would have guessed
"UNAVAILABLE" since 1010 is not logged on/registered.

*****
[root@asterisk asterisk]# asterisk -vvvvvvvvfcg
...
Asterisk CVS-02/21/04-15:10:20, Copyright (C) 1999-2001 Linux Support
Services, Inc.
...
...
    -- Executing Macro("SIP/1000-2806",
"stdexten|1010|SIP/1010") in new
stack
    -- Executing Dial("SIP/1000-2806", "SIP/1010|20|tr") in
new stack
Feb 22 02:21:19 NOTICE[278545]: app_dial.c:527 dial_exec: Unable to create
channel of type 'SIP'
  == Everyone is busy at this time
    -- Executing VoiceMail("SIP/1000-2806", "b1010") in new
stack
...
...
sip show peers
Name/username    Host                 Mask             Port     Status
2000             (Unspecified)   (D)  255.255.255.255  0        UNKNOWN
1020             (Unspecified)   (D)  255.255.255.255  0        UNKNOWN
1010             (Unspecified)   (D)  255.255.255.255  0        UNKNOWN
1000/1000        192.168.0.65    (D)  255.255.255.255  5061     OK (9 ms)

[macro-stdexten];
exten => s,1,Dial(${ARG2},20,tr)                ; Ring the interface, 20
seconds maximum
exten => s,2,Voicemail(u${ARG1})                ; If unavailable, send to
voicemail w/ unavail announce
exten => s,3,Goto(default,s,1)                  ; If they press #, return to
start
exten => s,102,Voicemail(b${ARG1})              ; If busy, send to voicemail
w/ busy announce
exten => s,103,Goto(default,s,1)                ; If they press #, return to
start

*****

/Soren
-- 
"It is the mark of an educated mind to be able to entertain a thought
without accepting it."
- Aristotle

> How come * says 1010 is BUSY in the trace below? I would have guessed
> "UNAVAILABLE" since 1010 is not logged on/registered.
That's what has been programmed in the asterisk code and has been that way
since the beginning of time. I don't like it either, but I'm not a
programmer
and can't change it.

The logical response really should be Unavailable, but apparently there must
be a reason why no one has changed this. It would appear part of the reason
behind this is that asterisk stores the last known status of each sip
phone's
Register in a database entry (which is what gets displayed in the "sip show
registry" command), and should the logical connection to that SIP phone be 
lost 10 seconds after the register, asterisk would not know that.

Although the current logic does not require a sip phone to register, it would
seem like the asterisk logic should be something like:
 a. call is attempted to sip x1234,
 b. if * knows the extn is in use, return busy, or,
 c. if not busy, asterisk attempts to contact x1234 across the wire,
 d. if no contact, return Unavailable
The sip phone could be busy since it could actually have another call in
progress
with some other sip proxy other then asterisk, so I'm sure there is far more
logic required then what meets this non-programmers eye.

Rich

Soren Rathje said:
> ----- Original Message -----
> From: "Olle E. Johansson" <oej@edvina.net>
> To: <asterisk-users@lists.digium.com>
> Sent: Sunday, February 22, 2004 8:52 PM
> Subject: Re: [Asterisk-Users] SIP extension "busy" when not
available ??
>
>
>> > Although the current logic does not require a sip phone to
register,
>> it
> would
>> > seem like the asterisk logic should be something like:
>> >  a. call is attempted to sip x1234,
>> >  b. if * knows the extn is in use, return busy, or,
>> >  c. if not busy, asterisk attempts to contact x1234 across the
wire,
>> >  d. if no contact, return Unavailable
>> Or if not registred.
>>
>
> In a wireline telephony scenario the above would be the proper method as
> we
> do not know if the subscriber have their phone plugged in or not. With
> Asterisk we experience the same information as mobile operators do:
> "unreachable", "unanswered" and "busy". IMHO
we should have the same
> options.
>
> So, the priority for a type=friend would be:
> a: check if client is registered and/or reachable, if not - return
> "unreachable"
> b: check if client is busy, if call-waiting not active - return
"busy"
> c: if call is rejected by client, return approriate message
> d: if call is unanswered, return "unavailable" or
"busy" with reference to
> (b).
>
> -- Soren
I use  ChanIsAvail()  to check to see if the phone is connected at the top
of the dialplan for that extension. This works for IAX2 and SIP channels
but not for MGCP.

If you are interested in the actual code I can send it to you from home
tonight.

Robert