Date: Wed, 3 Jun 1998 10:07:43 +0200 (METDST) From: hm@hcs.de (Hellmuth Michaelis) To: freebsd-isdn@FreeBSD.ORG (ISDN Mailinglist) Subject: Re: Not quite an error message in layer3/i4b_q931.c Message-ID: <m0yh8aF-00006jC@hcswork.hcs.de> In-Reply-To: <Pine.BSF.3.96.980602204037.7462A-100000@transit.hanse.de> from Stefan Bethke at "Jun 2, 98 10:38:10 pm"
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>From the keyboard of Stefan Bethke: > In layer3/i4b_q931.c, around line 358, an incoming SETUP message is > checked. If no or an invalid channel_id is presented, an error message is > logged. > > This might seem quite right, but it isn't. An incoming SETUP without a > channel indication (Q.931, 4.5.13, octet 3, bits 2-1=00=no channel), > means, as per 5.2.3.2 b), that no B channel is available, This might be true. I'd like to support "CW" but my copy of Q.953 does not have Clause 1, where CW is described. > Alternatively, if the user doesn't > implement call waiting, it must respond with RELEASE COMPLETE, cause 34, > no channel available. Not quite true. It _may_ respond with RELEASE COMPLETE but it _must_ not. Q.931 03/93, p 133/134 says that in case 4) the user shall reject the call by sending RELEASE COMPLETE, cause 34, but paragraph 5.2.2 on page 134 also says, that an incompatible destination may ignore an incoming SETUP. I4b is currently incompatible with this case, so it ignores this SETUP. Anyway, responding with RELEASE COMPLETE may be the better way, but before i implement this, i'd like to know what the CW standard doc says. If anyone has a description of CW, i'd like to read it. (Perhaps someone has a slightly outdated ITU CD and likes to contribute it instead of throwing it away :-) hellmuth -- Hellmuth Michaelis Tel +49 40 559747-70 HCS Hanseatischer Computerservice GmbH Fax +49 40 559747-77 Oldesloer Strasse 97-99 Mail hm@hcs.de 22457 Hamburg WWW http://www.hcs.de To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isdn" in the body of the message
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