Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!uwmcsd1!marque!uunet!pdn!larry
From: larry@pdn.UUCP (Larry Swift)
Newsgroups: comp.protocols.iso
Subject: Re: ISDN, Layer 3
Message-ID: <4183@pdn.UUCP>
Date: 26 Aug 88 14:32:00 GMT
References: <4091@pdn.UUCP> <3080@druco.ATT.COM>
Reply-To: larry@pdn.UUCP (0000-Larry Swift)
Organization: Paradyne Corporation, Largo, Florida
Lines: 47

Don, thanks for the info.  Some additional questions:

In article <3080@druco.ATT.COM> stanwyck@druco.ATT.COM (D. Stanwyck) writes:
>User-user signalling is a service where the two "users" (hint- user <>
>end-system) may send information between themselves in the call control
>messages.  This comes is several varieties - some associated with a
>circuit-switched call, and at least one not associated with any other
>communication path.  This latter is the type you mention above.
>
>For this connection type, the network is told that all you want is to relay
>messages between the users without establishing a related communication
>path for e.g., a voice call.  You could (correctly) call this using the
>CCS7 network or whatever the network's internal common channel signalling
>fabric is based on as a packet-switching network.  As a result, not all
>network providers are jumping eagerly into this service, as the user data
>flows could potentially (and likely) block call-related signalling
>information.

This discription almost sounds synonymous with OSI's "connectionless"
service, which isn't flow-controlled.  Is that a reasonable association?

>....  The brief answer is that Disconnect Request does not require the
>termination of all communication - i.e., you could potentially keep some
>type of user-user signalling up, while release request occurs some messages
>later and implies a total release of communications.

Can you give some idea of application?

>Overlap sending/receiving and overlap modes relate to whether the address
>information is all carried in one message or is sent piecemeal to/from the
>exchange.  Both are possibilities.

Just curious here.  Do you have an idea as to how the term "overlap" came
to be used?

>You really should get a copy of the current draft proposed American National
>Standard (DpANS) based on Q.931.  It should be out for ballot by the end of
>this year.

I have Q.931; is the ANSI draft substantially different?  more readable?
I'll try to get a copy.


Larry Swift                     UUCP: {peora,uunet}!pdn!larry
Paradyne Corp., LF-207          Phone: (813) 530-8605
P. O. Box 2826
Largo, FL, 34649-9981           She's old and she's creaky, but she holds!