🚀 go-pugleaf

in article <4091@pdn.UUCP>, larry@pdn.UUCP (Larry Swift) says:
> 1) I'm having difficulty understanding the term "user-to-user signalling"
> which seems to be used in opposition to circuit-switching and packet
> switching.  These three service type seem to make up the Layer 3 offering,
> but the difference between the first two escapes me.
 
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.

> 2) Where and how is leased circuit support accomplished?  I see an
> occasional reference to it, but no clear descriptions.
 
Leased circuits are not dealt with in the Recommendations.  At this time
(though not necessarily in the future) they are strictly administrative
items between you and the networks involved.  No signalling related to
them is defined.

> 3) What is the difference between "Release Request" and "Disconnect
> Request" in the call control states described in Section 2 of Q.931?
 
This is a specific technical point - probably better dealt with by mail or
phone.  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.

> 4) What is "Suspend" used for (same section)?

Nothing in the US.  Suspend/Resume is used in some (one) European network
for an desired ability for you to take your ISDN set, tell the other party
to hang on, unplug your phone, walk down the street a few houses, plug it
in there, and resume the conversation that was in progress at the other
location.  Of course, if you happen to walk across the boundary between
exchanges, or take longer than <network defined timer>, the call will
collapse and you won't be able to resume.

> 5) What are the terms "overlap sending/receiving" and "overlap mode" 
> descriptive of (same section)?

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.

> Larry Swift                     UUCP: {peora,uunet}!pdn!larry
> Paradyne Corp., LF-207          Phone: (813) 530-8605

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.  Otherwise, join T1S1 and attend T1S1.2 or see your company
representative who does attend (Paradyne's mailing list member is Wayne
Moore at MS LF104, 813-530-8262). 
-- 
AT&T 				o  o			303-538-5004
Don Stanwyck		         ||   			druco!stanwyck
Denver, CO USA			\__/			Telecom Standards