ETSI TISPAN

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• ETSI TISPAN
• call completion services
• (draft-poetzl-sipping-call-completion-00)
• Roland Jesske r.jesske_at_t-com.net
• Martin Huelsemann martin.huelsemann_at_t-com.net

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• E T S I
• European Telecommunications Standards Institute
• http//portal.etsi.org
• T I S P A N
• NGN standardisation group in ETSI
• http//portal.etsi.org/tispan/TISPAN_ToR.asp

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• Services in scope
• Communication Completion on Busy Subscriber
  (CCBS)
• Communication Completion on no Reply (CCNR)

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• I-Ds related
• draft-jesske-sipping-tispan-requirements-03
• draft-poetzl-sipping-call-completion-00

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Call completion service on queue basis-
uncoordinated call completion services might lead
to the situation where the first user activating
call completion might be the last user whos call
is completed - a sequential organised (FIFO)
call completion service on a busy user can be
realised by a network element capable to queue
call completion requests- the first user who
requests call completion is the first user who is
informed that a call completion call is possible
now- call completion calls have a higher
priority than normal calls
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General framework- solutions should be based
on existing SIP means (BCP)- solutions should
be simple- solutions must be interoperable with
existing PSTN call completion services
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Open issues for call completion services-
Indication that a subscription to a call
completion queue is possible - Capability of
management of call completion queues-
Prioritisation of call completion calls
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Issue 1Indication that a UA or application
server on the terminating side is able to add
requests from the originating side to a call
completion queue.Proposed solutionUsage of
the Allow-Events header in 486 Busy responses for
CCBS and in 180 Ringing responses for CCNR.
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Issue 2 Management of call completion queues
between network elements. The queuing capability
can be implemented in UAs as well as in
application servers. After being added a user
shall be able to suspend, resume or cancel his
position in the call completion queue. Existing
SIP means do not fulfil this requirement, e.g.
the dialog event package informs about status of
a dialog, needed is information about the status
of a queue (dialog terminated unequal ready
for recall)Proposed solutionUsage of
SUBSCRIBE/NOTIFY to subscribe to and manage a
call completion queue and to receive
notifications of changes in the status of the
queue.Specification of two new event packages
(CCBS and CCNR).
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Issue 3 Prioritisation of call completion
calls.Call completion calls must be
distinguishable from new incoming calls in order
to avoid queuing or blocking at the terminating
side.Proposed solutionDefinition of a
private header which can transport a specific
call completion indication P-Service-Indication
header
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To do adding of explanatory text and
signalling flows.Needed reviewing, comments
and discussion.
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Backup
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Call completion event packageDefines several
event header parameters, amongst others-
queue-operation (add, suspend, resume)-
queue-state (request-queued, user-free-for-recall)
- cancellation-reason (service-duration max.
time for service activation expired,
CCSS-completed)- denial-reason
(short-term-denial e.g. max. number of requests
queued, long-term-denial)- caller uniquely
identifies the user who has originated the call
completion subscription
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P-Service-Indication header- may be used by
network elements in certain deployment scenarios
to request a special processing of their SIP
requests or responses- a UAC may include one or
more P-Service-Indication header fields in a
request- a UAS receiving a request including a
P-Service-Indication header field may inspect it
in order to apply service-specific features a
UAS may include one or more P-Service-Indication
header fields in a response - a proxy receiving
a request including a P-Service-Indication header
filed may inspect it in order to process the
message accordingly a proxy may add or remove
P-Service-Indication header fields