Sip Dect Capacity Limitations - Nortel CS 1000 User Manual

Primary DN. The additional DN configured in CallPilot is the external DN of
DECT handset, that is, the Target DN on the UEXT corresponding to the
DECT handset.
Communication Server 1000 only supports the so-called Unsolicited MWI
NOTIFY model
An external SIP UA cannot SUBSCRIBE to MWI NOTIFY messages and
cannot request the current status of MWI for the DN from the system
(by sending SUBSCRIBE messages). Instead of that a SIP UA has
to be ready to get MWI NOTIFY messages from system even if it did
not SUBSCRIBE to those and it has to update MWI according to those
messages only.
Due to the Unsolicited MWI NOTIFY model in Release 5.5, the DECT
handset can only rely on the MWI notifications sent by Communication
Server 1000. Therefore, the MWI indication based on that existing
mechanism may not be in the correct state on the DECT handset if the
handset was turned off and then turned on. Also, the MWI indication
may not be in the correct state if the user of the handset goes out of the
coverage area of the SIP DECT system and then enters the coverage area
again. In such a situation, the MWI indication on the DECT handset is
guaranteed to be in the correct state only after the next MWI state change
happens in the CallPilot system.
If a twinned configuration is used for a DECT handset, the corresponding
IP or TDM phone always correctly reflects the current state of MWI,
assuming that it receives MWI notifications for its Primary DN from
CallPilot.

SIP DECT capacity limitations

The following capacity limitations apply to SIP DECT.
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Consider the following additional capacity limitations based on the
Communication Server 1000 configuration characteristics.
Copyright © 2008-2009 Nortel Networks
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a maximum of 12 simultaneous calls for each DAP
a maximum of 256 DAPs on each network (where hand over and
synchronization between DAPs is possible)
a maximum of 6000 DECT handsets on each SIP DECT system (there
can potentially be several isolated SIP DECT systems connected to
Communication Server 1000)
a maximum of 1000 simultaneous calls on each network
a maximum of 25 subscription records for each DAP
If the planned number of DECT handsets in a SIP DECT system is
equal to M, and the number of DAPs in that system is equal to N, M
must be less than or equal to N*25.
Nortel Communication Server 1000
SIP DECT Fundamentals
NN43120-123 01.07
6 January 2009
Overview of SIP DECT 17