ATT Definity Addendum 1 For Ds1, Dmi, Isdn Pri Instructions Manual

INTRODUCTION1-29
The ISDN-PRI level-3 messages are a collection of IEs that are defined in the Q.931 recommendations.
Each message has at least one IE. IEs are transmitted and received over the D-channel. IEs contain
three headers: protocol discriminator, call reference, and message type. Figure 1-9, ISDN Message
Signaling Format, shows the message-signaling format.½
FIRST OCTET
PROTOCOL DISCRIMINATOR
CALL REFERENCE
MESSAGE TYPE
INFORMATION ELEMENTS
(OPTIONAL)
INFORMATION ELEMENTS
LAST OCTET
Figure 1-9....

1-30INTRODUCTION
Except for DCS, the originating and terminating switches do channel negotiation to select a channel that
is compatible with both endpoints. Channel negotiation gives some control of the B-channel used for a
call. If the originating endpoint chooses a B-channel that is unacceptable to the terminating endpoint
(for example, planned use of the channel by the terminating endpoint), then the terminating endpoint can
request a change in the channel to be used for that call.
Although Q.931...

INTRODUCTION1-31
lMore efficient and effective use of ISDN-PRI network access trunks
lMore access trunks available for call routing (providing an improvement in the grade of service)
lReduction (usually) in the number of access trunks needed to provide the required grade of service,
because of the increase in efficiency
CBC Service Selection is a public network ISDN feature. The AT&T ISDN network provides CBC
Service Selection for AT&T ISDN nodal services (such as MEGACOM service, MEGACOM 800
service,...

1-32INTRODUCTION
Generic 1 — CBC Implementation½
The following describes details of CBC on Generic 1:
1.
2.
3.The SID-ANI number can be received either per trunk group or per call
When receiving calls over a CBC trunk group, define the usage-allocation plans. These plans
prevent a particular nodal service from monopolizing a trunk group or being deprived of the
minimum number of trunks.
On Generic 1, the “service type” field on the trunk group form permits entries such as CBC,
access, tie, and tandem....

INTRODUCTION1-33
Interworking between ISDN-PRI and DCS is a complex issue that is beyond the scope of this
document. However, for pure ISDN-PRI or combined ISDN-PRI/DCS networks, several new
ISDN feature and service options are available. These include: 5.½
l
l
l
l
l
l
l
lCall routing based on BC
End-to-end ISDN connectivity routing
BC passed on a call-by-call basis
User-to-user information transport
Locally provided tones
Controlled initialization of trunks to in-service at provisioning time
Two-way...

1-34INTRODUCTION
Full DCS feature transparency is provided between two or more Generic 2s interconnected with
ISDN-PRI facilities. The supported voice terminal features include:
lAbbreviated dialing
lAlphanumeric display (DCS)½
½
lAutomatic callback
lCall coverage
lCall forwarding — all calls
lCall waiting — terminating
lCall waiting — conference
lPriority calls
lDistinctive ringing
lLeave word — calling (no AP)
lLeave word — call transfer
8.When ISDN-PRI facilities connect an ETN main to an ETN tandem,...

2. NETWORK CONNECTIONS AND CONFIGURATIONS
This chapter provides a description of common connection arrangements with System 85 R2V4,
DEFINITY® Communications System Generic 1 and Generic 2. These connections include private
network, public network, and those made through digital signal level 1 (DS1) auxiliary equipment. Also
included is a description of the services provided by each connection, any option restrictions, and
relevant synchronization issues.½
The equipment used for completing the end-to-end...

2-2NETWORK CONNECTIONS AND CONFIGURATIONS
5.
6.
7.Counting the number of messages and comparing this to other trunks
Determining whether a channel is hyperactive
Maintenance busying out a virtual trunk group with hyperactive channels or returning cleared
channels to normal service
For more information about troubleshooting hyperactivity, refer to DEFINITY Communications
System Generic 2 Maintenance Repair Strategies (555-104-118).½
Normal, though temporarily high, levels of ISDN-PRI D-channel signaling...

NETWORK CONNECTIONS AND CONFIGURATIONS2-11
The assignment of CEM channels must be coordinated with the DS1/DMI-BOS channel assignments on
the switch. This is necessary so that only voice and voice-grade data channels are compressed and so
that digital data or 24th-signaling channels pass through uncompressed.
The CEM does not place any restriction on a DS1/DMI-BOS between the switch and the CEM.
Therefore, this interface may use either D4 or ESF framing, 24th-channel or robbed-bit signaling, and
either...

2-12NETWORK CONNECTIONS AND CONFIGURATIONS
5.
6.It is the only signaling type that permits uncompressed channels, from both DS1/DMI-BOSes, to
be connected to the CEM. Bundling is required when both DS1/DMI-BOSes operate with 24th-
channel signaling.
It is required when the CEM is used with a CDM
The third signaling format is called DMI-46. This format uses DMI-BOS over the 24th channel of the
compressed facility, leaving 46 compressed channels available for voice. DMI-46 is usually selected
only when the...