Lucent Technologies DEFINITY Enterprise Communication Server Release 8.2 Administrators Guide

							DEFINITY ECS Release 8.2
Administrator’s Guide  555-233-506  Issue 1
April 2000
Features and technical reference 
1587 Wideband Switching 
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Wideband Switching
(Not available with Offer B) Wideband Switching provides the ability to dedicate 
2 or more ISDN-PRI B-channels or DS0 endpoints for applications that require 
large bandwidth. It provides high-speed end-to-end connectivity between 
endpoints where dedicated facilities are not economic or appropriate. ISDN-BRI 
trunks do not support wideband switching.
Brief description
ISDN-PRI (and the emulation of it by Asynchronous Transfer Mode-Circuit 
Emulation Service (ATM-CES)) divides a T1 or E1 trunk into 24 (31 for E1) 
information channels and one signaling channel for standard narrowband 
communication. Certain applications, like video conferencing, require greater 
bandwidth. You can combine several narrowband channels into one wideband 
channel to accommodate the extra bandwidth requirement. DEFINITY ECS 
serves as a gateway to many types of high-bandwidth traffic. Wideband switching 
is also supported by the Expansion Interface (EI) circuit pack and the DS1 
Converter circuit pack (for Center Stage Switching or directly connected port 
networks) and the ATM-EI circuit pack (for Asynchronous Transfer Mode 
connected port networks). ATM-CES supports wideband switching only for 
access, tie, and tandem trunks, not for line-side connections.
Wideband Switching supports:
nHigh-speed video conferencing
nWAN disaster recovery
nScheduled batch processing (for example, nightly file transfers)
nLAN interconnections and imaging
nOther high bandwidth applications involving high-speed data transmission, 
video transmission, etc. 
How to administer Wideband Switching
The following list shows the required screens you must to set up Wideband 
Switching:
nAccess Endpoint
nPRI Endpoint
nISDN trunk group
nRoute Pattern
nFiber Link Administration (Optional: refer to the DEFINTY services 
documentation for information about this screen.) 
						

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Administrator’s Guide  555-233-506  Issue 1
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Channel allocation
For standard narrowband communication, ISDN-PRI divides a T1 or E1 trunk as 
follows:
nT1 trunks are divided into 23 information channels and 1 signaling channel
nE1 trunks are divided into 30 information channels, 1 signaling channel, 
and 1 framing channel
Certain applications, like video conferencing, require greater bandwidth. You can 
combine several narrowband channels into one wideband channel to 
accommodate the extra bandwidth requirement. DEFINITY ECS serves as a 
gateway to many types of high-bandwidth traffic. In addition, DS1 converters are 
used for wideband switching at remote locations.
The following table provides information on Wideband Switching channel types.
Perform wideband line-side
 channel allocation using one of three allocation 
algorithms: fixed, flexible, or floating.
nFixed allocation — Provides contiguous-channel aggregation. The starting 
channel is constrained to a predetermined starting point. (Used only for H0, 
H11, and H12 calls.)
nFlexible allocation — Allows a wideband call to occupy noncontiguous 
positions within a single T1 or E1 facility.
nFloating allocation — Enforces contiguous-channel aggregation. The 
starting channel is not constrained to a predetermined starting point.
Channel Type Number of Channels Data Rate
H0 6 384 Kbps
H11 24 1536 Kbps
H12 30 1920 Kbps
NXDS0 (T1) 2-24 128–1536 Kbps
NXDS0 (E1) 2-31 128–1984 Kbps 
						

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Administrator’s Guide  555-233-506  Issue 1
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Typical uses
A typical video application uses an ISDN-PRI interface to DS0 1 through 6 of the 
line-side facility. Refer to the following figure.
Figure Notes
Endpoint applications with signaling
An endpoint application is the origination or destination point of a wideband call. 
Endpoint applications can be any number of data applications based on the 
customer’s particular needs.
ISDN-PRI terminal adapters
For wideband switching with non-ISDN-PRI equipment, you can use an 
ISDN-PRI terminal adapter. ISDN-PRI terminal adapters translate standard ISDN 
signaling into a form that can be used by the endpoint application and vice versa. 1. Video application
2. Port 1
3. Port 2
4. ISDN terminal adaptor
5. Line-side ISDN-PRI
6. DEFINITY ECS
7. ISDN or ATM-CES trunk8. Network
9. DS0 24 D-channel
10. DS0 23 unused
11. DS0 1–6 wideband
12. DS0 24 D-channel
13. DS0 7–23 narrow bands
14. DS0 1–6 wideband
wdbndex CJL 061996 
						

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The terminal adapter also must adhere to the PRI-endpoint boundaries as 
administered on the DEFINITY ECS switch when handling both incoming (to the 
endpoint) applications and outgoing calls.
The terminal adapter passes calls to and receives calls from the line-side 
ISDN-SETUP messages indicating the data rate and specific B-channels (DS0) to 
be used and communicates all other call status information via standard ISDN 
messages. Refer to DEFINITY Line-Side ISDN Primary Rate Interface Technical 
Reference for more information.
Line-side (T1 or E1) ISDN-PRI facility
A line-side ISDN-PRI (T1 or E1) facility is comprised of a group of DS0s (24 for 
a T1 facility and 32 for an E1 facility). In this context, these DS0s are also called 
channels. T1 facilities have 23 B-channels and a single D-channel. E1 facilities 
have 30 B-channels, 1 D-channel, and a framing channel. Data flows 
bi-directionally across the facility between the switch and the ISDN-PRI terminal 
adapter.
PRI-endpoints
A PRI-endpoint (PE) is a combination of DS0 B-channels on a line-side 
ISDN-PRI facility that has been assigned an extension.
A PRI-endpoint can support calls of lower bandwidth. In other words, a PE having 
a width 6 (six DS0s) can handle a call of one channel (64 Kbps) up to and 
including six channels (384 Kbps). Also, a PE can support calls on non-adjacent 
channels. For example, an endpoint application connected to a PE defined as using 
B-channels 1 through 6 of an ISDN-PRI facility could originate a call using 
B-channels 1, 3, and 5 successfully. If the PE has been administered to use flexible 
channel allocation, the algorithm for offering a call to the PE starts from the first 
DS0 administered to the PE. Since only one active call is permitted on a PE, 
contiguous B-channels are always selected unless one or more B-channels are not 
in service.
A PE remains in service unless all of its B-channels are out of service. In other 
words, if B-channel 1 is out of service and the PE is five B-channels wide, the PE 
could still handle a wideband call of up to four B-channels in width. A PE can 
only be active on a single call at any given time; that is, it is either considered idle, 
active (busy), or out of service.
One facility can support multiple separate and distinct PRI-endpoints (several 
extensions) within a single facility. Non-overlapping contiguous sets of DS0s 
(B-channels) are associated with each PE. 
						

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Universal digital signal level 1 board
The UDS1 board is the interface for line-side and network facilities carrying 
wideband calls.
Non-signaling endpoint applications
Wideband can also support configurations using non-signaling (non-ISDN-PRI) 
line-side T1 or E1 facilities. The endpoint applications are the same as those 
defined for configurations with signaling.
Data service unit/channel service unit
This unit simply passes the call to the endpoint application. Unlike terminal 
adapters, the DSU/CSU does not have signaling capability.
NOTE:
No DSU/CSU is needed if the endpoint application has a fractional T1 
interface.
Line-side (T1 or E1) facility
This facility, like the ISDN-PRI facility, is composed of a group of DS0s (23 for a 
T1 facility and 30 for an E1 facility). Line-side facilities are controlled solely from 
the switch. Through the access-endpoint command, a specific DS0 or group of 
DS0s is assigned an extension. This individual DS0 or group, along with the 
extension, is known as a wideband access endpoint (WAE).
Wideband access endpoint
WAEs have no signaling interface to the switch. These endpoints simply transmit 
and receive wideband data when the connection is active.
NOTE:
The switch can determine if the connection is active, but this does not 
necessarily mean that data is actually coming across the connection.
A WAE is treated as a single endpoint and can support only one call. If all DS0s 
comprising a wideband access endpoint are in service, then the wideband access 
endpoint is considered in service. Otherwise, the wideband access endpoint is 
considered out of service. If an in-service wideband access endpoint has no active 
calls on its DS0s, it is considered idle. Otherwise, the wideband access endpoint is 
considered busy.
Multiple WAEs are separate and distinct within the facility and endpoint 
applications must be administered to send and receive the correct data rate over 
the correct DS0s. An incoming call at the incorrect data rate is blocked. 
						

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Guidelines and examples
This section examines wideband and its components in relation to the following 
specific customer usage scenarios:
nHigh-speed video conferencing 
nData backup connection
nScheduled batch processing
nPrimary data connectivity
nNetworking
High-speed video conferencing
All data rates are multiples of 64 Kbps; from 128 Kbps to 1,536 Kbps (T1) and 
1,984 Kbps (E1) are supported. Key customer data rates are listed below.
Data backup connection
Using wideband for data transmission backup provides customers with alternate 
transmission paths for critical data in the event of primary transmission path 
failure.
Scheduled batch processing. Scheduled batch processing applications are used 
for periodic database updates (for example, retail inventory) or distributions (for 
example, airline fare schedules). These updates are primarily done after business 
hours and are often referred to as nightly file transfers. Wideband meets the high 
bandwidth requirements at low cost for scheduled batch processing. In addition, 
wideband allows the dedicated-access bandwidth for busy-hour switch traffic to 
be used for these applications after business hours; no additional bandwidth costs 
are incurred.
The non-ISDN backup data connection is also appropriate for scheduled batch 
processing applications. Administered Connections are used to schedule daily or 
weekly sessions originating from this application.
Ta b l e  9 6 .
Channel Type Number of Channels Data Rate
H0 6 384 Kbps
H11 24 1536 Kbps
H12 30 1920 Kbps
NXDS0 (T1) 2-24128–1536 Kbps
NXDS0 (E1) 2-31 128–1984 Kbps 
						

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Primary data connectivity. Permanent data connections (those always active 
during business hours), such as interconnections between local area networks 
(LANs), are well suited for DEFINITY ECS when ISDN-PRI endpoints are used. 
The ISDN end-to-end monitoring and the endpoint’s ability to react to failures 
provide for critical data availability needs. With ISDN, endpoints can detect 
network failures and initiate backup connections through the switch; ISDN 
endpoints can also establish additional calls when extra bandwidth is needed.
Any failures not automatically restored by DEFINITY ECS are signaled to the 
endpoint application, which can initiate backup data connections over the same 
PRI endpoint. DEFINITY ECS routes the backup data connections over alternate 
facilities if necessary.
Networking
All of the wideband networking is over ISDN-PRI facilities (and the emulation of 
them by ATM-CES) but may connect to a variety of networks, other domestic 
interexchange carriers’ services, private line, RBOC services, and services in 
other countries.
ISDN-PRI trunk groups and channel
allocation
Only ISDN-PRI trunks (and the emulation of them by ATM-CES) support 
wideband calls to the network. Wideband’s bandwidth requirements have 
necessitated modification of the algorithms by which trunks look for clear 
channels. The following section describes the search methods and their 
relationship to the available wideband data services.
Facility lists
A wideband call accessing the network must reside on a single ISDN-PRI facility. 
Trunks within a trunk group must be organized based on the facility on which they 
reside. This is accomplished by compiling a facility list as trunks are administered 
to a trunk group; if a trunk is added to a trunk group from a facility not already on 
that trunk group’s list, that facility is added to the list in an order based on the 
facility’s signaling group number and interface identifier. In other words, the 
facility list is compiled in an ascending order based first on signaling group 
number and second on the interface identifier assigned to the facility within the 
signaling group. For example, if three facilities having signaling group/interface 
identifier combinations of 1/1, 1/2, and 2/1 were associated with a trunk group, 
then a call offered to that trunk group would search those facilities in the order as 
they were just listed. Also note that since trunks within a given facility can span 
several trunk groups, a single facility can be associated with several different 
trunk groups. 
						

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Given this facility list concept, the algorithms have the ability to search for trunks, 
by facility, in an attempt to satisfy the bandwidth requirements of a given 
wideband call. If one facility does not have enough available bandwidth to support 
a given call, or it is not used for a given call due to the constraints presented in the 
following section, then the algorithm searches the next facility in the trunk group 
for the required bandwidth (if there is more than one facility in the trunk group).
In addition to searching for channels based on facilities and required bandwidth, 
Port Network (PN) preferential trunk routing is also employed. This PN routing 
applies within each algorithm at a higher priority than the constraints put on the 
algorithm by the parameters listed later in this section. In short, all facilities that 
reside on the same PN as the originating endpoint are searched in an attempt to 
satisfy the bandwidth of a given call, prior to searching any facilities on another 
PN.
Direction of trunk/hunting within facilities
The algorithms have the ability to select trunks from low B-channel to high 
B-channel or from high B-channel to low B-channel with an ISDN facility. This is 
a per ISDN trunk group option, but infers the direction of search within all ISDN 
facilities (or portions of those facilities) administered within that trunk group. This 
is necessary so the selection of trunks are not prone to as much glare as they 
otherwise would be if trunks were chosen in the same direction by both user and 
network sides of the ISDN interface. Note that in previous DEFINITY ECS 
releases, the order in which trunks were selected, whether through linear or 
circular hunting, would always be with respect to the order in which trunks were 
administered within the trunk group. Now, with the support of wideband services, 
all trunks within an ISDN trunk group optioned for wideband are ordered based 
on this new “direction of trunk/hunt with facilities” parameter, and without regard 
to the order in which trunks are administered within the trunk group. If an ISDN 
trunk group is not optioned for wideband, then a cyclical trunk hunt based on the 
administration of trunks within the trunk group is still available.
H11
When a trunk group is administered to support H11, the algorithm to satisfy a call 
requiring 1,536 Kbps of bandwidth uses a fixed allocation scheme. That is, the 
algorithm searches for an available facility using the following facility-specific 
channel definitions.
nT1: H11 can only be carried on a facility without a D-channel being 
signaled in an NFAS arrangement (B-channels 1-24 are used).
nE1: Although the 1,536-kbps bandwidth could be satisfied using a number 
of fixed starting points (for example, 1, 2, 3, etc.) the only fixed starting 
point being supported is 1. Hence, B-channels 1–15 and 17–25 are always 
used to carry an H11 call on an E1 facility. 
						

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If the algorithm cannot find an available facility within the trunk group that meets 
these constraints, then the call is blocked from using this trunk group. In this case, 
the call may be routed to a different trunk group preference via Generalized Route 
Selection (GRS), at which time, based on the wideband options administered on 
that trunk group, the call would be subject to another hunt algorithm (that is, either 
the same H11 algorithm or perhaps an N x DS0 algorithm described in a later 
paragraph).
This same hunt algorithm, when offered any other call (other than a 1,920-kbps 
call) attempts to preserve idle facilities by selecting trunk(s) in a partially 
contaminated facility if one exists. If the bandwidth required by this call cannot be 
satisfied by any partially contaminated facility, then the call is placed on available 
trunk(s) within an idle facility, thus contaminating the facility. Again, facilities are 
selected via the trunk group’s facility list and with PN preference, and trunk(s) 
within a facility are selected based on the direction of channel search 
administered. Note that on a T1 facility, a D-channel is not considered a busy 
trunk and results in a facility with a D-channel always being partially 
contaminated. On an E1 facility, however, a D-channel is not considered a busy 
trunk because H11 and H12 calls may still be placed on that facility; an E1 facility 
with a D-channel and idle B-channels is considered an idle facility.
H12
Since H12 is 1,920 Kbps which is comprised of 30 B-channels, a 1,920-kbps call 
can only be carried on an E1 facility. As with H11, the hunt algorithm uses a fixed 
allocation scheme with channel 1 being the fixed starting point. Hence, an H12 
call always is carried on B-channels 1 to 15 and 17 to 31 on an E1 facility (as 
illustrated in the following table). When offered any other call (other than a 
1,536-kbps call), the algorithm behaves as it does when H11 is optioned.
H0
When a trunk group is administered to support H0, the algorithm to satisfy a call 
requiring 384 Kbps of bandwidth also uses a fixed allocation scheme. Unlike the 
H11 fixed scheme which only supports a single fixed starting point, the H0 fixed 
DS0s Comprising Each Channel
FacilityISDN
Interface H11 H12
T1
T123B + D
24B (NFAS)-
1-24-
-
E1
E130B + D
31B (NFAS)1-15, 17-25
1-15, 17-251-15, 17-31
1-15, 17-31 
						

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scheme supports four (T1) or five (E1) fixed starting points. The H0 algorithm 
searches for an available quadrant within a facility based on the direction of trunk 
or hunt administered. If the algorithm cannot find an available quadrant within any 
facility allocated to this trunk group, then the call is blocked from using this trunk 
group. Again, based on GRS administration, the call may route to a different trunk 
group preference and be subject to another algorithm based on the wideband 
options administered.
This same trunk or hunt algorithm, when offered any narrowband or N x DS0 call, 
attempts to preserve idle quadrants by choosing a trunk(s) in a partially 
contaminated quadrant if one exists. If a partially contaminated quadrant capable 
of carrying the call does not exist, then the call is placed on available trunk(s) 
within an idle quadrant, thus contaminating the quadrant. Again, facilities are 
selected via the trunk group’s facility list and with PN preference, and a trunk(s) 
within a facility is selected based on the direction administered. Note that a 
D-channel is considered a busy trunk and results in the top most quadrant of a T1, 
B-channels 19 to 24, always being partially contaminated. This is not true for 
NFAS.
If this H0 optioned trunk group is also administered to support H11, H12, or N x 
DS0, then this algorithm also attempts to preserve idle facilities. In other words, 
when offered a narrowband, H0, or N x DS0 call, the algorithm searches 
partially-contaminated facilities before it searches to idle facilities.
N x DS0
For the N x DS0 multi-rate service, a trunk group parameter determines whether a 
floating or a flexible trunk allocation scheme is to be used. The algorithm to 
satisfy an N x DS0 call is either floating or flexible.
nFloating (Contiguous) — In the floating scheme, an N x DS0 call is placed 
on a contiguous group of B-channels large enough to satisfy the requested 
bandwidth without any constraint being put on the starting channel (that is, 
no fixed starting point trunk).
nFlexible — In the flexible scheme, an N x DS0 call is placed on any set of 
B-channels as long as the requested bandwidth is satisfied. There is 
absolutely no constraint such as contiguity of B-channels or fixed starting 
points. Of course, as with all wideband calls, all the B-channels comprising 
the wideband call must reside on the same ISDN facility.
Regardless of the allocation scheme employed, the N x DS0 algorithm, like 
the H11 and H12 algorithms, attempts to preserve idle facilities when 
offered B, H0, and N x DS0 calls. This is important so that N x DS0 calls, 
for large values of N, have a better chance of being satisfied by a given 
trunk group. However, if one of these calls cannot be satisfied by a 
partially-contaminated facility and an idle facility exists, a trunk on that 
idle facility is selected, thus contaminating that facility.