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Lucent Technologies DEFINITY Enterprise Communication Server Release 8.2 Administrators Guide
Lucent Technologies DEFINITY Enterprise Communication Server Release 8.2 Administrators Guide
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DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1 April 2000 Features and technical reference 1587 Wideband Switching 20 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.)
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1 April 2000 Features and technical reference 1588 Wideband Switching 20 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
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1 April 2000 Features and technical reference 1589 Wideband Switching 20 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
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1 April 2000 Features and technical reference 1590 Wideband Switching 20 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.
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1 April 2000 Features and technical reference 1591 Wideband Switching 20 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.
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1 April 2000 Features and technical reference 1592 Wideband Switching 20 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
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1 April 2000 Features and technical reference 1593 Wideband Switching 20 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.
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1 April 2000 Features and technical reference 1594 Wideband Switching 20 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.
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1 April 2000 Features and technical reference 1595 Wideband Switching 20 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
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1 April 2000 Features and technical reference 1596 Wideband Switching 20 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.