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Lucent Technologies DEFINITY Enterprise Communications Server Release 8.2 Instructions Manual
Lucent Technologies DEFINITY Enterprise Communications Server Release 8.2 Instructions Manual
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DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1.1 June 2000 Managing data calls 437 Wideband Switching 15 Typical uses A typical video application uses an ISDN-PRI interface to DS0 1 through 6 of the line-side facility. Refer to Figure 14 . Figure Notes Figure 14. Wideband Switching Video Application 1. Video application 2. Port 1 3. Port 2 4. ISDN terminal adaptor 5. Line-side ISDN-PRI 6. DEFINITY ECS 7. ISDN 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 1.1 June 2000 Managing data calls 438 Wideband Switching 15 Endpoint applications An endpoint application is the origination or destination of a wideband call. Endpoint application 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. 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. 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 an including 6 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 always are selected unless one or more B-channels are not in 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. Universal digital signaling level 1 circuit pack The UDS1 circuit pack is the interface for line-side and network facilities carrying wideband calls.
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1.1 June 2000 Managing data calls 439 Wideband Switching 15 Non-signaling configuration Wideband also can support configurations using non-signaling (non-ISDN-PRI) line-side T1 or E1 connections. The endpoints 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 (24 for a T1 facility and 32 for an E1 facility; both T1 and E1 use 2 channels for signaling purposes). 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 1.1 June 2000 Managing data calls 440 Wideband Switching 15 Guidelines and examples This section examines wideband and its components in relation to the following specific customer usage scenarios: nData backup connection nScheduled batch processing nPrimary data connectivity nNetworking 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. Primary data connectivity Permanent data connections (those always active during business hours), such as interconnections between 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.
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1.1 June 2000 Managing data calls 441 Wideband Switching 15 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 idle channels. The following section describes the search methods and their relationship to the available wideband data services. Facility lists The system always sends a wideband call over a single trunk group and a single DS1 facility (or other ISDN-PRI-capable facility). Since a trunk group may contain channels (trunk members) from several different DS1 facilities, the system maintains a facility list for each trunk group. A facility list orders the trunk members based on signaling group. If the system is using non-facility associated signaling groups with multiple DS1 facilities, the system sorts trunk members in that signaling group according to the interface identifier assigned to the corresponding DS1 facility. When searching for available channels for a wideband call placed over a given trunk group, the system starts with the channels in the lowest-numbered signaling group with the lowest interface identifier. If the system cannot find enough channels in a given signaling group with that interface identifier, it checks the next higher interface identifier. If no more interface identifiers are available in the current signaling group, the system moves its search to the channels in the next higher 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 1.1 June 2000 Managing data calls 442 Wideband Switching 15 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 You can tell the system to search for available channels in either ascending or descending order. These options help you reduce glare on the channels because the system can search for channels in the opposite direction to that used by the network. 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, and so forth), the only fixed starting point being supported is 1. Hence, B-channels 1-15 and 177-25 always are used to carry an H11 call on an E1 facility. If the algorithm cannot find an available facility within the trunk 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).
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1.1 June 2000 Managing data calls 443 Wideband Switching 15 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 shown 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 scheme supports 4 (T1) or 5 (E1) 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. 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 the system also attempts to preserve idle facilities. In other words, when offered a narrowband, H0, or N x DS0 call, the system searches partially-contaminated facilities before it searches to idle facilities. 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 1.1 June 2000 Managing data calls 444 Wideband Switching 15 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. There are additional factors to note regarding specific values of N and the NxDS0 service: — N = 1 — this is considered a narrowband call and is treated as any other voice or narrowband-data (B-channel) call. — N = 6 — if a trunk group is optioned for both H0 and N x DS0 service, a 384-kbps call offered to that trunk group is treated as an H0 call and the H0 constraints apply. If the H0 constraints cannot be met, then the call is blocked. — N = 24 — if a trunk group is optioned for both H11 and N x DS0 service, a 1,536-kbps call offered to that trunk group is treated as an H11 call and the H11 trunk allocation constraints apply. — N = 30 — if a trunk group is optioned for both H12 and N x DS0 service, a 1,920-kbps call offered to that trunk group is treated as an H12 call and the H12 trunk allocation constraints apply.
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1.1 June 2000 Managing data calls 445 Wideband Switching 15 Glare and blocking Glare prevention Glare occurs when both sides of an ISDN interface select the same B-channel for call initiation. For example, a user side of an interface selects the B-channel for an outgoing call and, before the switch receives and processes the SETUP message, the switch selects the same B-channel for call origination. Since any single wideband call uses more channels, the chances of glare are greater. With proper and careful administration, glare conditions can be reduced. To reduce glare probability, the network needs to be administered so both sides of the interface select channels from opposite ends of facilities. This is called linear hunting, ascending or descending. For example, on a 23B+D trunk group, the user side could be administered to select B-channels starting at channel 23 while the network side would be administered to start selecting at channel 1. Using the same example, if channel 22 is active but channel 23 is idle, the user side should select channel 23 for re-use. Blocking prevention Blocking occurs when insufficient B-channels required to make a call are available. Narrowband calls require only one channel so blocking is less likely than with wideband calls which require multiple B-channels. Blocking also occurs for wideband calls when bandwidth is not available in the appropriate format (that is, fixed, floating, or flexible). To reduce blocking, the switch selects trunks for both wideband and narrowband calls to maximize availability of idle fixed channels for H0, H11, and H12 calls and idle floating channels for N x DS0 calls that require a contiguous bandwidth. The strategy for preserving idle channels to minimize blocking depends on the channel type. The chances for blocking are reduced if you use a flexible algorithm, assuming it is supported on the other end. Channel Type Blocking Minimization Strategy H0 Preserve idle quadrants H11 Preserve idle facilities H12 Preserve idle facilities Flexible NxDS0 Preserve idle facilities Floating NxDS0 Preserve idle facilities as first priority
DEFINITY ECS Release 8.2 Administrator’s Guide 555-233-506 Issue 1.1 June 2000 Managing data calls 446 Wideband Switching 15 Administering Wideband Switching Before you start You need a DS1 Converter circuit pack. Refer to the DEFINITY ECS System Description for more information on the circuit pack. Instructions To administer wideband switching: 1. On the Access Endpoint screen, administer all fields. Refer to ‘‘ Access Endpoint’’ on page 481 for more information. 2. On the PRI Endpoint screen, administer all fields. Refer to ‘‘ PRI Endpoint’’ on page 865 for more information. 3. On the ISDN Trunk Group screen, administer all fields. Refer to ‘‘ ISDN trunk group’’ on page 750 for more information. 4. On the Route Pattern screen, administer all fields. Refer to ‘‘ Route Pattern’’ on page 877 for more information. NOTE: The following is optional. 5. On the Fiber Link Administration, administer all fields. Refer to DEFINITY ECS Administration for Network Connectivity for more information. Considerations nFor wideband switching with non-ISDN-PRI equipment, you can use an ISDN-PRI terminal adapter.