Lucent Technologies Release 7 Manual Do Utilizador
DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
Maintenance for R7r
555-230-126
Issue 4
June 1999
Hardware Configurations
2-17
Duplication: Reliability Options
2
Duplication: Reliability Options
Standard Reliability Option
On Standard Reliability systems, the 512-time-slot TDM bus is divided into two
duplicate 256-time-slot buses, A and B. Call traffic is shared between the two
buses. The first 5 time slots on each bus are reserved for the control channel,
which is active on only one of the two buses at a time. Likewise, the next 17 time
slots are reserved for carrying system tones. The tone times slot are not
necessarily on the same bus (A or B) as the control channel. If any failure takes
place that affects the ability of the active control or tone time slots to function, the
other bus becomes active for those time slots.
duplicate 256-time-slot buses, A and B. Call traffic is shared between the two
buses. The first 5 time slots on each bus are reserved for the control channel,
which is active on only one of the two buses at a time. Likewise, the next 17 time
slots are reserved for carrying system tones. The tone times slot are not
necessarily on the same bus (A or B) as the control channel. If any failure takes
place that affects the ability of the active control or tone time slots to function, the
other bus becomes active for those time slots.
High Reliability Option
High Reliability systems duplicate components that are critical to the viability of
the system as a whole to prevent a single failure from dropping all service:
the system as a whole to prevent a single failure from dropping all service:
■
PPN control carrier and carrier power units (OLSs)
■
All SPE circuit packs: Processor, Memory, MSSNET, Disk, Tape, SYSAM,
Duplication Interface, and carrier power units (OLSs)
Duplication Interface, and carrier power units (OLSs)
■
PPN Tone Clock circuit pack (EPN Tone-Clocks are not duplicated)
■
TDM buses (described above)
In addition to the above, the following are duplicated in Center Stage Switch
(CSS) configurations:
(CSS) configurations:
■
The PPN to CSS fiber link (consisting of the PPN Expansion Interface
circuit packs, the Switch Node Interface circuit packs that connect to the
PPN EIs, and cabling from the PPN EI to the CSS)
circuit packs, the Switch Node Interface circuit packs that connect to the
PPN EIs, and cabling from the PPN EI to the CSS)
■
Switch Node Clocks (SNCs) (two; on each Switch Node carrier)
The duplicated SPEs operate in active/standby fashion. Interchanges of the SPE
and of PPN Tone-Clocks operate independently unless induced by use of the
SPE-select switches. The 2 SNCs on each Switch Node carrier also operate in an
active/standby manner.
and of PPN Tone-Clocks operate independently unless induced by use of the
SPE-select switches. The 2 SNCs on each Switch Node carrier also operate in an
active/standby manner.
The duplicated fiber link between the PPN EIs and the CSS (the cable may
actually be metallic) do not use an active/standby strategy. Instead, both links
simultaneously carry active call traffic and control connectivity in an equally
distributed load-sharing manner. If a component fails one of these fiber links, all
connectivity over it on it is torn down, resulting in some dropped calls and control
and application links. Links and subsequent call service is immediately
re-established over the other EI fiber link.
actually be metallic) do not use an active/standby strategy. Instead, both links
simultaneously carry active call traffic and control connectivity in an equally
distributed load-sharing manner. If a component fails one of these fiber links, all
connectivity over it on it is torn down, resulting in some dropped calls and control
and application links. Links and subsequent call service is immediately
re-established over the other EI fiber link.