Maintenance-Object Repair Procedures
555-233-143
8-1248 Issue 1 May 2002
Duplication Impact
The Packet Interface circuit is a single point of failure in a duplex-reliability system
(with unduplicated IPSIs). If not acceptable, a S8700 Multi-Connect customer can
upgrade to a high- or critical-reliability system (with duplicated IPSIs). Figure 8-76
shows a S8700 Multi-Connect configuration with duplicated IPSIs. The following
concepts apply only to duplicated IPSIs.
■ Packet-bus connection
In a high- or critical-reliability system (duplicated IPSIs), the standby IPSI’s
Packet Interface circuit cannot access the packet bus to write data except
during a planned IPSI interchange or when the Peer Link test (#888) is run.
Consequently, the Maintenance Loop-Around test (#886) — requiring
access to the packet bus — is not run on the standby IPSI’s Packet
Interface circuit.
■ IPSI interchange
Severe Packet Interface circuit faults causing system and application links
to go down are detected within 1 second. A fatal fault error message is
generated, and the Packet Interface maintenance software attempts to run
the Packet Interface Reset test. In a high- or critical-reliability system, this
results in a requested IPSI interchange (instead of a Packet Interface
reset) since stable calls are preserved across the interchange.
Maintenance-Object Interactions
■ Packet Bus maintenance
A Packet Interface circuit physically interacts with the PKT-BUS. So, for
certain types of Packet Interface errors, it may be difficult to isolate faults to
one or the other component. In each of these cases, Packet Interface
maintenance forwards an error report to packet-bus maintenance, where it
records a packet-bus fault in the hardware error log and runs appropriate
Packet Bus tests.
■ Packet Interface maintenance
The operation of the IPSI circuit pack’s Packet Interface circuit affects the
operation and maintenance of other circuit packs connected to the packet
bus. This includes:
1. BRI applications (BRI-PT)
2. Universal DS1 applications (UDS1) for ISDN/PRI applications
3. Expansion Interface circuit pack maintenance (EXP-INTF)
Some packet errors may require examination of the Packet Interface
circuit’s operating status. To obtain this information:
■ Examine the Error and Alarm Logs for PKT-INT entries. You must
determine which PKT-INT the link is accessing.
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