Avaya 03-300430 User Manual

The EXP-PN MO is responsible for overall maintenance of an Expansion Port Network (EPN) 
and monitors cross-cabinet administration for compatible companding across the 
circuit-switched connection. The focus of EPN maintenance is on the EI, the ATM’s EI, or the IP 
Server Interface (IPSI) circuit pack that is acting as the Expansion Archangel link in an EPN. 
EXP-INTF or ATM-EI or IP-SVR covers maintenance of the EI, ATM EI, or IPSI circuit pack, 
while EXP-PN covers a much broader area of activities and problems on an EPN. The alarming 
strategy for EXP-PN is fairly simple and does not make use of any failure analysis routine for 
spawning maintenance actions. EXP-PN alarming is based on the availability of an EPN for 
service and the EPN’s response to various recovery actions.
When investigating alarms logged against an EPN, problems involving the EI, an ATM EI, or an 
IPSI circuit pack acting as the Expansion Archangel; problems that may involve loss of 
communication between the EPN and the media server should be investigated. This could 
ultimately include fiber links (FIBER-LK), DS1 converter circuit packs (DS1C-BD), SNI circuit 
packs (SNI-BD) and Switch Node Configurations (SN-CONF) for CSS. For ATM, this could 
include the PN ATM EI (ATM-EI) circuit pack, the ATM switch (ATM-NTWK), and EPN ATM EI 
(ATM-EI) circuit pack. For TN2312 IPSI circuit packs this could include IP-SVR or IPSV-CTL 
maintenance objects. 

While not an exhaustive discussion of PN recovery actions, this section describes at a high level 
the causes and effects of PN restarts so that these Error Log events can be understood.

PN Warm Restart (PN Reset Level 1) is generally performed on a PN when the recovery of that 
PN can be accomplished in less than 30 seconds. When possible, Warm Restart minimizes the 
work required to reinitialize a PN and reduces the impact of a PN failure by avoiding the longer 
and highly-destructive PN Cold Restart. The primary cause of PN restarts is failure of the link 
from the media server to the PN due to a hardware fault in the link’s path. For most hardware 
failures this link (and thus the PN) cannot be recovered until the failed hardware is replaced. 
However, several failure modes provide hardware redundancy, allowing the link to be recovered 
quickly. For instance in duplicated systems, the failure of a Packet Interface circuit pack causes 
an IPSI interchange that allows the link to be recovered quickly over the newly-active Packet 
Interface. Or on a Center Stage Switch with multiple fibers interconnecting the switch nodes, a 
link carried on one fiber can be rerouted over another fiber.

1. Investigate errors against EXP-PN and EXP-INTF.

EXP-PN

MAJ

Expansion Port Network