Avaya S8700 Maintenance Manual page 1485

EXP-INTF (Expansion Interface Circuit Pack)
The TN570 or the TN776 Expansion Interface (EI) circuit pack provides a TDM-
and packet bus-to-fiber interface for the communication of signaling information,
circuit-switched connections, and packet-switched connections between
endpoints residing in separate port networks. EI circuit packs reside in the Port
Networks (PNs) and are connected via optical fiber links. An EI can be connected
to:
Another EI — in a direct-connect configuration
A DS1 converter in a DS1 CONV complex — used to remote an PN
A Switch Node Interface (SNI) — in a center stage switch (CSS)
configuration
A survivable remote EPN (SREPN)
In a CSS configuration with duplicated Port Network Connectivity (PNC), the
PPN's EI circuit packs reside in the Switch Node Carrier (see
8-767). In this case, the EI and SNI circuit packs may be connected via a metallic
cable instead of an optical fiber link. Metallic cable should be tested and replaced
in the same manner as optical fiber.
An PN-to-PN connection can be extended through a DS1 CONV complex. (See
Figure 8-38 on page
fiber links, the DS1 CONV is considered part of the fiber link. If diagnosis of the
problem points to fiber connectivity and a DS1 CONV circuit pack is part of the
connectivity, problems with the DS1 CONV circuit pack should be investigated
(see ''DS1 CONV-BD'' on page
diagnostics for the EI circuit pack via such tests as the Neighbor Query test
(#237), the Fiber Out-of-Frame test (#238), the Two-Way Transmission test
(#241), and the Packet Transmission test (#589).
In a critical-reliability system, the fiber link's are duplicated as part of PNC
duplication. In a high-reliability system with a CSS (Center Stage Switch) and
unduplicated PNC, a single point of failure between the media server and the CSS
is eliminated by duplicating each link, consisting of:
EI in the PN
SNI in the CSS to which the PN's EI connects
Physical metallic or fiber paths between them
These dual connections normally share the call-processing load. Should one of
these links fail, the entire load can be shifted to the operational link.
Figure 8-34 on page 8-764
unduplicated PNC, direct connect configuration.
555-233-143
8-768). When discussing problems that may be related to
8-683). The DS1 CONV circuit pack enters into
shows the location of the EI circuit packs in a typical
Figure 8-37 on page
Issue 1 May 2002 8-763