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255-700-714R11.0 2-3
PacketStar
®
PSAX 1-Port Channelized OC-3/STM-1 CES Module User Guide , Issue 1 Release 11.0.0
Chapter 2 Module Description
Module Specifications
Automatic Protection Switching (APS) Feature
Module pairs may be loaded in all I/O slots of all PSAX chassis. In the
PSAX 1250 chassis (1.2 Gbps backplane capacity), you may load a maximum
of 8 modules in a non-APS configuration, or a maximum of 4 pairs in an APS
configuration.
To set up the APS feature, you must install two 1-Port Channelized
OC-3/STM-1 CES modules as an adjacent pair into the PSAX chassis. The left
module of the pair must be installed in an odd numbered slot. One module of
the pair functions as the primary module (working module), and the other
module of the pair functions as the backup module (protection module). The
APS implementation is compliant with the GR-253-CORE standard and sup-
ports linear, non-revertive APS, in both bidirectional and unidirectional
modes. Non-revertive, or non-automatic, switchback reduces a service inter-
ruption due to link failure from two interruptions to one interruption.
SPVC Prioritization Support
The PSAX 1000 and the PSAX 4500 systems provide efficient transport of
traffic transport between cell sites and the mobile switching centers (MSCs).
In cellular phone transmissions, all traffic between the cell sites and the MSC
is wireless backhaul. In North America, due to historical reasons, a cell site
supports multiple radio access technologies such as AMPS, TDMA, CDMA,
and GSM. To provide efficient statistical multiplexing gain, multiple DS1s are
grouped together using IMA over ATM in one IMA group. Furthermore, IMA
provides N:1 protection of the DS1 leased lines under many circumstances.
However, when one or more DS1s fail in the IMA group, enough bandwidth
might not be available to carry all cell site traffic from cell site to the MSC. In
the current dynamic CAC as implemented by the PSAX system, all SPVC and
SVC calls are cleared whenever one or more DS1s fail in an IMA group. PVC
connections are not affected; however, an IMA cell may get dropped but the
connection is reestablished immediately.
Module Specifications
Hardware Specifications
Table 2-1 provides the general physical hardware and environmental specifi-
cations for the PSAX I/O module.
Table 2-1. Physical Hardware Specifications for the PSAX I/O Module
Specification Description
Dimensions 17.3 cm H x 2.41 cm W x 24.1 cm D
(6.8 in. H x 0.95 in. W x 9.5 in. D)
Weight 0.34 kg (0.76 lb.)
Weight 0.3 kg (0.6 lb.) Multimode or Single-Mode
Weight 0.50 kg (1.1 lb.)
Weight 0.3 kg (0.6 lb.) Multimode or Single-Mode