Lucent Technologies CBX 3500 Configuration Manual page 249

Beta Draft Confidential
Note – See the Switch Module Configuration Guide
and B-STDX 9000
support these Fast APS 1+1 options.
As traffic is rerouted from a working trunk to a protection trunk during a failure, the
switchover speed may be less than that provided by Intra-card APS 1+1.
Note – Point-to-multipoint (PMP) circuits are not supported by The Fast APS 1+1
option.
Unidirectional APS Over PNNI
There are two directional switching modes in APS 1+1 architecture: unidirectional
mode and bidirectional mode. In unidirectional mode, the head end makes a decision
on the selector position without regard to the K1/K2 bytes received from the tail end.
In bidirectional mode, the head end will consider the K1/K2 bytes received from the
tail end in deciding the selector position. Unidirectional APS is less disruptive and is
the default mode for the Bellcore GR-253-CORE standard.
APS over PNNI in unidirectional mode is supported for the 4-port OC-3c/STM-1,
1-port OC-12c/STM-4, and OC48/STM-16 modules on the GX 550 BIO1 module.
Special Considerations
Fast APS 1+1 on a CBX 500 — Configure the working and protection physical ports
on different IOMs. (See the Switch Module Configuration Guide
500, GX 550, and B-STDX 9000
ports on different IOMs in a CBX 500 switch.
Fast APS 1+1 on a GX 550 — Configure the working and protection physical ports
on different modules. (See the Switch Module Configuration Guide
500, GX 550, and B-STDX 9000
cell trunk between ports on different modules in a GX 550 switch.
Physical Port Provisioning
You provision Fast APS 1+1 on the physical port as follows:
•
•
ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000
for a listing of the minimum software and hardware versions that
Configure the physical port attributes on the working port. (The protection port is
automatically configured with the corresponding values.)
See the Switch Module Configuration Guide
for more information on configuring Fast APS 1+1 on CBX 500 and
B-STDX 9000
GX 550 switches.
for more information.) Configure an APS trunk between
for more information.) Configure an APS ATM direct
for CBX 3500, CBX 500, GX 550, and
Configuring Trunks
About APS
for CBX 3500, CBX 500, GX 550,
for CBX 3500, CBX
for CBX 3500, CBX
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