PM8610-BIAP PMC [PMC-Sierra, Inc], PM8610-BIAP Datasheet - Page 297

• Manufacturer Part Number: PM8610-BIAP
• Description: SBS Telecom Standard Product Data Sheet Preliminary
• Manufacturer: PMC [PMC-Sierra, Inc]

13.2.3
13.3
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2000168, Issue 3
The SBS and NSE support another mode of operation that has lower latency and lower power
when not switching at the DS0 level. In this mode, both of these devices become a column switch
rather than a DS0 switch. This saves software configuration since only one row of the switch
configuration RAMs has to be configured rather than all nine rows.
When switching DS0 through the system the SBS must store an entire frame of DS0s before
routing them to the destination to allow for the last DS0 of a frame to be switched to the first DS0
of the output. When doing column switching, only one row of the SBI structure needs to be stored
before switching can take place.
The same diagram from the previous section can be used here. The following timing diagram
shows the system timing for this mode of operation.
Figure 23 Non DS0 Switch Timing
SBS#2 OCMP.INT
Switch Setting Algorithm
NSE/SBS fabrics require an algorithm to map from customers’ connection requirements to
settings in the switch function control registers in these devices. Four constraints apply to this
algorithm:
SBS#1 TCMP.INT
NSE RC1FP.INT
SBI Frame Time
SBS RC1FP.INT
SBS OC1FP.INT
SBS/NSE Non-DS0 Level Switching with SBI336 Devices
SBS IC1FP.INT
SBS#2 OCMP
NSE CMP.INT
SBS#1 TCMP
Internal Sigs
NSE CMP
C1FP
0us
250us
SBS Telecom Standard Product Data Sheet
500us
Preliminary
297