PM8611-BIAP PMC [PMC-Sierra, Inc], PM8611-BIAP Datasheet - Page 53

• Manufacturer Part Number: PM8611-BIAP
• Manufacturer: PMC [PMC-Sierra, Inc]

10.1.13 SBI336 Multiplexing Structure
10.2
10.3
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Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2010883, Issue 2
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SBI Column
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SPE Column
Table 20 Structure for Carrying Multiplexed Links in SBI336
Table 20 shows how 12 SPEs are multiplexed into a 77.76 MHz SBI336 bus. The structure is
exactly the same as byte interleaving four 19.44 MHz SBI buses. 1,SPE1 identifies SPE1 from
the first SBI equivalent bus, 2,SPE1 identifies SPE1 from the second SBI equivalent bus, and so
on. All tributary mapping formats are exactly the same as for the 19.44 MHz SBI bus with the
only difference that there are four times the number of tributaries. Tributary numbering appends
the equivalent SBI number to the original SBI numbering. For example, the first T1 in a SBI bus
would be numbered T1 #1,1 whereas the first T1 in a SBI336 bus would be numbered T1 #1,1,1.
Likewise the second T1 in a SBI bus would be T1 #2,1 whereas the second T1 in a SBI336 bus
would be T1 #2,1,1.
Incoming SBI336 Timing Adapter
The Incoming SBI336 Timing Adapter (ISTA) provides a multiplexing function of four incoming
19.44 MHz SBI or TelecomBuses into a 77.76 MHz SBI336 or TelecomBus. This involves simple
column multiplexing of the four incoming SBI or TelecomBuses. The timing adapter block also
provides a transparent mode when the incoming interface is already in SBI336 or 77.76 MHz
TelecomBus format.
When the SBS is connected to an 19.44 MHz SBI physical layer device, the justification request
signal, JUST_REQ, is an input to the SBS and is aligned to the outgoing bus. This block re-
aligns the justification request signal from the outgoing frame alignment, marked by OC1FP, to
the internal incoming SBI336 frame alignment. When the SBS is connected to a 19.44 MHz SBI
link layer device or any 77.76 MHz SBI336 device, no re-alignment of the justification request is
required by this block.
CAS Expanders
The Channel Associated Signaling Expander blocks, ICASE and OCASE, pull the CAS
information from the SBI336 formatted bus on a tributary basis so that it can be switched through
the memory switch with the DS0 data. For tributaries enabled for DS0 switching, the CAS bits
are double buffered on a signaling multiframe boundary and repeated along side the tributary data
for the duration of the multiframe. This function is enabled on a per tributary basis and can be
used for T1 and E1 tributaries simultaneously across SBI SPEs. This block adds one T1
multiframe (24 frames) or one E1 multiframe (16 frames) of latency to the CAS bits.
24 25 26
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2
C1 -
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60 61
5 6
1,SPE1 2,SPE1
1,SPE1 2,SPE1
1,SPE1 2,SPE1
62
6
63
3,SPE1 4,SPE1 1,SPE2 2,SPE2 3,SPE2 4,SPE2
3,SPE1 4,SPE1 1,SPE2 2,SPE2 3,SPE2 4,SPE2
3,SPE1 4,SPE1 1,SPE2 2,SPE2 3,SPE2 4,SPE2
6
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6
SBSLITE™ Telecom Standard Product Data Sheet
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6
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1078 1079 1080
2,SPE3 3,SPE3 4,SPE3
2,SPE3 3,SPE3 4,SPE3
2,SPE3 3,SPE3 4,SPE3
90
Preliminary
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90
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