PM5366-PI PMC-Sierra, Inc., PM5366-PI Datasheet - Page 73

• Manufacturer Part Number: PM5366-PI
• Description: HIGH DENSITY 84/63 CHANNEL VT/TU MAPPER AND M13 MULTIPLEXER
• Manufacturer: PMC-Sierra, Inc.

PRELIMINARY
DATASHEET
PMC-2010672
9
9.1 Transparent Virtual Tributaries
PROPRIETARY AND CONFIDENTIAL
FUNCTIONAL DESCRIPTION
The TEMAP-84 supports a total throughput of 155.52Mbit/s (including overhead)
in both transmit (a.k.a. egress) and receive (a.k.a. ingress) directions. The
bandwidth is divided into three approximately equal data streams, each
independently configured relative to the others. Configurations include, but are
not limited to:
Transparent virtual tributaries (TVTs) are supported when performing
VT1.5/TU11 or VT2/TU12 mapping into the Telecom Bus and the SBI Bus is
being used. Conceptually, a TVT is passed straight from the Telecom Bus to the
SBI Bus (and visa versa) with no knowledge of the mapping protocol or T1/E1
framing.
On the SBI Add Bus there are two methods of indicating transmit pointers. If the
ETVTPTRBYP or EPTRBYP bit is logic 1, the SAV5 input must indicate the
location of the V5 byte and the V1/V2 bytes need not be valid at the SBI Add
Bus. If both ETVTPTRBYP and EPTRBYP bit are logic 0, the V1/V2 bytes at the
SBI Add Bus must contain a pointer to the V5 byte. If the Egress VTPP is
bypassed (i.e. EVTPPBYP bit logic 1), the entire virtual tributary including V1-V5
is transferred without modification. The LAV5 output reflects the byte position
indicated by the SAV5 input. Alternately, the V1/V2 bytes may be required to
contain a valid pointer. When the Egress VTPPs are not bypassed, both a new
V1/V2 value is encoded and a LAV5 output pulse is generated to match.
The configuration of the Ingress VTPP determines the requirements for the
Telecom Drop Bus. If the Ingress VTPP is bypassed (i.e. IVTPPBYP is logic 1),
the J1 byte must be at pointer 522 decimal, the LDV5 input must indicate the
location of the V5 byte, encoding of V1/V2 is purely discretionary and the entire
virtual tributary including V1-V5 is transferred without modification. If IVTPPBYP
is logic 0, V1/V2 must contain a valid pointer. The V1/V2 will be modified in the
process of mapping the TVT into the SBI Drop Bus, which by definition has a
SPE alignment equivalent to a pointer of 522 decimal. If IVTPPBYP is logic 0,
tributary and path pointer justifications on the Telecom Drop Bus will result in
• 28 1.544 Mbit/s or 21 2.048 Mbit/s tributaries multiplexed into a
• A single 44.736Mbit/s or 34.386Mbit/s stream. It may be a T3, E3
DS3 or mapped into a SONET/SDH structure.
or clear channel. The 44.736Mbit/s data stream may be mapped
into a SONET/SDH structure.
ISSUE 1
61
HIGH DENSITY 84/63 CHANNEL VT/TU MAPPER
AND M13 MULTIPLEXER
PM5366 TEMAP-84