PM8610-BIAP PMC [PMC-Sierra, Inc], PM8610-BIAP Datasheet - Page 65

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

10.1.7
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2000168, Issue 3
Table 12 shows a DS3 tributary mapped within the first synchronous payload envelope, SPE1.
The V5 indicator pulse identifies the V5 octet. The DS3 framing format does not follow an 8KHz
frame period so the floating DS3 multi-frame located by the V5 indicator, shown in heavy border
grey region in Table 12, will jump around relative to the H1 frame on every pass. In fact the V5
indicator will often be asserted twice per H1 frame, as is shown by the second V5 octet in Table
12. The V5 indicator and payload signals indicate negative and positive rate adjustments which
are carried out by either putting a data byte in the H3 octet or leaving empty the octet after the H3
octet.
Table 12 DS3 Framing Format
Because the DS3 tributary rate is less than the rate of the grey region, padding octets are
interleaved with the DS3 tributary to make up the difference in rate. Interleaved with every DS3
multi-frame are 35 stuff octets, one of which is the V5 octet. These 35 stuff octets are spread
evenly across seven DS3 subframes. Each DS3 subframe is eight blocks of 85 bits. The 85 bits
making up a DS3 block are padded out to be 11 octets. Table 13 shows the DS3 block 11 octet
format where R indicates a stuff bit, F indicates a DS3 framing bit and I indicates DS3
information bits. Table 14 shows the DS3 multi-frame format that is packed into the grey region
of Table 12. In this table V5 indicates the V5 octet which is also a stuff octet, R indicates a stuff
octet and B indicates the 11 octet DS3 block. Each row in Table 14 is a DS3 multi-frame. The
DS3 multi-frame stuffing format is identical for 5 multi-frames and then an extra stuff octet after
the V5 octet is added every sixth frame.
Table 13 DS3 Block Format
ROW
1
2
3
4
5
6
7
8
9
Octet #
Data
DS3 Tributary Mapping
SPE COL #
SBI COL#
1,4,7,10
Unused
Unused
Unused
Unused
Unused
Unused
Unused
Unused
Unused
1
RRRFIIII
13
H1
H2
H3
Linkrate
Unused
Unused
Unused
Unused
Unused
2
8*I
3
8*I
DS3
1
16
V5
DS3
DS3
DS3
DS3
DS3
DS3
DS3
DS3
8*I
4
5
8*I
DS3
2-56
DS3
DS3
DS3
DS3
DS3
DS3
DS3
DS3
DS3
6
8*I
SBS Telecom Standard Product Data Sheet
DS3
57
184
DS3
DS3
DS3
DS3
DS3
DS3
DS3
V5
DS3
7
8*I
8
8*I
DS3
58-84
DS3
DS3
DS3
DS3
DS3
DS3
DS3
DS3
DS3
9
8*I
10
8*I
DS3
Col 85
268
DS3
DS3
DS3
DS3
DS3
DS3
DS3
DS3
DS3
11
8*I
Preliminary
65