
Multi-Service Access Device For Channelized Interfaces
Telecom Standard Product Data Sheet
Production
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990823, Issue 4
43
The S/UNI-MACH48 allows the SONET/SDH payload to be configured as a single STS-
48c/STM-16-16c or as any valid combination of STS-12c/STM-4c, STS-3c/STM-1, STS-1, and
DS3 channels. The STS-48c/STM-16-16c channel fills the entire bandwidth of the S/UNI-
MACH48 and is assigned to channel number 0. STS-12c/STM-4c channels can be assigned to
channels 0, 12, 24, and 36. STS-3c/STM-1 channels can be assigned within a range associated
with the STS-12 stream which it belongs to. STS-1/STM-0 and DS3 channels can be assigned to
any timeslot not already allocated to others but must also reside within the range of channel
values allocated to the STS-12 stream which it belongs to.
When used to implement an ATM UNI or NNI, the S/UNI-MACH48 frames to the ATM payload
using cell delineation. The ATM cell payloads are descrambled and are written to a four cell or
greater FIFO buffer. The per-channel FIFO size is scalable from 2 cells to 48 cells in size. The
total FIFO space available is 192 cells. The received cells are read from the FIFO using a 32-bit
wide UTOPIA Level 3 or POS-PHY Level 3 (clocked up to 104 MHz) datapath interface. Counts
of received ATM cells and erred ATM headers are accumulated for performance monitoring
purposes.
When used to implement packet transmission over a SONET/SDH link, the S/UNI-MACH48
extracts Packet over SONET (POS) and HDLC frames from the SONET/SDH synchronous
payload envelope and de-mapped DS3 streams. Frames are verified for correct construction and
size. The control escape and bit-stuffing characters are removed. The frame check sequence is
optionally verified for correctness and the extracted packets are placed in a receive FIFO. FIFO
size for each channel is scalable from 128 bytes to 3072 bytes. The total FIFO space available is
12,288 bytes. The received packets are read from the FIFO through a 32-bit POS-PHY Level 3
(clocked up to 104 MHz) system side interface. Valid and FCS erred packet counts are provided
for performance monitoring. The S/UNI-MACH48 Packet over SONET implementation is
flexible enough to support several link layer protocols, including HDLC, PPP and Frame Relay.
8.2
Transmit Direction
In the egress direction, the S/UNI-MACH48 transmits the SONET/SDH frame(s) via a parallel
TelecomBus interface at 77.76 MHz or a set of 777.6 Mbps LVDS compatible serial TelecomBus
links.
Each parallel TelecomBus interface can accommodate a set of four STS-12/STM-4 data streams
or an STS-48c/STM-16 data stream. The TelecomBus interface passes appropriate SONET/SDH
framing markers along with the data. This allows the S/UNI-MACH48 to interface seamlessly to
SONET/SDH framers such as the SPECTRA-2488, SPECTRA-622, and SPECTRA-4x155.
The outgoing LVDS compatible serial TelecomBus stream data is encoded in an extended set of
8B/10B characters and transferred onto two independent sets of 777.6 Mbps LVDS links.
Transport and payload frame boundaries, pointer justification events and alarm conditions are
marked by 8B/10B control characters. Two sets of links are available. One can be used for
working traffic and the other can be used for protection traffic.