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Empowering Intelligent Optical Networks

Product Brief

DANUBE

SONET/SDH STS-48/STM-16 Framer/Pointer Processor

Part Number S4805CBI11, Revision 1.5, January 2003

Overview and Applications

SONET Processing

The S4805 can be used in either SONET or SDH applications. On

the low-speed side, it can interface to 4 groups of either 1 STS-

12/STM-4 or 4 STS-3/STM-1 signals in each direction.

In the demultiplex direction, the S4805 accepts an STS-48/STM-

16 signal, either in 4-bit wide, 622 MHz or 16-bit wide, 155 MHz

format. There are then several modes of operation that the S4805

supports in the demultiplex direction.

For STS-48 only operation, the S4805 provides a full-bypass

mode, as well as a pointer processor bypass mode. In the full-

bypass mode, the S4805 simply passes the incoming STS-48/

STM-16 signal directly through to the demux output. Framing,

descrambling and TOH monitoring are performed off-line, in a

non-intrusive manner for monitoring purposes only. No pointer

processing, cross-connection or frame regeneration is performed.

In pointer processor bypass operation, the S4805 locates the

incoming STS-48/STM-16 frame, optionally descrambles the

data, and non-intrusively monitors the TOH. The STS-48/STM-16

signal is then passed directly to the frame generation block, in

which outgoing TOH overhead bytes can be provisionally regen-

erated, on a per function basis. Again, no pointer processing is

performed, and the cross-connect block is bypassed.

For applications requiring pointer processing, the S4805 locates

frame in the incoming STS-48/STM-16 signal, performs descram-

bling, monitors the TOH bytes, and then performs pointer pro-

cessing. The pointer processor provides a mode in which the

incoming TOH bytes transparently pass through the pointer pro-

cessor to the corresponding locations in the TOH of the outgoing

tributaries. The TOH bytes involved in this transparent pass-

through mode include the defined overhead bytes for the constitu-

ent STS-3/STM-1, STS-12/STM-4 or STS-48/STM-16 signals. A

192x48 cross-connect block is available after the pointer proces-

sor. This cross-connect can be used to select STS-1s from any of

the demuxed tributaries, tributaries from the low-speed mux

inputs, or tributaries from the DX and MX APS interfaces to place

into any one of the outgoing STS-1 time slots in any of the outgo-

ing signals in the demux direction. If this signal does not contain a

STS-48c/AU-4-16c payload, the S4805 can demultiplex the signal

to 4 groups of either 1 STS-12/STM-4 or 4 STS-3/STM-1 tributar-

ies. The selected tributaries then proceed in the demux direction

to frame generators that provisionally generate the TOH/SOH

bytes, perform scrambling, and output the data. Alternatively, the

overhead data can be transparently passed through the frame

generation block.

In the multiplex direction, the S4805 accepts a single STS-48/

STM-16 signal (4-bits wide, 622 MHz or 16-bit wide, 155 MHz), 4

serial STS-12/STM-4 (622 MHz) signals or 4 groups of 4 serial

(155 MHz) STS-3/STM-1 signals. There are several modes of

operation that the S4805 supports in the multiplex direction.

For STS-48 only operation, the S4805 provides a full-bypass

mode, as well as a pointer processor bypass mode. In the full-

bypass mode, the S4805 simply passes the incoming STS-48/

STM-16 signal directly through to the mux output. Framing,

descrambling and TOH monitoring are performed off-line, in a

non-intrusive manner for monitoring purposes only. No pointer

processing, cross-connection or frame regeneration is performed.

In pointer processor bypass operation, the S4805 locates the

incoming STS-48/STM-16 frame, optionally descrambles the

data, and non-intrusively monitors the TOH. The STS-48/STM-16

signal is then passed directly to the frame generation block, in

which outgoing TOH overhead bytes can be provisionally regen-

erated, on a per function basis. Again, no pointer processing is

performed, and the cross-connect block is bypassed.

For applications requiring pointer processing, the S4805 locates

the incoming STS-48/STM-16, STS-12/STM-4 or STS-3/STM-1

frames, descrambles the data, non-intrusively monitors the TOH/

SOH bytes and then performs pointer processing. The pointer

processor provides a mode in which the incoming TOH bytes

transparently pass through the pointer processor to the corre-

sponding locations in the TOH of the outgoing tributaries. The

TOH bytes involved in this transparent pass-through mode

include the defined overhead bytes for the constituent STS-3/

STM-1, STS-12/STM-4 or STS-48/STM-16 signals. A 192x48

cross-connect block is available after the pointer processor. This

cross-connect can be used to select STS-1s from the incoming

multiplex side signals, tributaries from the demux direction, or trib-

utaries from either the DX or MX APS interface. These selected

tributaries are then muxed into an STS-48/STM-16 signal. This

STS-48/STM-16 muxed signal then proceeds to a frame genera-

tor that provisionally generates the TOH/SOH bytes, performs

scrambling, and outputs the data. Alternatively, the overhead data

can be transparently passed through from the mux inputs to out-

put.

Low-Speed Interfaces

On the low-speed side, in both the mux and demux directions, the

S4805 supports either a 16-bit wide, 155 Mb/s STS-48/STM-16

signal, a 4-bit wide, 622 Mb/s STS-48/STM-16 signal, 4 serial

STS-12/STM-4 signals operating at 622 Mb/s or 4 groups of 4

serial STS-3/STM-1 signals operating at 155 Mb/s. The S4805 is

designed to bolt directly to fiber optic transceivers with built-in

clock data recovery.

(See figure below.)

High-Speed Interface

On the high-speed side, in both the mux and demux directions,

the S4805 supports either a 16-bit wide, 155 Mb/s or a 4-bit wide,

622 Mb/s STS-48/STM-16 signal.

Controller Interface

A high-speed microprocessor interface is provided for configura-

tion and monitoring. S4805 provides numerous automatic moni-

toring functions. It can be configured to provide an interrupt to the

control system, or it can be operated in a polled mode.

Applications:

• SONET/SDH add/drop multiplexers, terminal multiplexers, and

digital cross connects.

• WDM/DWDM Mux/Demux applications