Hello, community members!
I'd like to share some informations about SDH & PDH, and how to configure STM & E1 on Huawei RTN.
What is SDH ?
Synchronous Digital Hierarchy, it is a transmission protocol based on sending and receiving information in the form of digital bits on fiber cables,and we call it the optical transmission protocol
STM -1
Synchronous Transport Module level-1
Its data transfer rate is 155 Mbps, Put the bits into the Matrix,9 rows * 270 columns
The STM-1 base frame is structured with the following characteristics:
· Length: 270 column × 9 row = 2430 bytes
· Byte: 1-byte = 64kbit/s speech channel
· Duration (Frame repetition time): 125 μs i.e. 8000 frame/s
· Rate (Frame capacity): 2430 × 8 × 8000 = 155.520 Mbit/s
· Payload = 2349bytes × 8bits × 8000frames/sec = 150.336 Mbit/s
How to calculate the data rate STM-1 ?
STM-1 data rate = 9 rows * 270 columns * 8 bit / byte * 8000 frame / sec = 155.5 mbps.
VC-4 & VC-12
Vertical Containers of timeslots
Some Boards That Support STM-1 On RTN

SL1D/SL1DA
The SL1D/SL1DA is a 2xSTM-1 optical interface board. The SL1D/SL1DA can also provide STM-1 electrical ports by using SFP electrical modules. Besides all the functions provided by the SL1D, the SL1DA supports the K byte pass-through function.
Features
1- Receives and transmits 2xSTM-1 optical/electrical signals.
2- Optical ports Uses SFP optical modules to provide optical ports of Ie-1, S-1.1, L-1.1, and L-1.2 types. And Provides ITU-T G.957-compliant optical port specifications.
3- Electrical ports l Adopts SFP electrical modules. And The performance of the electrical ports comply with ITU-T G.703.
4- Supports the following loopback types: Outloopsat optical/electrical ports and Inloopsat optical/electrical ports and Outloopson VC-4 paths l Inloops on VC-4 paths.
5- OutbandDCN Provides a 3-, 9-, or 12-byte DCC channel over each SDH line port.
6- Protection Supported LMSP and Supported SNCP.

CQ1
CQ1boards are 4-port channelized STM-1 processing boards.
Features
1- Receives and transmits four channels of channelized STM-1 optical/ electrical signals.
2- Supportespacketservice types and Circuit emulation service (CES) E1 l ML-PPP E1.
3- Supporters Optical ports l Uses small form-factor pluggable (SFP) optical modules to provide optical ports of the Ie-1, S-1.1, L-1.1, and L-1.2 types. And Complies with ITU-T G.957.
4- Electrical ports l Uses SFP electrical modules. And Complies with ITU-T G.703.
5- OutbandDCN Each SDH line port can provide one data communications channel (DCC) that is composed of three DCC bytes, nine DCC bytes, or 12 DCC bytes.
6- InbandDCN Transmits DCN information over ML-PPP links.
7- Loopback Supports inloops at STM-1 ports. l Supports outloopsat STM-1 ports. l Supports inloopsover E1 channels. l Supports outloopsover E1 channels.
Steps To Connect STM-1 With Radio
1- Guaranteed E1 capacity on if Board

2- From Configuration Select PDH/SDH Service Management then choose new.

3- Select IF Board & Port & Source range For Source also Select STM Board & Port & Sink range For Sink

What is PDH ?
Plesiochronous Digital Hierarchy
It is a transmission protocol based on sending and receiving information in the form of the digital multiplexer (bit streams) that have the same bit rate and are derived from different clocks from different oscillators. Each will vary within tolerances of a few time periods. Hence it is called synchronous.
PDH has more than Standard
1- Europe (E).
2- America (T).
3- Japan (J).
1- Standard Europe (E) :
The data transfer rate is 2 megabits per second
E Types:
Including many versions E1,E2,E3,E4
E1 Capacity:
frame has 32 time slots
It takes 8000 frames/sec and 8 bits/byte
Date rate = 32 *8000*8 = 2.048 mbps.
E2 = 4 E1
E3 = 4 E2
E4 = 4 E3
Add Drop Multiplexer ADM
To convert from stm, E1 and vice versa
Some Boards That Support E1 On RTN
SP3S
The SP3S is a 16xE1 75-ohm/120-ohm tributary board.
Features
1- Receives and transmits E1 signals.
2- SP3S 75-ohm/120- ohm E1 port = 16 .
3- Loopback Supports in loops and outlooks E1 tributary ports.
4- Supported E1 retiming function.
5- Supported Cold reset and warm reset & Supported PRBS tests at E1 ports & Supported Queries of board manufacturing information & Queries of the board power consumption.
SP3D
The SP3D is a 32xE1 75-ohm/120- ohm tributary board.
Features
1- Receives and transmits E1 signals.
2- SP3D 75-ohm/120- ohm E1 port = 32.
3- Loopback Supports in loops and outlooks E1 tributary ports.
4- Supported E1 retiming function.
5- Supported Cold reset and warm reset & Supported PRBS tests at E1 ports & Supported Queries of board manufacturing information & Queries of the board power consumption
Steps to Create one E1 on Huawei RTN.
1- First, from Microwave link Configuration determine the number of E1 that you want to configure.
2- From configuration select PDH/SDH service management then choose new.
3- Select IF board for source.
4- Select E1 board for sink.
5- Set source timeslot range and Set sink timeslot range.
1- First, from Microwave Link Configuration determine the number of E1 that you want to create.

2- From Configuration Select PDH/SDH Service Management then choose new.

3- Select IF board for source.

4- Select E1 board for sink.

5- Set source timeslot range and Set sink timeslot range.

Summary Of Article
1-SDH & PDH is a transmission protocol based on sending and receiving information in digital.
2- SDH frame using Optical fiber and PDH using a copper cable (75 ohm or 120 ohm).
3- SDH data transfer rate is 155 Mbps, Put the bits into the Matrix,9 rows * 270 columns.
4- PDH frame has 32 time slotsIt takes 8000 frames/sec and 8 bits/byte Date rate = 32 *8000*8 = 2.048 mbps.
5- Some boards in RTN that support SDH (SL1D / SL1DA - CQ1) and their features.
6- Some boards in RTN that support PDH (SP3S - SP3D) and their features..
7- How to configure SDH & PDH on Huawei RTN with photos.


