Guide to SDH6-Performance Definitions
7-Network Synchronization.
Multi vendor environment
3-Unified Multiplexing Structure
4-Synchronous System
Synchronous multiplexing
5-Abundant Overhead Bit
Guide to SDH
All equipment in the network use the same clock source
Stuffing is not required for multiplexing
SDH multiplexing using pointer function
All byte visibility
High stability clock source required
10 stability clock source for Primary reference source
-11
E1
63 E1
Ptr
Unshaded areas are phase aligned, Phase alignment between the unshaded and shaded areas is defined by the pointer(Ptr) and is indicated by the arrow
SDH Mapping Structure(2)
E1
-Voice frequency=4 KHZ
-As Nayqust Theory sampling rate is twice the frequency rate=2*4=8000 HZ
-So the time for frequency = 1 = 0.125 msec = 125 micro second
-So STM1 frame period is 125 micro second.
-STM1 Frame contain 270 columns and 9 rows.
-So the total number of bytes per STM1 Frame = 270*9= 2430 Bytes.
-SO the total number of bit per STM1 Frame =2430*8= 19440 Bits.
-So the STM1 Frame rate per second = 19440 = 155.52 Mbps
-Noted that each one second contain 8000 STM1 Frame.
8000
MSOH : Multiplex Section Overhead
E1 : Order Wire at Regenerators
F1 : User Channel (64kb/s)
B2 : Bit Interleave Parity for Multiplex Section (BIP-24)
K1,K2 : Automatic Protection Switching (APS)
MS-AIS, MS-RDI
S1 : Synchronization Status
X : Reserved for national use
A1
A1
A1
A2
A2
A2
J0
B1
D1
E1
F1
D2
D3
B2
B2
B2
K1
K2
E2
S1
M1
Z1
Z1
Z2
Z2
REI : Remote Error Indicator
RDI : Remote Defect Indicator
This bytes are very important and using in BER “bit error rate” calculation
Guide to SDH
A1, A2 : Frame alignment signal
This is a unique identifier indicating start point of STM frame. It is using for Frame synchronization. Unscrambled. (A1 :11110110 A2 : 00101000)
J0 : Regenerator section trace
This byte used for the confirmation of correct regenerator section connection. Unscrambled(C1:Former recommendation)
B1 : Bit Interleaved Parity - 8
This is an 8 bits error check code using even parity coding. It allows each regenerator section to monitor and reset this byte. The BIP-8 is computed over all bits of the previous STM-N frame after scrambling and is placed in byte B1 before scrambling.
B2 : Bit Interleaved Parity -24
This is a 24 bits error check code using even parity coding. Each multiplex section monitor and reset this bytes. The BIP-24 is computed over all bits except for the first three rows of SOH and is placed in bytes B2 before scrambling.
E1 : Order wire for regenerator section
It is used to provided for order wire channels for voice communication. E1 is a part of RSOH and may be accessed at each regenerators. (64kb/s)
E2 : Order wire for multiplex section
E2 is a part of MSOH and may be accessed at each multiplexer. (64kb/s)
Guide to SDH
Guide to SDH2
Guide to SDH
Section Overhead (3)
F1 : User channel
This byte is reserved for user purposes (for example network operator) (64kb/s)
D1 - D3 : Data Communication Channel for Regenerator Section (DCCr)
This data channel passes the information between the regenerator sections and the network management center. This is to provide alarm monitoring, remote maintenance, reconfiguration, etc.(192kb/s)
D4 - D12 : Data Communication Channel for Multiplex Section (DCCm)
This is the data communication channel for the multiplex sections.(576kb/s)
K1, K2 : APS Channel (Automatic Protection Switching)
These are control bytes for any automatic protection switching that will be used on the network. The state of these bytes tells the network protection equipment which route to transmit on.
A part of K2 is also used to send the MS-RDI (Multiplex Section Remote Defect Indication/Formerly FERF, Far End Receive Failure) and MS-AIS (Multiplex Section Alarm Indication Signal).
S1 : Synchronization Status
This byte indicates quality of synchronization reference clock source used by the equipment.
M1 : Section Status Reporting
The result of BIT-24 (B2) is reported to its originating end by this byte as MS-REI (Multiplex Section Remote Error Indication) Formerly FEBE (Far End Block Error).
Z1, Z2 : Spare
Guide to SDH
I: Increment (positive frequency justification bits)
D: Decrement (negative frequency justification bits)
N: New Data Found (NDF) flags
• Enabled when at least 3 out of 4 bits match “1001”
• Disabled when at least 3 out of 4 bits match “0110”
• Invalid with other codes
at every multiplex section
1-If comparing is passed no errors.
2-If mismatch so this STM1 Frame is error Frame and called EB error Block.
As STM1 standard the duration for STM1 Frame is 125 micro second so each second passed from test contain 8000 STM1 frame.
This STM1 frame called Block.
So one second contain 8000 Blocks.
So if B1 or B2 record any error so this Block called error Block EB.
Guide to SDH
2-SES: Severely error second
3-BBE: Background block error
This is the number of EB that are not SES.
4-UAS: Unavailable second
This is the period the begins at the onset of ten consecutive SES events and this seconds are a part of this UAS time.
A new available time start at the onset of ten consecutive non SES events noted that this seconds are part of available time.
5-ESR: The number of seconds that contain any EB in available second/Total number of available seconds.
6-SESR: The number of second that is SES in the available second/Total number of available second.
7-BBER: The number of EB in the second the are not SES in available second/Total number of Blocks in available second except SES.
Performance definition (2)
Guide to SDH
2.048MHz clock signal or
data stream (from MUX equipment)
DMR CLK : Clock demodulated by the demodulator
from STM-1 data stream coming from the far-end radio station
INT CLK : Clock produced by the internal oscillator in the CLK module
Note; only for MST mode
Network Synchronization (2)
Guide to SDH
SET(Synchronous Equipment Timing Source)
Clock Type
Quality Level with S1 Byte Pattern
S1 byte is the signal to transmit QUALITY LEVEL of timing signal to all continually connected NEs.
The value of QUALITY LEVEL is transmitted by low 4-bit of MSOH S1 byte.
Network Synchronization (3)
2. Select the highest priority for the same
quality clock sources.
signal to be Q=6.
4. Backward direction S1 byte is set to Q=6
Network Synchronization (4)
Guide to SDH2
Guide to SDH
SSM: Synchronization status message part of S1 byte inform the neighbor NE about the status of the clock supply.
Switching Rules:
3-If link fail use Q=6 DNU independent of S1.
4-Make DNU Q=6 for the clock quality of backward signal
Network Synchronization (5)
Guide to SDH