E1 Primary Access and Multiplexing in PDH and SDH Networks

E1 Primary Access and Multiplexing

Multiplexing and Quantization

True or False: Multiframes are sent 500 per second in E1 primary access.

Plesiochronous multiplexers cause a loss of original formatting information.

CMI code requires greater bandwidth.

Question: What is the step size of a uniform quantizer with 2048 levels and a dynamic signal range of ±1V?

Answer: 0.977 mV

Question: How many quantization levels are in the second segment of a non-uniform quantizer using the A-law approach?

Answer: 16 levels

E1 Primary Access Characteristics

False Statement: In E1 primary access, the word alignment multiframe is transmitted every 15 frames.

True Statement: In E1 primary access, the word alignment multiframe is transmitted every 2 ms.

NFAS: Offers a speed alarm loss of synchronism of 4 kb/s.

E1 Frame Synchronization Byte: Transmits a Frame Alignment Signal (FAS) at 28 kb/s.

CRC and Network Characteristics

CRC Mechanism: Detects errors in an E1 multiframe.

E1 Quality Measurement: Plotting using the CRC error detection mechanism.

PDH Network Disadvantage: Requires transmission of management information.

PDH Network Advantage: Signals do not need to be generated with the same clock.

SDH and SONET Concepts

STM-1 Frame Pointers Function: Minimize synchronous network delay.

TUG-2 Definition: A group of tributary units used to transmit signals up to 6 Mb/s.

SDH Multiplexing Type: Time Division Multiplexing (TDM)

SONET Basic Signal Speed: 51.85 Mb/s

Regeneration Section Overhead: Covers 9 bytes of the first 3 rows of STM-1.

SDH Protection and Synchronization

SDH Protection Mechanisms: In bidirectional rings using two fibers, redundant capacity is booked on the active fibers.

False Statement: Positive pointer justification of a VC-4 containing a 140 Mb/s signal is used to justify speed differences in a 140 Mb/s plesiochronous signal.

True Statement: Jitter can affect the network signal within a container.

ADM Device Function: Allows extraction of synchronous tributaries from a higher-speed synchronous signal.

DXC Device Function: Allows switching between different channels connecting aggregates.

True Statement: Bandwidth protection for an always-active fiber is defined on another fiber.

False Statement: In an external synchronization method, nodes derive synchronization from frames received from other nodes.