Outline:• Comparison between PDH and SDH.• STM-N frame structure. • Multiplexing of of 140Mb/s, 34Mb/s and 2Mb/s signals into STM-N frame.• Common NE of SDH network.• SDH network structure and network protection mechanism.• Management, monitoring and alarms.

Comparison between PDH and SDHPoint of comparisonPDHSDH

Electrical & Optical

Interface

No universal

standard

universal

standard

multiplexing

method

complexsimple

Operation ,

administration

& Maintenance

Poor

administration

High

administration

CompatibilityIncompatible with other signals (ATM,

FDDI &DQDB)

compatible with other signals (ATM, FDDI

&DQDB)

BandwidthSave B.WHigh B.W

CoastLow coastHigh coast

Electrical interfacePDH

SDHElectrical interface

Multiplexing Method