Digital Transmission Hierarchies and Networks is one of the very few books dealing with all the three generations of digital multiplexing hierarchies, namely plesiochronous digital hierarchy (PDH), synchronous digital hierarchy (SDH) and optical transport hierarchy (OTH) in a full-fledged manner. Perhaps it is the only book demystifying the complex processes of justification and frame formation in PDH, pointer operations, concatenation and synchronisation in SDH and management overhead structures for digital wrapper and optical channel layers in OTH. The book covers the reliability and survivability aspects of the networks, applications like Ethernet, multi-protocol label switching (MPLS), VoIP over SDH, multi-protocol wavelength switching (MPWS), gigabit MPLS over OTN, passive optical network (PON), GPON and next generation switching network (NGN).The depth of coverage of topics in the book offers a thorough understanding of digital transmission hierarchies, which students of communications engineering as well as practising engineers and professionals dealing with OFC projects will find useful for the insight it provides on both the practical and the conceptual aspects of networking.