()  Standards and recommendations I helped to develop

o Virtual Concatenation VCAT has been developped to provide more granularity in the transportable bandwidth of existing SDH multiplexes. In stead of VC-12, VC-3 or VC-4 with VCAT also the total payload of n x VC-12, n x VC-3 or n x VC-4 is available for the transport of client signals. VCAT signals are commonly referred to as VC-n-Xv.
The following standards bodies have Virtual Concatenation defined in the standards shown.

ITU-T

ITU-T Recommendations G.707 / Y.1322 and G.783 define VC-4-Xv, VC-3-Xv, VC-2-Xv, VC-12-Xv, VC-11-Xv for SDH.
For OTN Recommendation G.709 / Y.1331 defines ODUk-Xv and OPUk-Xv.

ETSI

ETSI standard EN 300 417-9-1 defines VC-4-Xv, VC-3-Xv, VC-2-Xv and VC-12-Xv with reference to the ITU-T recommendations.

ANSI

ANSI standard T1.105 defines STS-3c-Xv, STS-1-Xv, VT1.5-Xv



o Link Capacity Adjustment Scheme LCAS has been developped to add flexibility to Virtual Concatenation.
The LCAS methodology is defined in ITU-T recommendation G.7042 / Y.1305.
The LCAS technology is specified in G.707 / Y.1322. for SDH, G.709 / Y.1331. for OTN and G.7043 / Y.1343. for PDH.
o Generic Framing Procedure GFP is developped for mapping all kinds of client data units, e.g. Ethernet, MPLS, HDLC, Fiberchannel, ESCON, etc.
The GFP methodology is defined in ITU-T recommendation G.7041 / Y.1303.
GFP mapping is specified for SDH in ITU-T Recommendation G.707 / Y.1322. and for PDH in ITU-T Recommendation G.8040 / Y.1340.
o Together these methodologies, the enablers of Next Generation Networks, are referred to as DoS (Data over SDH/SONET) or EoS (Ethernet over SDH/SONET).

()  Books published:

o cover The ComSoc Guide to Next Generation Optical Transport: SDH/SONET/OTN
A comprehensive guide to SDH, SONET, and OTN linking the functional specification and the functional model.
o cover Next generation SDH/SONET. Evolution or Revolution?
Describes in detail Virtual Concatenation VCAT, Link Capacity Adjustment Scheme LCAS and Generic Framing Procedure GFP.
o cover Modeling the Optical Transport Network
Describes the functional modelling methodology that is used to define SDH, OTN, Ethernet, MPLS networks, and that can be used to model any layered network.
o cover Optical Networking Standards
A Comprehensive Guide for Professionals provides a single source reference of over a hundred standards and industry technical specifications for optical networks at all levels (I wrote a chapter).

()  Articles have appeared in:

o Lightwave magazine Dec 2001 issue. "Standards bring more flexibility to SONET/SDH".
o Optical Networks Magazine Jan/Feb issue 2003. "Standards Bring More Flexibility to Optical Transport".
o IEEE Communicatons Magazine May 2006 issue. "VCAT/LCAS in a Clamshell".

()  Tutorials

o SDH/SONET concatenation tutorial presented in ANSI standards meeting (contiguous concatenation CCAT, virtual concatenation VCAT and Link Capacity adjustment Scheme LCAS).
o Generric Framing Procedure GFP methodology presented in ANSI standards meeting.

()  LCAS examples

o Excercise 1. The creation of a three member Virtual Concatenation Group VCG supporting LCAS.
o Excercise 2. The planned addition of a member to the VCG of excercise 1.
o Excercise 3. The planned deletion of a member from the VCG of excercise 2.
o Excercise 4. The (temporary) removal of a member in the VCG of exercise 3 due to a network signal failure.
o Excercise 5. The restoration of a VCG after repair of the network problem.
o Excercise 6. The (temporary) removal of a member in the VCG of excercise 3 due to a network signal degradation.
All excercises are explained in much more detail in my book: Next generation SDH/SONET. Evolution or Revolution?

()  Related links

o Murton Consultancy & Design Ltd. SDH and Metro Ethernet Design.

More to come....

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