The general communication channel (GCC) was defined by
G.709
ITU-T Recommendation G.709 ''Interfaces for the Optical Transport Network (OTN)'' describes a means of communicating data over an optical network. It is a standardized method for transparent transport of services over optical wavelengths in DWD ...
is an in-band side channel used to carry transmission management and signaling information within
optical transport network elements.
Two types of GCC are available:
* GCC0 – two bytes within
OTUk overhead. GCC0 is terminated at every 3R (re-shaping, re-timing, re-amplification) point and used to carry
GMPLS Generalized Multi-Protocol Label Switching (GMPLS) is a protocol suite extending MPLS to manage further classes of interfaces and switching technologies other than packet interfaces and switching, such as time-division multiplexing, layer-2 switchin ...
signaling protocol and/or management information.
* GCC1/2 – four bytes (each of two bytes) within
ODUk overhead. These bytes are used for client end-to-end information and shouldn't be touched by the OTN equipment.
In contrast to
SONET/SDH
Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized protocols that transfer multiple digital bit streams synchronously over optical fiber using lasers or highly coherent light from light-emitting diod ...
where the
data communication channel
In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted. ...
(DCC) has a constant data rate, GCC data rate depends on the OTN line rate. For example, GCC0 data rate in the case of OTU1 is ~333kbit/s, and for OTU2 its data rate is ~1.3 Mbit/s.
Computer networking
Optical Transport Network
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