Liaison statement
LS138 - Amendment 2 to G.872 OTN architecture

Q12/15 is in the process of updating G.872 the OTN architecture to reflect the
changes in the OTN rates and formats defined in G.709.  The most significant
additions are the inclusion of the ODU0 and the ODUflex, that allows a flexible
use of bandwidth.  The most significant change to the architecture is that we
now clarified that the ODU is modelled as a single layer network, with the bit
rate (of the client) represented as a parameter.  This evolution of OTN has
identified a number of significant new requirements from the perspective of the
control plane including: Support for the new ODU rates, ODU0, ODU4 and ODUflex
Support for the new server layer (OTU4) The ability to provide the information
required for path computation This includes the requirement to be able to
describe the maximum payload bandwidth that can be accommodated on a link as
well as the total available bandwidth. Maintain the independence between the
service rate (the rate of the ODU including ODUflex) and the OTU or higher
order ODU link that it is carried over. Provide the information that is
necessary to allow each node to compute the number of TS required and the
location of the stuff opportunities. We have attached the current draft of
G.872 amendment 2, we hope that you will find this useful in your work on the
extension of the GMPLS protocols to support OTN. Attachment:  WD10r5nc