Benefits of Node Architecture Flexibility and Hitless Re-Grooming in Transport Networks

This paper proposes dimensioning models for transport network nodes taking into consideration the multiplexing/grooming architecture. The models are suitable for multi-period planning and assume node architectures with different levels of flexibility. Fixed architectures are based on muxponder modules whereas flexible architectures comprise an electrical cross connect (EXC). Within the flexible architectures, non-blocking EXC and partial non-blocking EXCs architectures are considered. Importantly, the models also support hitless re-grooming in flexible architectures. Using the developed models, we analyze the impact of node architecture flexibility in the number of line interfaces required, and assess the potential savings attained by exploiting hitless re-grooming. Results show that enhanced flexibility produces more savings when the client traffic bit rate is much smaller than the line bit rate. Moreover, hitless traffic re-grooming can assist in mitigating the impact of flexibility limitations that arise when deploying smaller sized EXCs.