Preliminary Definitions

Please refer to Table 1 for a description of the terminology. Before we delve into estimating the delay for each scheme, we shall define the delay for a path. If $d_{DCN}(x)$ and $d_{OTN}(x)$ is the delay incurred due to a message travelling $x$ hops through the DCN and the OTN respectively, then:

$$d_{DCN}(x) = x\cdot (t_{proc} + t_{prop}) + t_{proc}$$ (1)

$$d_{OTN}(x) = \frac{b_{len}}{c}\cdot x$$ (2)

We shall follow the discussion in [7] and calculate the restoration delay as contributed by each phase of restoration. Hence:

$$t_{restore} = t_{detect} + t_{FIS} + t_{setup} + t_{switch}$$ (3)

Figure 1: The RSVP/Backup Tunnel serial restoration scheme.