Analyses of soft-state signaling protocols in GMPLS-Based WDM networks

摘要

Wavelength-routed Generalized Multi-Protocol Label Switching (GMPLS) networks use ResourcenreSerVation Protocol—Traffic Engineering (RSVP-TE) as signaling protocol to set up and tear downnlightpaths. RSVP-TE uses a soft-state control mechanism to manage lightpaths. In the soft-state controlnmechanism, each node sets a timer for each control state and resets the timer with refresh messages tonmaintain the state. When the timer expires due to losses of refresh messages, the control state is initializednand a reserved resource managed with the state is released. It has been considered that resource utilization ofnsoft-state protocols is inferior to that of hard-state protocols, since soft-state protocols may reserve resourcesnuntil control states are deleted due to timeout. Therefore, some extensions to promote the performance ofnsoft-state protocols, such as message retransmission, have been considered. In this paper, we analyze thenbehavior of GMPLS RSVP-TE and its variants with a Markov model and analyze the performance ofnRSVP-TE. From the results, we demonstrate that resource utilization of RSVP-TE can be equivalent to thatnof a hard-state protocol when the loss probability of signaling messages is low. We also investigate theneffectiveness of message retransmission and show that using message retransmission leads to poor resourcenutilization in some cases. Copyright © 2012 John Wiley & Sons, Ltd.