Survivable Multipath Traffic Grooming in Telecom Mesh Networks With Inverse Multiplexing

Abstract

Abstract—We investigate the survivable traffic grooming prob-lem with inverse multiplexing in next-generation SONET/SDH networks employing wavelength-division multiplexing (WDM). With support of virtual concatenation (VCAT), a connection of any bandwidth can be provisioned as several sub-connections (i.e., inverse-multiplexed) over diverse paths. How to efficiently protect and groom these low-speed sub-connections onto high-capacity wavelength channel, considering the typical constraints, is an important and interesting problem. We propose and investigate the characteristics of survivable multipath traffic grooming with protection-at-connection (MP-PAC) level and protection-at-lightpath (MP-PAL) level for grooming a connection request with shared protection, subject to the constraints of inverse-multiplexing factor (IMF), differential-delay constraint (DDC), and grooming ports. Since a special case of this problem (IMF = 1, DDC = ∞) is NP-complete, we propose effective heuristics with a novel analytical model. Our results indicate that (1) the network performance can be notably improved by exploiting the inverse-multiplexing capability, (2) tight constraints have negative impact on performance, (3) protection-at-lightpath level achieves better performance when the number of grooming ports is moderate or small, and (4) protection-at-connection level outperforms in most cases in multipath provisioning when the constraints are not too tight. Index Terms—Telecom mesh networks, wavelength-division multiplexing (WDM), virtual concatenation (VCAT), multipath provisioning, survivable traffic grooming, inverse multiplexing. I.