A comparison of in-band and out-of-band transport options for signaling

Signaling protocols for GMPLS networks have been standardized and are now being implemented. Most switch vendors allow for signaling messages to be carried over in-band signaling channels as well as through out-of-band networks. In this paper, we compare these two signaling transport options. In carrying out this analysis, we allow for both software-implemented signaling protocol processors, as is common in most off-the-shelf switches today, as well as hardware-accelerated signaling protocol engines. Our research project on hardware-accelerated signaling is in support of a service concept in which dynamically provisioned high-speed end-to-end circuits are used for single file transfers. In this application, signaling message loads will be extremely high since call holding times will be short. For such a usage, we need a signaling transport solution that minimizes message transfer times. Therefore this question of in-band versus out-of-band signaling transport is relevant to our research. Our analysis shows that with hardware-accelerated signaling engines, in-band signaling is the better option, while in a network with only software signaling processors, the out-of-band solution is better.