Implicit Signaling over Stateless Networks
draft-mancuso-nsis-impl-sign-00

Abstract

This memo defines a mechanism for NSIS Signaling Layer Protocol (NSLP). The driving motivation is that some network domains, e.g. based on Differentiated Services data plane, might not explicit support a per-router and/or per-domain admission control rule. Hence, for such domains, explicit signaling is not a viable approach. To partially solve this issue, we suggest an admission control paradigm devised to provide ?Implicit Signaling? via data plane packet delivery operation. Implicit Signaling relies the decision to admit a new flow upon the successful and timely delivery, through the domain, of Probe packets independently generated by the NSIS initiator (NI). The key idea is to use failed receptions of Probes to discover, at the NI, that a congestion condition occurs in the network segment between NSIS initiator and NSIS Responder (NR), and to abort a reservation procedure. Since Implicit Signaling is not able to communicate per-flow traffic and QoS parameters, in principle it cannot exert a QoS control as tight as in the case of explicit mechanisms. However, it is important to notice that Implicit Signaling can indeed operate in a differentiated manner on the basis of traffic and QOS parameters, if i) Probes are marked according to the flow traffic and QoS requirements, ii) marked Probes experience a dropping behaviour according to their mark, and iii) Probe dropping is controlled according to measurements taken into the core routers.

Authors

Vincenzo Mancuso

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