AimValley proposes Transparent SDH/SONET over Packet

Technical design and consultancy firm AimValley, working in collaboration with Alcatel-Lucent (Euronext Paris and NYSE: ALU), has published an International Engineering Task Force (IETF) draft standard that describes Transparent SDH/SONET over Packet (TSoP) technology.

The essence of the TSoP method is that an STM-N or OC-N client signal is transported completely transparently in a pseudowire (PW) over a packet-switched network (PSN). This means that the bits that are input on one edge of the PSN are exactly the same as the bits that are output on the other edge. The key property of the TSoP method is that it transports the SDH/SONET client signal in its entirety through the PW, i.e., no use is made of any specific characteristic of the SONET/SDH signal format other than its bit rate.

Although circuit-emulation techniques are routinely deployed in networks, there was, until now, no standardized method for the emulation of complete STM-N or OC-N circuits in a transparent manner over MPLS and Ethernet packet networks. The single existing standard in this area (IETF RFC 4842) only specifies the transport of the virtual container(s) inside the STM-N/OC-N signal. This approach effectively blocks transport of the embedded channels for network management, automatic protection switching, and a number of other maintenance functions in the STM-N/OC-N overhead that are of key importance to an operator, Aim Valley asserts.

Alcatel Lucent and AimValley have taken the initiative to close this gap by publishing an IETF draft standard that describes such a better method in a document provisionally titled: draft-manhoudt-pwe3-tsop. This circuit-emulation method has been applied in the TSoP Smart SFP module that was jointly developed by AimValley and OE Solutions (see "Smart SFP first offering from OE Solutions, AimValley collaboration").

"The TSoP Smart SFP processes the STM-N/OC-N signal fully transparent, maintaining payload structure, protection protocols and synchronization end-to-end; this simplifies the configuration and service turn-up of STM N/OC N connections across a packet network," said Pieter de Boer, managing director at AimValley. "The integration of TSoP into an SFP greatly reduces system and network complexity, and offers lower carbon footprint while generating capex and opex savings."

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