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Method to Economically Introduce Optical Bypassing

IP.com Disclosure Number: IPCOM000018866D
Original Publication Date: 2003-Sep-25
Included in the Prior Art Database: 2003-Sep-25
Document File: 2 page(s) / 345K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

Widely, optical bypassing is critical to efficiently mesh switching or routing equipment. The cost and performance analysis of the communication network that have been designed to include optical bypassing has mostly been performed under the assumption that a certain volume of communications traffic has to be transported by the network from the beginning. A gradual growth of traffic volume and the associated need for a backlog investment were not calculated. The network could also develop differently to the planned traffic growth projection created a "stranded investment". Optical bypassing in fiber optic networking are introduced by means of creating a wavelength switching network layer or of statically wire pre-planned optical bypasses. The first method utilizes optical cross-connections (OXC) which are either implemented all-optically (traffic bearing signals remain in the optical domain at all times - OOO) or optical-electronic and consecutive electronic optical conversion (OEO). The different OXC's reside at the network nodes and are interconnected by optical transmission links which are implemented e.g. as Dense Wavelength Division Muliplex (DWDM). The signals of the so called lightpaths enter into the wavelength switching network layer at an ingress node and are routed by line systems which are connected by intermediate nodes until the egress node where the signals drop out of the wavelength switching network layer. At this transmission, the traffic bearing signals are only crossing the OXC. They will be not funneled through lower order switching or routing network equipment that processes the signals at a granularity below the line bit rate. This is referred to as optical bypassing. In a broader sense, the OXC includes a remotely configurable Optical Add-Dropp Multiplexer (OADM) which is capable of optical bypassing. With this method of OXC, the lightpaths and optical bypasses can be created and deleted arbitrarily to achieve maximum network efficiency. It supplies an agility of a switched wavelength routing network layer for a fast lightpath restoration in case of link or node failures. But the disadvantages of this method are the high costs of OXC by means of network additions, the reduced performance of the connected line systems (with reference to OXC - OOO) due to detrimental effects to the optical signal and eventually the economies of integrating long haul optical interfaces into client equipment of the wavelength switching network layer.

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Method to Economically Introduce Optical Bypassing

Idea: Hubert A. Jaeger, US-Reston; Bjoern Kracker, US-Reston; Lance Hassan, US-Reston;

Stephan Rettenberger, US-Boca Raton

Widely, optical bypassing is critical to efficiently mesh switching or routing equipment. The cost and performance analysis of the communication network that have been designed to include optical bypassing has mostly been performed under the assumption that a certain volume of communications traffic has to be transported by the network from the beginning. A gradual growth of traffic volume and the associated need for a backlog investment were not calculated. The network could also develop differently to the planned traffic growth projection created a "stranded investment". Optical bypassing in fiber optic networking are introduced by means of creating a wavelength switching network layer or of statically wire pre-planned optical bypasses.

The first method utilizes optical cross-connections (OXC) which are either implemented all-optically (traffic bearing signals remain in the optical domain at all times - OOO) or optical-electronic and consecutive electronic optical conversion (OEO). The different OXC's reside at the network nodes and are interconnected by optical transmission links which are implemented e.g. as Dense Wavelength Division Muliplex (DWDM). The signals of the so called lightpaths enter into the wavelength switching network layer at an ingress node and are routed by line systems which are connected by intermediate nodes until the egress node where the signals drop out of the wavelength switching network layer. At this transmission, the traffic bearing signals are only crossing the OXC. They will be not funneled through lower order switching or routing network equipment that processes the signals at a granularity below the line bit rate. This is referred to as optical bypassing. In a broader sense, the OXC includes a remotely configurable Optical Add-Dropp Multiplexer (OADM) which is capable of optical bypassing. With this method of OXC, the lightpaths and optical bypasses can be created and deleted arbitrarily to achieve maximum network efficiency. It supplies an agility of a switched wavelength routing network layer for a fast lightpath restoration in case of link or node failures. But the disadvantages of this method are the high costs of OXC by means of network additions, the reduced performance of the connected line systems (with reference to OXC - OOO) due to detrimental effects to the optical signal and eventually the economies of integrating long haul optical interfaces into client equipment of the wavelength switching network layer.

The second method doesn't provide for a re-configurable wavelength routing layer. Optical bypasses are introduced at pre-planned routes from the beginning. At the intermediate nodes, the ports of the incomin...