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Fault-Tolerant Fiber-Optic Network Using Wave-Division Multiplexing/ Demultiplexing Couplers

IP.com Disclosure Number: IPCOM000034595D
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 6 page(s) / 84K

Publishing Venue

IBM

Related People

Gopal, I: AUTHOR [+2]

Abstract

A technique is described whereby a fault-tolerant fiber-optic network, utilizes wave-division multiplexing/demultiplexing couplers to increase the availability of point-to-point wide-area networking. Transmission occurring from one node to another is full-duplex, over a single-mode fiber-optic link. The fault-tolerant fiber-optic network is a redundancy network which uses a single link so that each node consists of two identical switches. The two switches will transmit and receive over the same link through a different wavelength, utilizing wave-division multiplexing/demultiplexing couplers. Each side of the link contains a full-duplex link adapter (LA) where each adapter has a receiving side and a transmitting side. Each node utilizes several LAs.

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Fault-Tolerant Fiber-Optic Network Using Wave-Division Multiplexing/ Demultiplexing Couplers

A technique is described whereby a fault-tolerant fiber-optic network, utilizes wave-division multiplexing/demultiplexing couplers to increase the availability of point-to-point wide-area networking. Transmission occurring from one node to another is full-duplex, over a single-mode fiber-optic link. The fault-tolerant fiber-optic network is a redundancy network which uses a single link so that each node consists of two identical switches. The two switches will transmit and receive over the same link through a different wavelength, utilizing wave-division multiplexing/demultiplexing couplers. Each side of the link contains a full-duplex link adapter (LA) where each adapter has a receiving side and a transmitting side.

Each node utilizes several LAs. The transmission over the network is packetized where packets arriving at a receiving side of one of the node's LAs will be stored and then forwarded to a transmitting side of one of the node's LAs. The packet is forwarded to the transmitting side of a LA by way of a switching fiber-optic device.

(Image Omitted)

The fault-tolerant fiber-optic network architecture, as shown in Fig. 1, is constructed as follows: $ Duplication of Switch Fabrics - The fault-tolerant node

is constructed of two switching fabrics (switchA and

switchB), with each switch having the same number of

LAs. The switches are connected by way of a full-duplex

parallel port so that a packet can be forwarded from the

receiving side of a LA on one switch to the transmitting

side of a LA on the other switch. This connection is

important only in the active fault-olerant capability.

$ Two Wavelengths - The serial optical transmission of LAs

on switchA and switchB are by means of the wavelengths g1

(blue) and g2 (red), respectively.

$ Wave-Division Multiplexing/Demultiplexing (MUX/DMUX)

Coupler - The LAs on the two switches are paired. Each

pair is connected to an optical link leading to a

neighboring node via a wave-division (MUX/DMUX) coupler

placed on each side of the optical link. As a result,

the pair of LAs can use the optical link at the same

time. Note that the optical link is not duplicated.

$ End Node - The traffic of the network is generated via

the transmitting side of an end node, and the final

destination of every message is the receiving side of an

end node. The end node has two LAs, one which operates

with the blue wavelength g1, and the other with

the read wavelength, g2 . The end node can

send/receive packets to/from both LAs at the same time.

The wave-division (MUX/DMUX) coupler is a single-mode passive optical device. It can efficiently merge and split the transmission of two

1

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wavelengths. Fig. 2 illustrates the common configuration of the coupler for use in fiber-optic transmission. The bidirectional mode, in which one color is used for each direction, is shown in Fig. 2a. The unidirectional configurat...