Optical switch and protocols for use therewith
First Claim
1. A switching node, comprising:
- an optical switch fabric for switching optical signals arriving on a plurality of input optical fiber segments over to a plurality of output optical fiber segments in accordance with mapping instructions;
wavelength conversion means connected to the optical switch fabric, for modifying the wavelengths occupied by incoming or switched optical signals in accordance with conversion commands; and
a control unit connected to the optical switch fabric and to the wavelength conversion means, for exchanging control information with other switching nodes using a network layer protocol and generating said mapping instructions and said conversion commands based on said control information.
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Abstract
A method of establishing a data connection between terminal switching nodes in a network and switching nodes for implementing the method. The method involves switching nodes participating in a network layer wavelength routing (WR) protocol to determine the next hop switching node for every possible combination of terminal nodes based on the network topology. The method also involves the switching nodes participating in a network layer wavelength distribution (WD) once the data connection is to be established. The WR protocol determines the path used through the network, while the WD protocol assigns wavelengths on each link between switching nodes. The wavelengths may be different on different optical links. The switching nodes include wavelength converters with an optical switch or optoelectronic converters with a digital electronic switch. A digital electronic switch can also provide signal reformatting. Advantages of using potentially different wavelengths along various segments of a single end-to-end connection yields increased wavelength efficiency.
35 Citations
29 Claims
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1. A switching node, comprising:
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an optical switch fabric for switching optical signals arriving on a plurality of input optical fiber segments over to a plurality of output optical fiber segments in accordance with mapping instructions;
wavelength conversion means connected to the optical switch fabric, for modifying the wavelengths occupied by incoming or switched optical signals in accordance with conversion commands; and
a control unit connected to the optical switch fabric and to the wavelength conversion means, for exchanging control information with other switching nodes using a network layer protocol and generating said mapping instructions and said conversion commands based on said control information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A switching node, comprising:
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a first plurality of optoelectronic converters, for converting input optical signals occupying respective wavelengths into electronic signals;
a second plurality of optoelectronic converters, for converting output electronic signals into output optical signals occupying respective wavelengths;
a digital switch fabric connected to the optoelectronic converters, for switching the input electronic signals over to the output electronic signals in accordance with mapping instructions; and
a control unit connected to the digital switch fabric and to the optoelectronic converters, for exchanging control information with other switching nodes using a network layer protocol and generating said mapping instructions based on said control information. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A method of establishing a data connection between first and second terminal switching nodes in an optical network, the network comprising said terminal switching nodes and a plurality of other switching nodes interconnected by multi-wavelength optical links, the method comprising:
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identifying a path comprising a set of links and wavelengths for transporting data between the first and second terminal switching nodes via zero or more intermediate switching nodes; and
at each intermediate switching node connected to a respective ingress link and a respective egress link in the identified path, switching the optical signals arriving on the respective ingress link over to the respective egress link and performing wavelength conversion if the wavelengths occupied on the respective ingress and egress links are different. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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29. A wavelength distribution protocol for enabling the establishment of a data connection between a first terminal switching node and a second terminal switching node via zero or more intermediate switching nodes along a path in a network, wherein an initial CONNECTION_REQUEST message is sent to the first terminal switching node upon initially requesting said data connection, the protocol comprising, at each current switching node connected in said path between a previous switching node and/or a next switching node by respective optical links:
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receiving messages from the previous or next switching node;
if the message is a CONNECTION_REQUEST message, then;
if the current switching node is not the first terminal switching node, identifying and storing an available wavelength on the link between the current and previous switching nodes; and
if the current switching node is the second terminal switching node, establishing a connection using the available wavelength and sending a CONNECTION_CONFIRM message to the previous switching node, otherwise forwarding the CONNECTION_REQUEST message to the next switching node; and
if the message is a CONNECTION_CONFIRM message, then;
establishing a connection using the previously stored available wavelength; and
if the current switching node is not the first terminal switching node, sending a CONNECTION_CONFIRM message to the previous switching node.
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Specification