Multi-fabric shelf for a transport network
A network element of a transport network has three fabrics housed within a single shelf of a telco rack, namely a packet fabric, an electrical fabric and an optical fabric. The shelf also includes inter-fabric circuitry, to bridge between the fabrics, e.g. packet-electrical and/or electrical-optical and/or packet-optical. The inter-fabric circuitries switchably transmit packets across fabrics in intermediate nodes of the transport network. The single shelf of some embodiments has a wall (“midplane”) between a rear region that holds the three fabrics and a front region that holds inter-fabric circuitry, and external interfaces to optical trunks and/or packet services and/or optical tributaries.
1. A network element for use in a communication network, the network element comprising:
a shelf comprising a first volume, a second volume and a wall between the first volume and the second volume;
a plurality of fabrics located within the first volume of said shelf, at least one fabric in the plurality of fabrics comprising a crossbar, the plurality of fabrics comprising a first fabric, a second fabric and a third fabric;
a plurality of external interfaces located within the second volume of said shelf, the plurality of external interfaces comprising at least a first interface coupled to the first fabric, and a third interface coupled to the third fabric;
a plurality of inter-fabric circuitry located within the second volume of said shelf, the plurality of inter-fabric circuitry comprising a first-second inter-fabric circuitry and a second-third inter-fabric circuitry;
wherein the first-second inter-fabric circuitry is coupled to each of the first fabric and the second fabric;
wherein the second-third inter-fabric circuitry is coupled each of the second fabric and the third fabric;
wherein the first interface is coupled to the third interface via the first-second inter-fabric circuitry, the second fabric and the second-third inter-fabric circuitry;
wherein said third fabric and said second fabric are comprised in an electrical fabric module mounted in the first volume;
wherein said first fabric is comprised in an optical fabric module mounted parallel the electrical fabric module in the first volume;
wherein the first-second inter-fabric circuitry is comprised in a first inter-fabric card within the second volume, the first inter-fabric card being mounted perpendicular to said modules;
wherein the second-third inter-fabric circuitry is comprised in a second inter-fabric card within the second volume, the second inter-fabric card being mounted parallel to the first inter-fabric card and perpendicular to said modules; and
wherein the network element further comprises a plurality of orthogonal connectors mounted on the wall, the plurality of orthogonal connectors electrically connecting the electrical fabric module to each of said first inter-fabric card and said second inter-fabric card.
2. The network element of claim 1 wherein:
the third interface comprises an ingress path and an egress path;
the ingress path comprising:
an ingress tap;
a first optical attenuator coupled to the ingress tap;
an optical amplifier coupled to the first optical attenuator; and
an optical splitter coupled to the optical amplifier, the optical splitter being further coupled to an input of the first fabric;
the egress path comprising:
a wavelength selective switch;
an amplifier coupled to the wavelength selective switch;
a second optical attenuator coupled to the wavelength selective switch;
an egress tap coupled to the second optical attenuator; and
a wavelength division multiplexer coupled to the egress tap;
said third fabric and a plurality of all-optical line cards including said third interface are comprised in an all-optical cross-connect.
3. The network element of claim 1 wherein:
said second fabric comprises said crossbar; and
said second fabric and a group of second interfaces are comprised in an analog electrical cross-connect.
4. The network element of claim 1 wherein:
said crossbar is time division multiplexed.
5. The network element of claim 1 wherein:
said first fabric comprises a switch fabric, the first interface comprises a traffic manager and a network processor, and the first fabric and the first interface are comprised in a packet switch; and
said third fabric and a plurality of all-optical line cards including said third interface are comprised in an all-optical cross-connect.
6. The network element of claim 1 wherein the first inter-fabric card comprises:
a framer coupled to the second-third inter-fabric circuitry to receive therefrom an electrical signal comprising data recovered from a selected wavelength received by the third interface, the framer being electrically coupled by an orthogonal connector in the wall to the second fabric to transmit thereto a framed version of said electrical signal.
7. The network element of claim 6 further comprising in an optical path between the third fabric and the second-third inter-fabric circuitry:
an optical switch optically coupled to the third interface to receive therefrom a plurality of light signals;
a tuneable optical filter optically coupled to the optical switch to receive therefrom one light signal selected from among the plurality of light signals;
a tuneable optical transceiver optically coupled to the tuneable optical filter to receive therefrom a wavelength selected from among a plurality of wavelengths within said selected one light signal;
wherein said framer is coupled to the tuneable optical transceiver.
8. The network element of claim 1 wherein the third interface comprises an ingress path, said ingress path comprising:
an ingress tap;
an optical attenuator coupled to the ingress tap;
an optical amplifier coupled to the optical attenuator; and
an optical splitter coupled to the optical amplifier, the optical splitter being further coupled to an input of the first fabric.
9. The network element of claim 1 wherein the third interface comprises an egress path, the egress path comprising:
a wavelength selective switch;
an amplifier coupled to the wavelength selective switch;
an optical attenuator coupled to the wavelength selective switch;
an egress tap coupled to the optical attenuator; and
a wavelength division multiplexer coupled to the egress tap.
10. The network element of claim 1 wherein:
said second fabric comprises said crossbar.
11. The network element of claim 1 wherein:
said second fabric and a group of second interfaces are comprised in an analog electrical cross-connect.
12. The network element of claim 1 wherein:
the first interface comprises a traffic manager and a network processor.
13. The network element of claim 1 wherein:
said first fabric comprises a switch fabric.
14. The network element of claim 1 wherein:
the first fabric and the first interface are comprised in a packet switch.
15. The network element of claim 1 wherein:
at least said third fabric is comprised in an all-optical cross-connect.
16. The network element of claim 1 wherein:
a plurality of all-optical line cards including said third interface are comprised in an all-optical cross-connect.
17. The network element of claim 1 wherein:
said third fabric and a plurality of all-optical line cards including said third interface are comprised in an all-optical cross-connect in the network element.
18. The network element of claim 1 wherein:
the first inter-fabric card comprises a framer coupled to the second-third inter-fabric circuitry.
19. The network element of claim 1 further comprising in an optical path between the third fabric and the second-third inter-fabric circuitry:
an optical switch optically coupled to the third interface.
20. The network element of claim 1 further comprising in an optical path between the third fabric and the second-third inter-fabric circuitry:
a tuneable optical transceiver to receive a wavelength selected from among a plurality of wavelengths within a light signal in said optical path.