Granted Patent B2

US 8,750,706 · App. 13/047,411 · Granted Jun 10, 2014

Inventors: David Boertjes (Nepean, CA); Gerard Swinkels (Ottawa, CA); Serge Asselin (Kanata, CA); Ryan Amenta (Carleton Place, CA)

Assignee: Ciena Corporation

Abstract

Claims (35)

1. A method of controlling a communications network including an electronic traffic routing layer and an optical transport layer, the method comprising:

routers of the electronic traffic routing layer detecting a connection failure, and electronically switching traffic flows affected by the connection failure to a protection path in the electronic traffic routing layer;

when the detected connection failure is due to a span failure in the optical transport layer, a controller identifying EO interfaces terminating an optical channel affected by the span failure, reconfiguring directionally independent access (DIA) nodes connected to the failed span, and setting up a new optical channel through the optical transport layer between the identified EO interfaces; and

the routers of the electronic traffic routing layer recognising the new optical channel as a restored connection in the electronic traffic routing layer; and electronically switching traffic flows from the protection path to the restored connection.

2. The method as claimed in claim 1 , wherein the protection path in the electronic traffic routing layer is a predetermined protection path.

3. The method as claimed in claim 1 , wherein the protection path in the electronic traffic routing layer is computed following detection of the connection failure.

4. The method as claimed in claim 1 , wherein setting up the new optical channel through the optical transport layer comprises computing a route for the new optical channel that minimizes latency between the identified EO interfaces.

5. The method as claimed in claim 1 , wherein setting up the new optical channel through the optical transport layer comprises:

computing two or more candidate routes through the optical transport layer between the identified EO interfaces;

computing a respective latency for each candidate route;

selecting the candidate route having a computed latency that most closely matches that of the optical channel affected by the span failure; and

setting up the new channel using the selected candidate route.

6. The method as claimed in claim 1 , wherein a route for the new optical channel differs from that of the protection path in the electronic traffic routing layer.

7. An optical communications network comprising:

a plurality of network elements, each network element comprising:

an electronic router coupled to a set of client access ports and a plurality of I/O ports, the electronic router for forwarding traffic between the set of client access ports and the plurality of I/O ports;

a respective EO interface coupled to each one of the plurality of I/O ports, each EO interface terminating a respective optical channel; and

a directionally independent access (DIA) node for selectively routing each optical channel between its respective EO interface and a selected one of at least two optical fiber links of the optical communications network, the (DIA) node comprising:

a first wavelength selective switch (WSS) having at least one port optically connected to the EO interfaces; and

a respective branch WSS optically connected to each optical fiber link and the first WSS;

the first WSS configured to selectively route optical channels between the EO interfaces and a selected branch WSS, and each branch WSS configured to selectively route optical channels between its respective optical fiber link and the first WSS;

each electronic router being configured to:

detect a connection failure, and electronically switch traffic flows affected by the connection failure to a predetermined protection path; and

detect restoration of a previously failed connection, and electronically switch traffic flows affected by the connection failure from the predetermined protection path to the restored connection;

a controller responsive to a span failure affecting an optical fiber link to:

identify EO interfaces terminating an optical channel affected by the span failure;

reconfigure directionally independent access (DIA) nodes connected to the failed span, and

set up a new optical channel through the optical transport layer between the identified EO interfaces.

8. The network as claimed in claim 7 , wherein the controller is further configured to compute a route for the new optical channel that minimizes latency between the identified EO interfaces.

9. The network as claimed in claim 7 , wherein the controller is further configured to:

compute two or more candidate routes through the optical transport layer between the identified EO interfaces;

estimate a respective latency for each candidate route;

select the candidate route having a lowest computed latency; and

set up the new channel using the selected route.

10. The network as claimed in claim 7 , wherein each EO interface is tuneable to a desired optical wavelength channel.

Assignments (8)

Continuity (2)