FRAMED FLOWS OVER PACKET-SWITCHED FABRICS

• US 20110255552A1
• Filed: 04/20/2010
• Published: 10/20/2011
• Est. Priority Date: 04/20/2010
• Status: Active Grant

• Current Assignee: Microsemi Storage Solutions, Inc (Microchip Technology Incorporated)
• Original Assignee: Vitesse Semiconductor Corp (Microchip Technology Incorporated)
• Inventors: Ellegard, Lars
• Granted Patent: US 8,363,670 B2
• Time in Patent Office: Days
• US Class Current: 370/419
• CPC Class Codes: H04J 2203/0007 Space switch details
• CPC Class Codes: H04J 3/1652 Optical Transport Network [OTN]
• CPC Class Codes: H04L 49/10 characterised by the switching fabric construction

Abstract

A networking device and a method provide switching of framed signals using a packet switch fabric. Framed input signals, which may be OTN signals, are received and converted to packets. The conversion includes striping the received signal into virtual lanes and segmenting the lanes into packets. The packets are switched through the packet switch fabric, which may be an Ethernet switch, and then converted to framed output signals. The conversion includes reassembly of the packets into virtual lanes. The reassembled virtual lanes are frame aligned, deskewed, and combined to produce the framed output signals.

Claims

1. A networking device for switching framed flows with packet-based switching, comprising:

a plurality of ingress converters, each of the plurality of ingress converters configured to receive a framed input signal and to convert the framed input signal into packets to be placed in a plurality of virtual lanes;

a packet switching fabric coupled to the plurality of ingress converters to receive the packets in the plurality of virtual lanes on a plurality of input ports and configured to switch the packets to a plurality of output ports; and

a plurality of egress converters, each of the plurality of egress converters coupled to the packet switching fabric to receive at least some of the packets from the output ports of the packet switching fabric and configured to supply a framed output signal converted from the received packets.

2. The networking device of claim 1, wherein the framed input signals are ODU signals and the framed output signals are ODU signals.

3. The networking device of claim 1, wherein the packet switching fabric switches Ethernet packets.

4. The networking device of claim 1, wherein each of the plurality of ingress converters comprises:

a striping module configured to inverse multiplex the framed input signal into a plurality of virtual lanes; and

a plurality of segmentation modules, each of the plurality of segmentation modules receiving one of the plurality of virtual lanes and segmenting the data in the received virtual lane into a sequence of packets.

5. The networking device of claim 1, wherein the striping module assigns data from the framed input signal to the virtual lanes based on a frame alignment signal in the framed input signal.

6. The networking device of claim 5, wherein the striping module assigns data from the framed input signal to the virtual lanes additionally based on a multiframe alignment signal in the framed input signal.

7. The networking device of claim 4, wherein the striping module is further configured to add padding information to the framed input signal.

8. The networking device of claim 1, wherein each of the plurality of egress converters comprises:

a plurality of reassembly modules, each of the plurality of reassembly modules configured to receive packets from the packet switching fabric associated with one of the plurality of virtual lanes and to produce a reassembled virtual lane assembled from the data in the received packets, where the received packets include an identifier of the virtual lane created in a corresponding ingress converter;

a plurality of frame alignment modules, each of the plurality of frame alignment modules configured to receive the reassembled virtual lane from one of the plurality of reassembly modules and find a frame alignment in reassembled virtual lane;

a deskew module coupled to the plurality of frame alignment modules and configured to time-align the reassembled virtual lanes; and

a combing module coupled to the deskew module and configured to combine the reassembled virtual lanes for transmission as a framed output signal.

9. The networking device of claim 1, wherein each of the plurality of egress converters comprises:

a plurality of reassembly modules, each of the plurality of reassembly modules configured to receive packets from the packet switching fabric associated with one of the plurality of virtual lanes and to produce a reassembled virtual lane assembled from the data in the received packets;

a plurality of frame alignment modules, each of the plurality of frame alignment modules configured to receive the reassembled virtual lane from one of the plurality of reassembly modules and find a frame alignment in reassembled virtual lane;

a deskew module coupled to the plurality of frame alignment modules and configured to time-align the reassembled virtual lanes; and

a lane reordering module coupled to the deskew module and configured to order the reassembled virtual lanes and combine the recorded reassembled virtual lanes for transmission as a framed output signal.

10. The networking device of claim 1, wherein each of the ingress converters is further configured to change the number of virtual lanes in the plurality of virtual lanes while converting the framed input signal.

11. A method of switching framed signals with a packet-based switch, the method comprising:

receiving a plurality of framed input signals;

converting each of the plurality of framed input signals to packets logically grouped in virtual lanes;

switching the packets converted from the plurality of framed input signals from input ports of a packet switch fabric to output ports of the packet switch fabric;

converting the packets from the output ports of the packet switch fabric to framed output signals; and

transmitting the framed output signals.

12. The method of claim 11, wherein converting each of the plurality of framed input signals to packets logically grouped in virtual lanes comprises:

inverse multiplexing the framed input signal into a plurality of virtual lanes; and

segmenting each of the plurality of virtual lanes into a sequence of packets.

13. The method of claim 11, wherein converting the packets from the output ports of the packet switch fabric to framed output signals:

reassembling the packets from the output ports of the packet switch fabric associated with one of the virtual lanes to produce a reassembled virtual lane assembled from the data in the received packets;

determining frame alignment in each of the reassembled virtual lane

deskewing the reassembled virtual lanes using the determined frame alignments; and

combining the deskewed reassembled virtual lanes to produce the framed output signals.

14. The method of claim 13, further comprising reordering the deskewed reassembled virtual lanes to correspond to an ordering used in converting each of the plurality of framed input signals to packets logically grouped in virtual lanes.

15. The method of claim 11, further comprising changing a number of virtual lanes the packets are logically grouped in while converting one of the plurality of framed input signals to packets logically grouped in virtual lanes.