PATENT DOCUMENT

Publication Number: US-8966134-B2
Application Number: US-201213403182-A
Country: US
Kind Code: B2

Title: Cross-over and bypass configurations for high-speed data transmission

Abstract:
Circuits, methods, and apparatus that may improve networking techniques for transferring data among various electronic devices. One example may provide sharing data among various devices by daisy-chaining devices together. That is, several devices may be connected to each other through a series of cables to form a chain of devices. In this physical configuration, data may be shared among multiple devices using a series of single-hop virtual tunnels. Alternatively, a number of tunnels may be formed by a host device, each having a target device in the daisy chain. Each tunnel may originate at the host device and terminate at their target device. Each tunnel may bypass devices between the host device and the tunnel&#39;s target device. These two techniques may also be combined. Another example may provide a method of simplifying the routing of high-speed data signals through a network topology.

Claims:
What is claimed is: 
     
       1. A method of transferring data among a plurality of electronic devices comprising:
 forming a first tunnel in a host device, the first tunnel for conveying data for a first electronic device and a second electronic device; 
 using a first physical cable as a physical path for the first tunnel to transmit the data for the first electronic device and the second electronic device from the host device to the first electronic device; 
 receiving the data for the first electronic device and the second electronic device at the first electronic device using a first switching circuit in the first electronic device; 
 passing the data for the first electronic device and the second electronic device from the first switching circuit to a second switching circuit in the first electronic device; 
 providing the data for the first electronic device to circuitry in the first electronic device using the second switching circuit; 
 forming a second tunnel in the first electronic device using the second switching circuit, the second tunnel for conveying data for the second electronic device; 
 passing the data for the second electronic device from the second switching circuit to the first switching circuit; 
 using a second physical cable as a path for the second tunnel to transmit the data for the second electronic device from the first switching circuit in the first electronic device to the second electronic device; and 
 receiving the data for the second electronic device at the second electronic device. 
 
     
     
       2. The method of  claim 1  wherein the data for the first electronic device and the second electronic device is PCIe data. 
     
     
       3. The method of  claim 2  wherein the first tunnel and the second tunnel are formed by a first PCIe adapter and a second PCIe adapter, each PCIe adapter associated with a switching circuit. 
     
     
       4. The method of  claim 3  wherein the host device is a laptop device and the first electronic device is a hard drive. 
     
     
       5. The method of  claim 3  wherein the first tunnel and the second tunnel are Thunderbolt compliant. 
     
     
       6. The method of  claim 1  where the first switching circuit is a Thunderbolt switch and the second switching circuit is a PCIe switch. 
     
     
       7. A method of transferring data among a plurality of electronic devices comprising:
 forming a first tunnel in a host device, the first tunnel for conveying data for a first electronic device; 
 forming a second tunnel in the host device, the second tunnel for conveying data for a second electronic device; 
 using a first physical cable as a physical path for the first tunnel to transmit the data for the first electronic device from the host device to the first electronic device; 
 using the first physical cable as a physical path for the second tunnel to transmit the data for the second electronic device from the host device to the first electronic device; 
 receiving the data for the first electronic device at the first electronic device; 
 bypassing at least a portion of the first electronic device with the second tunnel; 
 using a second physical cable as a physical path for the second tunnel to transmit the data for the second electronic device from the first electronic device to the second electronic device; and 
 receiving the data for the second electronic device at the second electronic device, 
 wherein receiving the data for the first electronic device at the first electronic device and bypassing at least a portion of the first electronic device with the second tunnel comprises: 
 receiving the data for the first electronic device and the data for the second electronic device at a first switching circuit in the first electronic device; 
 providing the data for the first electronic device to a second switching circuit in the first electronic device using the first switching circuit; 
 providing the data for the first electronic device to circuitry in the first electronic device using the second switching circuit; and 
 providing the data for the second electronic circuit to the second cable using the first switching circuit. 
 
     
     
       8. The method of  claim 7  wherein bypassing at least a portion of the first electronic device with the second tunnel comprises passing through a first switch and not passing through a second switch. 
     
     
       9. The method of  claim 7  wherein the data for the first electronic device and the second electronic device is PCIe data. 
     
     
       10. The method of  claim 9  wherein the first tunnel is formed by a first PCIe adapter and the second tunnel is formed by a second PCIe adapter. 
     
     
       11. The method of  claim 10  wherein the first tunnel and the second tunnel are Thunderbolt compliant. 
     
     
       12. The method of  claim 7  wherein the first switching circuit does not provide the data for the second electronic device to the second switching circuit. 
     
     
       13. The method of  claim 12  where the first switching circuit is a Thunderbolt switch and the second switching circuit is a PCIe switch. 
     
     
       14. A method of transferring data among a plurality of electronic devices comprising:
 forming a first tunnel in a host device, the first tunnel for conveying data for a first electronic device; 
 forming a second tunnel in the host device, the second tunnel for conveying data for a second electronic device and a third electronic device; 
 using a first physical cable as a physical path for the first tunnel to transmit the data for the first electronic device from the host device to the first electronic device; 
 using the first physical cable as a physical path for the second tunnel to transmit the data for the second electronic device and the third electronic device from the host device to the first electronic device; 
 receiving the data for the first electronic device at the first electronic device; 
 bypassing at least a portion of the first electronic device with the second tunnel; 
 using a second physical cable as a physical path for the second tunnel to transmit the data for the second electronic device and the third electronic device from the first electronic device to the second electronic device; 
 receiving the data for the second electronic device and the third electronic device at the second electronic device; 
 forming a third tunnel in the second electronic device, the third tunnel for conveying data for the third electronic device; 
 using a third physical cable as a path for the third tunnel to transmit the data for the third electronic device from the second electronic device to the third electronic device; and 
 receiving the data for the third electronic device at the third electronic device. 
 
     
     
       15. The method of  claim 14  wherein bypassing at least a portion of the first electronic device with the second tunnel comprises passing through a first switch and not passing through a second switch. 
     
     
       16. The method of  claim 14  wherein the data for the first electronic device, the second electronic device, and the third electronic device is PCIe data. 
     
     
       17. The method of  claim 16  wherein the first tunnel is formed by a first PCIe adapter and the second tunnel is formed by a second PCIe adapter. 
     
     
       18. The method of  claim 17  wherein the third tunnel is formed by a third PCIe adapter. 
     
     
       19. The method of  claim 18  wherein the first tunnel, the second tunnel, and the third tunnel are Thunderbolt compliant. 
     
     
       20. The method of  claim 14  wherein receiving the data for the first electronic device at the first electronic device and bypassing at least a portion of the first electronic device with the second tunnel comprises:
 receiving the data for the first electronic device, the data for the second electronic device, and the data for the third electronic device at a first switching circuit in the first electronic device; 
 providing the data for the first electronic device to a second switching circuit in the first electronic device using the first switching circuit; 
 providing the data for the first electronic device to circuitry in the first electronic device using the second switching circuit; and 
 providing the data for the second electronic circuit and the third electronic circuit to the second cable using the first switching circuit. 
 
     
     
       21. The method of  claim 20  wherein the first switching circuit does not provide the data for the second electronic device and the third electronic device to the second switching circuit. 
     
     
       22. The method of  claim 21  where the first switching circuit is a Thunderbolt switch and the second switching circuit is a PCIe switch.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional patent application No. 61/446,027, filed Feb. 23, 2011, which is hereby incorporated by reference. 
    
    
     BACKGROUND 
     Computing environments are becoming increasingly complex. One reason is that computing tasks are becoming more complicated. Another is that extremely high-quality, specialized computing devices are becoming popular. 
     These ever increasingly complicated tasks have driven a recent evolutionary change to many people&#39;s computer systems, specifically, the inclusion of multiple display screens. For example, an electronic engineer may use one display to show a schematic of a portion of an electronic device and another display to show a layout of that portion of the electronic device. Also, these complicated tasks have led to increases in the amount of data that needs to be stored. In particular, video applications may be capable of generating huge amounts of data. In response, external hard drives have become a popular way to store this data. 
     The availability of specialized devices has also acted to increase many user&#39;s computing environments. For example, laptop computers have become so powerful that for many, they are not only a portable computing device, but have taken over duties as a desktop computer as well. But often times, perhaps at work or at home, users may want a bigger screen than a laptop may provide. In such a case, a larger, external display may be used. Also, a laptop may have a limited storage capacity. This, and a desire to perform backup tasks, may prompt a user to add an external storage drive. 
     To share data, these devices need to connect to each other, either through cables, wirelessly, or by using other means. When connecting these devices through these cables, it may be useful to be able to optimally utilize the bandwidth available at these connections. 
     Thus, what is needed are circuits, methods, and apparatus that may improve networking techniques for transferring data among various electronic devices. 
     SUMMARY 
     Accordingly, embodiments of the present invention may provide circuits, methods, and apparatus that may improve networking techniques for transferring data among various electronic devices. 
     An illustrative embodiment of the present invention may provide sharing data among various devices by daisy-chaining devices together. That is, several devices may be connected to each other through a series of cables to form a chain of devices. For example, a host device, such as a laptop, may connect to an external display through a first cable, while an external storage drive may connect to the display through a second cable. Data on these cables may be received by, and transmitted by, router chips or other appropriate devices. This configuration allows the host device, the laptop, to display graphics images on the display and to store data in the external drive. 
     With this physical connection, data may be shared among these devices in a number of ways. That is, various virtual connections may be configured given a set physical connection. Each virtual connection from one device to another may be referred to as a hop. A tunnel may be used to convey data from one device to one or more other devices, which may be referred to as destination devices. A tunnel may be one hop in length, or it may be multiple hops in length. A device where a tunnel terminates may be referred to as a target device. 
     In a specific embodiment of the present invention, data may be shared among multiple devices using a series of single-hop tunnels. This technique may provide for potentially very long daisy chains of devices at the cost of an increase in latency through the chain. 
     In another specific embodiment of the present invention, a number of tunnels may be formed by a host device. These tunnels may each have a target device in the daisy chain. Some of these tunnels may be multiple hops in length. Each tunnel may originate at the host device and terminate at their target device. Each tunnel may bypass devices, if any, between the host device and the tunnel&#39;s target device. This technique may reduce latency, but the length of a resulting daisy chain may be limited by the number of tunnels that may be formed by the host. In various embodiments of the present invention, the number of tunnels that may be formed by a host device may be limited by a number of available hardware resources. For example, a number of adapters for a particular protocol in the host device may limit the number of tunnels that may be formed. 
     In another specific embodiment of the present invention, these two techniques may be combined. For example, a number of tunnels may be formed by a host device, where each tunnel carries data for multiple destination devices. Each tunnel may originate in the host device and terminate in a target device. Each tunnel may bypass intermediate devices between the host device and their target device. A series of single-hop tunnels may then convey data from the target device to the tunnel&#39;s other destination devices. 
     Another illustrative embodiment of the present invention may provide a method of simplifying the routing of high-speed data signals through a network topology. In one example, a device may include two router devices. These router devices may be cross-coupled to connectors that may be connected to other electronic devices further down the daisy chain. By cross coupling these connectors, it does not matter which connector a downstream device connects to, the same data may appear on the same connector pins. Also, by cross-coupling these connectors, data may pass through a device having two router devices without that data having to be passed from one of the router devices to the other. 
     Various embodiments of the present invention may incorporate one or more of these and the other features described herein. A better understanding of the nature and advantages of the present invention may be gained by reference to the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a computer system that may be improved by the incorporation of embodiments of the present invention; 
         FIG. 2  illustrates a connection topology among router devices according to an embodiment of the present invention; 
         FIG. 3  illustrates a connection topology among routers according to an embodiment of the present invention; 
         FIG. 4  illustrates a connection topology among router devices according to an embodiment of the present invention; 
         FIG. 5  illustrates a network topology where an electronic device includes two router devices according to an embodiment of the present invention; and 
         FIG. 6  illustrates another network topology where a device includes two router devices according to an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
       FIG. 1  illustrates a computer system that may be improved by the incorporation of embodiments of the present invention. This figure, as with the other included figures, is shown for illustrative purposes and does not limit either the possible embodiments of the present invention or the claims. 
     This figure includes host device  110 , first electronic device  120 , and second electronic device  130 . In this example host device  110  is a laptop computer, while the first electronic device  120  and the second electronic device  130  are an external display and a hard drive. In other embodiments of the present invention, other types of devices may be connected together. Host device  110  may communicate with first electronic device  120  over cable  140 . First electronic device  120  may communicate with second electronic device  130  over cable  150 . In various embodiments of the present invention, cables  140  and  150  may be various types of cables. In a specific embodiment of the present invention, cables  140  and  150  may be Thunderbolt cables, though in other embodiments of the present invention, cables  140  and  150  may be DisplayPort cables, or other types of cables. 
     In various embodiments of the present invention, data may be transmitted and received over cables  140  and  150  using various types of circuitry. For example, router device or chips may be used to transmit and receive data over cables  140  and  150 . A specific example of such a router device or chip may be the “Light Peak” developed at least in part by Intel Corp. of Santa Clara, Calif., though in other embodiments of the present invention, other types of router devices or chips may be used. 
     In a specific embodiment of the present invention, various types of data may be transmitted over cables  140  and  150 . For example, DisplayPort or PCIe data may be transmitted using Thunderbolt packets over cables  140  and  150 . In other embodiments of the present invention, other types of data formatted in other ways may be transmitted over cables  140  and  150 . 
     In this example, cable  140  may carry data transmitted from host device  110  to first electronic device  120  and second electronic device  130 . Cable  150  may carry data from first electronic device  120  to second electronic device  130 . Similarly, cable  150  may carry data transmitted from second electronic device  130  to first electronic device  120 . Cable  140  may carry data transmitted from first electronic device  120  to host device  110 . 
     Once these physical connections are set, the virtual communication channels used to convey this data may be configured in various ways. For example, data may be transmitted over cables  140  and  150  using a series of one hop tunnels. This may provide an advantage in that very long daisy chained may be achieved. This long or large fanout, however, may come at the expense of increased latency. An example is shown in the following figure. 
       FIG. 2  illustrates a connection topology among router devices or chips (RCs) according to an embodiment of the present invention. In this example, each router chip may include a PCIe switch and a Thunderbolt switch. Each PCIe switch may have a number of adapters associated with it, which may form Thunderbolt tunnels for transmitting data. Each Thunderbolt switch may terminate a tunnel and provide PCIe data to its associated PCI switch. In various embodiments of the present invention, each Thunderbolt switch may also receive and transmit DisplayPort data, though these paths are left off these figures for clarity. 
     This figure illustrates a host device  210  connected to first device  220  over first cable  240 , and second device  230  connected to first device  220  over second cable  250 . 
     In this example, host device  210  may transmit data A to first device  220  and data B to second device  230 . Accordingly, host device  210  may form a first tunnel (A,B) to carry data A to first device  220 . The first tunnel (A,B) may be formed at a PCIe adapter associated with the PCIe switch in host device  210 . The first tunnel (A,B) may terminate at a Thunderbolt switch in first device  220 . Data A,B may be provided to its corresponding PCIe switch. The PCI switch may provide data A to circuitry coupled to the router chip in first device  220 . An adapter associated with the PCIe switch may form a second tunnel (B). Second tunnel (B) may be conveyed using second cable  250  to second device  230 . Data B may be provided through a corresponding PCIe switch to other circuitry in second device  230 . 
     In a specific embodiment of the present invention, each Thunderbolt switch may be able to route data received from a first cable directly to a second cable. In this way, a data path may bypass a PCIe switch in a router device and avoid its attendant format changes. This may reduce the overall latency through a chain of devices. An example is shown in the following figure. 
       FIG. 3  illustrates a connection topology among routers according to an embodiment of the present invention. In this example, host device  310  may communicate with first electronic device  320  through first cable  340 , while second device  330  may communicate with first device  320  through second cable  350 . 
     As before, host device  310  may transmit data A to first device  320 , and data B to second device  330 . Accordingly, data A and B may be received by the PCIe switch in host device  310 . Adapters associated with this PCIe switch may form separate tunnels for data A and data B. These two tunnels may convey data using first cable  340  to first device  320 . Tunnel (A) may terminate and data A may be provided by the PCIe switch to associated circuitry in first device  320 . Tunnel (B) may bypass the PCIe switch and exit the Thunderbolt switch on second cable  350 . In this configuration, tunnel (A) may be one hop long and tunnel (B) may be two hops long. Tunnel (B) may terminate at the Thunderbolt switch in second device  330 , and data B may be provided by the associated PCIe switch to circuitry in second device  330 . 
     In this way, the latency of data B may be reduced by bypassing the PCIe switch in first device  320 . However, the number of tunnels may be limited by hardware resources in host device  310 . For example, if a number of PCIe adapters that can tunnel PCIe data is limited to four, the maximum fanout from host device  310  is also four. Accordingly, embodiments of the present invention may provide a mix of the above to techniques. In this way, latency may be reduced, while maintaining long or large fanouts. An example is shown in the following figure. 
       FIG. 4  illustrates a connection topology among router devices according to an embodiment of the present invention. In this example, host device  410  may communicate with first electronic device  420  through first cable  440 , second device  430  may communicate with first device  420  through second cable  450 , while third device  460  may communicate with second device  430  through third cable  470 . 
     In this example, host  410  may transmit data A to first device  420 , data B to second device  430 , and data C to third device  460 . A first adapter in host device  410  may form a first tunnel for data A, and a second adapter may form a second tunnel for data B and C. Tunnels (A) and (B,C) may be conveyed using first cable  440 . Tunnel (A) may terminate in first device  420  and data A may be provided through its PCIe switch to associated circuitry. 
     Tunnel (B,C) may bypass the PCIe switch in first device  420  and exit the Thunderbolt switch on second cable  450 . This may allow data B and C to avoid the latency incurred with the PCIe switch in first device  420 . Tunnel (B,C) may terminate in second device  430 . In this way, tunnel (B,C) may be two hops long. Data B may be provided by the PCIe switch in second device  430  to circuitry in second device  430 . Tunnel (C) may be formed and provided on third cable  470 , where it may be received by third device  460 . The PCIe switch in third device  460  may provide this data to associated circuitry. 
     Again, in this example, data B and C may avoid the latency of a PCIE switch. Also, only the resources of two adapters in host device  410  are used transmit data to these three external devices. This tradeoff may help reduce latency while providing good fanout. 
     Devices consistent with various embodiments of the present invention may utilize multiple router devices. For example, some electronic devices may include two router chips or devices, though other devices may include more than two router chips or devices. When two or more devices are included, a first router device may be used to receive and provide data for the electronic device housing the routers, while a second router device may be used to send data to other electronic devices coupled downstream. To facilitate this, connector receptacles connected to the router devices may be cross coupled. This arrangement may allow multiple, high-bandwidth signal paths to use separate lanes, which may avoid bandwidth limitations that may otherwise result from sharing a single lane. An example is shown in the following figure. 
       FIG. 5  illustrates a network topology where an electronic device includes two router devices according to an embodiment of the present invention. This figure includes host device  510 , first electronic device  520 , and second electronic device  530 . First electronic device  520  may be connected to host device  510  through a single tethered cable  540 . That is, tethered cable may be dedicated to first electronic device  520  in that conductors in cable  540  attach to circuitry or other components inside first electronic device  520 , as opposed to connecting to first electronic device  520  through a connector in an enclosure of first electronic device  520 . Second electronic device  530  may be connected to first electronic device  520  through cable  550 . In this example, the first electronic device  520  may be a display device. 
     Again, in this example, host device  510  may be connected to first electronic device  520  through tethered cable  540 . This tethered cable may carry two lanes of data. A first lane of data may carry data A and X from connector  512  to a first router chip or device  524  in first electronic device  520 , while a second lane may carry data B from connector  512  to second router chip or device  526  in first electronic device  520 . Physically, these lanes may be specific wires in tethered cable  540 . They may terminate at one end at specific pins or contacts in connector  512 . In practical applications, connector  512  may be a composite of a connector insert attached to an end of tethered cable  540  and a connector receptacle in host device  510 . The lanes may be assigned to specific pins or contacts in the connectors. 
     Again, in this example, host  510  may transmit PCIe data A and DisplayPort data X to first electronic device  520 , and PCIe data B to second electronic device  530 . Accordingly, host device  510  may provide data A and X to a first lane defined by pins of connector  512  and data B to a second lane of connector  512 . First router chip  524  may provide PCIe data A and DisplayPort data X to associated circuitry in first electronic device  520 . (It should be noted that in these examples, associated circuitry is connected to the top router device or chip, such as router device  524 , and is not directly connected to the lower router device or chip, such as router chip  526 .) Second router chip or device  526  may provide data B to connector  522 . Second electronic device  530  may receive data B through cable  550  and connector  532 . In this example, data B may pass through electronic device  520 . That is, data B may not need to be passed from router device  524  to router device  526 . This may help reduce the latency of data B and saves power. It should also be noted that it does not matter which connector of second electronic device  520  that cable  550  is connected to. If cable  550  is connected to the lower connector receptacle, routing device  526  could be configured to deliver data B to that connector. 
     This arrangement may also be useful in load-balancing where two DisplayPort or other high-bandwidth signals are received by an electronic device, since each signal may be assigned to a separate lane and each routing device may handle one of these high-bandwidth signals. An example is shown in the following figure. 
       FIG. 6  illustrates another network topology where a device includes two router devices according to an embodiment of the present invention. This figure includes host device  610 , first electronic device  620 , third electronic device  630 , and fourth electronic device  660 . As before, first electronic device  620  may couple to host device  610  through tethered cable  640 . Second electronic device  630  may couple to first electronic device  620  through tethered cable  650 . Third electronic device  660  may couple to second electronic device  630  through cable  670 . In this example, first electronic device  620  and second electronic device  630  may be display devices. 
     In this example, host device  610  may transmit PCIe data A and DisplayPort data X to first electronic device  620 , DisplayPort data Y to second electronic device  630 , and PCIe data B to third electronic device  660 . Accordingly, host device  610  may provide data A, B, and X to a first lane on connector  612 , and data Y on a second lane of connector  612 . First routing device  624  in first electronic device  620  may provide PCIe data A and DisplayPort data X to internal circuitry. First routing device  624  may further provide data B to a second lane of connector  622 . Second routing device  626  may provide data Y to a first lane on connector  622 . 
     Second electronic device  630  may receive data Y and provides it to internal circuitry. Second routing chip  636  may provide data B to a first lane on connector  632 . Third electronic device  660  may receive data B. 
     In this example, host device  610  may provide two high-speed data signals X and Y. In this configuration, these high-speed signals may use separate lanes and separate routing chips. Again, this may help reduce latency, and may also help balance the bandwidth load among the various circuits. 
     More specifically, in this example, data X and Y may be DisplayPort signals, though in other configurations, they may be other types of data. These signals may consume a great deal of bandwidth, so much so that in some embodiments of the present invention, data X and Y may not be able to share a data lane. That is, the bandwidth requirements of data X and Y may exceed the bandwidth capacity of a single lane. Accordingly, this configuration allows data X to share a lane with data A and B, which may be lower bandwidth signals, while providing a separate lane for data Y. By allowing data X to have its own lane separate from data Y, host device  610  may provide DisplayPort data to first electronic device  620  and second electronic device  630 . 
     As can be seen in this example, the cross coupling router chip outputs at the connectors of first electronic device  620  and second electronic device  630  may allow the high-bandwidth data signals X and Y to be routed using separate lanes. For example, since data Y is not used by first electronic device  620 , it may be provided by host device  610  on a second lane that is received over tethered cable  640  by routing chip  626 . Routing device or chip  626  may then provide data Y on a first lane to either connector  622  or  623 , depending on where cable  650  is inserted. By providing data Y on this first lane, data Y may be received by router chip or device  634  in second electronic device  630 , which may provide it to associated circuitry, as shown. 
     It should be noted that without cross coupling, router chip  626  in first electronic device  620  may provide data Y on the second lane with data B, such that data Y would be received by routing device or chip  636 . In this case, routing chip  636  would have to provide data Y over connection  635  to routing chip or device  634 , which would then provide data Y to the associated circuitry. This extra jump over path  635  may add latency to data Y, consume extra power, and also slow the transmission of data B. 
     It should also be noted that the benefit of this configuration arises independently of the connector on the first electronic device that the tethered cable  650  is connected to. Specifically, if tethered cable  650  is connected to connector receptacle  623 , then routing device  626  in first electronic device  620  may provide data Y to routing device  634  in second electronic device  630  via connector receptacle  623 . 
     In various embodiments of the present invention, various connections may be made among routing chips or devices and connectors. In this example, a first input/output port on a first routing device may be connected to pins of a second lane on a first connector and a second input/output port on the first routing device may be connected to pins of a second lane on a second connector. Similarly, a first input/output port on a second routing device may be connected to pins of a first lane on a first connector and a second input/output port on the second routing device may be connected to pins of a first lane on a second connector. 
     The above description of embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Thus, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims.

Metadata:
Filing Date: 20120223
Publication Date: 20150224
Grant Date: 20150224
Priority Date: 20110223
Inventors: ANDERSON ERIC W.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F13/385", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F13/4221", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F13/4022", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F13/4027", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F13/385", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 46653700