Abstract:
In one embodiment of the invention, a method for providing a multi-mode port in a network device, includes: setting a first mode on the port, wherein the network device can perform serial communication on the port; and setting a second mode on the port, wherein the network device can perform network communication on the port. In another embodiment of the invention, an apparatus for enabling a multi-mode port in a network device, includes an adapter configured for attachment to and detachment from a connector of a port in the network device; wherein the network device can perform serial communication on the port in a first mode; and wherein the network device can perform network communication on the port in a second mode.

Description:
TECHNICAL FIELD  
       [0001]     Embodiments of the invention relate generally to communication networks, and more particularly to a multi-mode port in a network device. As an example, an embodiment of the invention permits the use of a standard Ethernet port and RJ45 connector for serial console access to a network device and for network communication by the network device.  
       BACKGROUND  
       [0002]     In current network devices (e.g., network switches or routers), forty-eight (48) network port connectors typically occupy a substantial portion of the front panel of the network device. Typically, an RJ45 connector is used as a network port connector. On the other hand, the serial port connector is a connector that consumes substantial space on the network device. Typically, the RS232 DB9 connector is used as a serial port connector. If the serial port connector is placed on the network device front panel, then the serial port connector will require the elimination of six current network ports from the network device front panel. It would be advantageous to not eliminate any of the current network ports in the front panel, so that various features can be implemented or supported on the network device.  
         [0003]     In other current network devices, if the serial port connector is not placed in the front panel, then the serial port connector is typically placed in a location that is usually not very accessible on the network device (e.g., the back or rear portion of the network device). By placing the serial port connector in the back or rear portion of the device, network personnel are subjected to significant inconvenience when attempting to access the serial port connector, particularly if the network device is already mounted on a rack.  
         [0004]     Therefore, the current technology is limited in its capabilities and suffers from at least the above constraints and deficiencies.  
       SUMMARY OF EMBODIMENTS OF THE INVENTION  
       [0005]     In one embodiment of the invention, a method for providing a multi-mode port in a network device, includes: setting a first mode on the port, wherein the network device can perform serial communication on the port; and setting a second mode on the port, wherein the network device can perform network communication on the port.  
         [0006]     In another embodiment of the invention, an apparatus for enabling a multi-mode port in a network device, includes: an adapter configured for attachment to and detachment from a connector of a port in the network device; wherein the network device can perform serial communication on the port in a first mode; and wherein the network device can perform network communication on the port in a second mode.  
         [0007]     These and other features of an embodiment of the present invention will be readily apparent to persons of ordinary skill in. the art upon reading the entirety of this disclosure, which includes the accompanying drawings and claims.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.  
         [0009]      FIG. 1  is a block diagram of a network system that includes an embodiment of the invention.  
         [0010]      FIG. 2  is a block diagram that illustrates the details of an adapter, in accordance with an embodiment of the invention.  
         [0011]      FIG. 3  is a block diagram that illustrates the details of an adapter, in accordance with another embodiment of the invention.  
         [0012]      FIG. 4  is a flowchart of a method in accordance with an embodiment of the invention.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0013]     In the description herein, numerous specific details are provided, such as examples of components and/or methods, to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that an embodiment of the invention can be practiced without one or more of the specific details, or with other apparatus, systems, methods, components, materials, parts, and/or the like. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of embodiments of the invention.  
         [0014]     Embodiments of the invention relate generally to communication networks, and more particularly to a multi-mode port in a network device. As an example, an embodiment of the invention permits the use of a standard Ethernet port and RJ45 connector for serial console access to a network device and for network communication by the network device. One specific embodiment of the invention permits a standard Ethernet 10/100 port to be used as either a network port and/or as a console RS232 port by use of a passive adapter as discussed below. In another embodiment of the invention, a smart adapter permits a Gigabit (10/100/100) port to be used as either a network port and/or as a console RS232 port by use of the smart adapter that negotiates with and changes the behavior of the Gigabit port.  
         [0015]      FIG. 1  is a block diagram of a network system  100  that includes an embodiment of the invention. A network device  105  includes a front panel  110  that supports multiple network port connectors. The network device  105  may be, for example, a switch or router or other suitable network device. Typically there are forty-eight (48) network port connectors that are supported by the front panel  110 . For purposes of describing an operation of an embodiment of the invention, only one network port connector  115  is shown on the front panel  110 . However, any suitable number of network port connectors can be supported by the front panel  115 . The network port connector  115  is typically an RJ45 connector (or another suitable equivalent type of connector) that is attached to the front panel  110 . As known to those skilled in the art, an RJ45 (Registered Jack-45) connector is an 8-pin connector that is used in networking.  
         [0016]     The network port connector  115  permits signal transmission to and from a port  116  in the network device  105 . As known to those skilled in the art, a network device will have multiple ports for receiving and transmitting signals.  
         [0017]     In a conventional network device, a serial port connector (i.e., console port connector) is also attached to the conventional network device, and the serial port connector is used for purposes of configuring the conventional network device. Typically, the serial port connector is placed in the back or rear side of the conventional network device. A DB9 serial connector is typically used as the serial port connector. As known to those skilled in the art, the DB9 connector is a connector used for RS-232 connections and for several video interfaces on IBM-compatible computers and/or other suitable applications. As also known to those skilled in the art, RS-232 is a standard for serial binary data interchange between a data terminal equipment and a data communication equipment. The serial port connector permits signals to be received to and transmitted from a console port. If the serial port connector is placed on the front panel of the conventional network device, then, typically, approximately six (6) of the 48 network port connectors will be removed from the front panel, since the serial port connector will occupy a large area amount of the front panel.  
         [0018]     In contrast, an embodiment of the invention provides an adapter  120  that permits a network port connector (network port connector  115  in the example of  FIG. 1 ) to be used for network communication (in one mode) and for serial communication (in another mode). Therefore, the use of the adapter  120  permits a network port  116  to function as a multi-mode port. The adapter  120  advantageously eliminates the prior need to use a separate serial connector on a network device. The adapter is shown in additional details in  FIG. 2 .  
         [0019]     The adapter  120  is attached ( 125 ) to the network port connector  115 , and a serial connector  130  is attached ( 135 ) to the adapter  120 , where the serial connector  130  is attached to a link  145  which is also attached to a computer  140 . The computer  140  can then be used to perform serial communication with the network device  105 , so that the computer  140  is used to configure the network device  105  via link  145 . The link  145  is typically a suitable cable that can be used to transmit control signals from the computer  140  to the network device  105 . The computer  140  is used, for example, to assign an Internet Protocol (IP) address to the network device  105 , to configure the ports in the network device  105 , to define a virtual LAN for the network device  105 , to define a host name, to define a default gateway, or/and other configuration and management operations. Therefore, the network port  116  can be used for receiving and sending RS232 serial configuration signals in this first mode, when the adapter  120  is attached to the network port connector  115 .  
         [0020]     When the adapter  120  is detached ( 150 ) from the network port connector  115  (or when the adapter is not attached to the network port connector  115 ) and a network connector  155  is attached ( 160 ) to the network port connector  115 , then the network device  105  will be connected via link  165  to a network  160 . Therefore, the network device  105  can perform network communication with other devices on the network  160 . The network  170  can be, for example, a local area network (LAN) that is based on the Ethernet technology or another type of network. Therefore, the network port  116  is used for network communication in this second mode, when the adapter  120  is removed from the network port connector  115  and when the network connector  155  is attached to the network port connector  115 .  
         [0021]      FIG. 2  is a block diagram that illustrates the details of an adapter  120 , in accordance with an embodiment of the invention. For purposes of describing the functionalities of embodiments of the invention, the components shown in  FIG. 2  are not necessarily drawn to scale.  
         [0022]     For purposes of describing the features of the adapter  120 , assume that the connector  115  on the network device  104  is an RJ45 connector, and the connector  130  on the cable  145  from computer  140  is a DB9 connector.  
         [0023]     In an RJ45 connector, the pins  1  to  3 , and  6  are used for network communications under the Ethernet technology. Therefore, an embodiment of the invention will use pins  4 ,  5 ,  7 , and  8  on the RJ45 connector  115  for serial communications, as described below.  
         [0024]     In a DB9 connector  130 , pin  2  is used for the received data (RXD), pin  3  is used for the transmitted data (TXD), and pin  5  is used for the signal ground (GND). Of course, as an alternative, pin  2  may be sued for the transmitted data (TXD) and pin  3  may be used for the received data (RXD).  
         [0025]     The adapter  120  includes a DB9 side (i.e., first side)  205  and an RJ45 side (i.e., second side)  210 . The DB9 connector  130  is connectable to and detachable from the DB9 side  205  of the adapter  120 . The RJ45 side  210  of the adapter  120  is connectable to and detachable from the RJ45 connector  115 .  
         [0026]     In the adapter  120 , pin  2  on the DB9 side  205  is electrically coupled to pin  4  on the RJ45 side  210 . For example, a conductor  215  may be used to electrically couple pin  2  on the DB9 side  205  to pin  4  on the RJ45 side  210 . Other techniques known to those skilled in the art may be used to electrically couple the pins described above. Therefore, the conductor  215  is not used in other configurations.  
         [0027]     In the adapter  120 , pin  3  on the DB9 side  205  is electrically coupled to pin  5  on the RJ45 side  210 . For example, a conductor  220  may be used to electrically couple pin  3  on the DB9 side  205  to pin  5  on the RJ45 side  210 .  
         [0028]     In the adapter  120 , pin  5  on the DB9 side  205  is electrically coupled to pins  7  and  8  on the RJ45 side  210 . For example, a conductor  225  may be used to electrically couple pin  5  on the DB9 side  205  to pins  7  and  8  on the RJ45 side  210 .  
         [0029]     To connect the adapter  120  to the network port connector  115  on the network device  105 , any 8-pin cable with RJ45 connectors could be used. The cable  145  should preferably be CAT5 (Category 5) or better. Alternatively, the cable  145  may be an 8-pin modular Telco cable. CAT3 cable will typically not be proper for use, since this cable type has only 2 pairs of wires and therefore, the utilized pins (pins  4 ,  5 ,  7 , and  8 ) on the RJ45 connector  115  will not be connected.  
         [0030]     For serial communication, only  3  wires (in the cable  145 ) and  3  pins will be required. These wires will be used for the receive signal (RXD), transmit signal (TXD), and ground (GND). The RXD and TXD signals are the RS232 signals that are used in configuring and managing the network device  105 , as known to those skilled in the art. When the adapter  120  is connected to the RJ45 connector  115  and to the DB9 connector  130 , the receive signal (RXD) will transmit from the serial communication module  230  to pin  4  (on the RJ45 connector  115  and on the RJ45 side  210 ), and along conductor  215  to pin  2  (on the DB9 side  205  and on the DB9 connector  130 ), and then along cable  145  to the computer  140 .  
         [0031]     When the adapter  120  is connected to the RJ45 connector  115  and to the DB9 connector  130 , the transmit signal (TXD) will transmit from the computer  140  along cable  145  to pin  3  (on the DB9 connector  130  and on the DB9 side  205 ), and along conductor  220  to pin  5  (on the RJ45 side  210  and on the RJ45 connector  115 ), and then to the serial communication module  230 .  
         [0032]     Alternatively, the RXD signal may instead transmit along pin  5  (on the RJ45 connector  115  and on the RJ45 side  210 ) to pin  3  (on the DB9 side  205  and on the DB9 connector  130 ). In this alternative configuration, the TXD signal would instead transmit along pin  2  (on the DB9 connector  130  and on the DB9 side  205 ) to pin  4  (on the RJ45 side  210  and on the RJ45 connector  115 ).  
         [0033]     When the adapter  120  is connected to the RJ45 connector  115  and to the DB9 connector  130 , the GND reference value along pin  5  (on the DB9 connector  130  and DB9 side  205 ) will also pull the pins  7  and  8  (on the RJ45 side  210  and on the RJ45 connector  115 ) to the same GND reference value. This GND reference value at pins  7  and  8  (on the RJ45 connector  115 ) will enable the serial communication logic  230  and disable the network communication logic  235 . Standard switching logic may be used to enable and disable the serial communication logic  230  and network communication logic  235 , in response to the presence or absence of the GND reference value at pins  7  and  8  on the RJ45 connector  115 . The serial communication logic  230  is typically the RS232 logic. The serial communication logic  230  and the network communication logic  235  are part of the network device logic  237  that permits the network device  105  to perform the intended functions or operations. Since the serial communication logic  230  is enabled, initial configuration (or management configuration) can be performed on the serial communication logic  230  in a manner known to those skilled in the art. Since the network communication logic  235  is disabled, network communication is not performed by the network device  105  during serial communication process.  
         [0034]     When the adapter  120  is disconnected from the RJ45 connector  115  and the network connector  155  (see  FIG. 1 ) is connected to the RJ45 connector  115 , the pins  7  and  8  on the RJ45 connector  115  are not at the ground reference level. Therefore, the GND reference signal is not received by the serial communication module  230  and the network communication module  235 . As a result, the serial communication module  230  will be disabled (and serial communication will not be performed by the network device  105 ), and the network communication module  235  is enabled (and network communication can performed by the network device  105 ).  
         [0035]     Therefore, when the adapter  120  is connected to the RJ45 connector  115  of port  116 , the serial communication logic  230  is enabled to permit serial communication between the network device  105  and a computer  140 , and the network communication logic  235  is also disabled. When the adapter  120  is disconnected from the RJ45 connector  115  of port  116  and the network connector  155  ( FIG. 1 ) is connected to the RJ45 connector  115 , the network communication logic  235  is enabled to permit network communication between the network device  105  and other devices on the network  170  ( FIG. 1 ), and the serial communication logic  230  is also disabled.  
         [0036]     The above method permits initial configuration of the RS232 logic  230  in the network device  105  and prevent damage of the RS232 logic  230  if the port  116  is also used as a network port.  
         [0037]     As an alternative feature in some embodiments of the invention, an indicator (e.g., a dual color light emitting diode (LED), multiple LEDs, or other indicator devices) can be used to notify the user of the particular mode or state of the network port  116 , depending on whether or not the adapter  120  is connected to the RJ45 connector  115  as discussed above.  
         [0038]     In another embodiment of the invention, a sense logic in the network device  105  is not used if the sense logic would be unpractical or/and too expensive in a particular application. Instead, a switch (e.g., a small pushbutton switch such as, for example, a recessed reset button in the network device  105  or in the adapter  120 ) can be used to change the mode or state of the network port  116 .  
         [0039]     On network device ports that are capable of supporting Gigabit over copper speeds (1000 Mbit), all cable pairs are used in the link to the RJ45 connector  115 . When the adapter  120  is currently attached to the network port  116  (via connector  115 ), the network port  116  would not sense a current network connection, and a state switch logic could turn on the serial communication logic  230  if pins  7  and  8  are connected to ground. The state switch logic could be implemented in the network device logic  237 . This configuration would be an inexpensive method to use the same adapter for all types of network devices.  
         [0040]      FIG. 3  is a block diagram that illustrates the details of a smart adapter  300 , in accordance with another embodiment of the invention. The smart adapter  300  can negotiate with the PHY logic and enable the serial communication logic  230  by this negotiation process  310 . This configuration would typically be more expensive to implement due to the additional components that would be required on the smart adapter  300 . The smart adapter  300  would include a negotiation logic stage  305  that performs handshaking and negotiation steps with a network device  105 . Network handshaking and negotiation techniques are well known to those skilled in the art.  
         [0041]      FIG. 4  is a flowchart of a method  400  in accordance with an embodiment of the invention. In block  400 , an adapter is provided in accordance with an embodiment of the invention.  
         [0042]     In block  410 , the adapter is attached to a connector of a port on the network device.  
         [0043]     In block  415 , a serial connector is attached to the adapter, where the serial connector is attached to a link which is attached to a computer.  
         [0044]     In block  420 , the computer is used to perform serial communication with the network device, so that the computer is used to configure the network device.  
         [0045]     In block  425 , when the adapter is not attached to the connector of the port (or when the adapter is detached from the connector of the port), a network connector is attached to the connector of the port.  
         [0046]     In block  430 , the network device can perform network communication with other devices on the network. Network communication is possible because the network connector attaches the network device to the network.  
         [0047]     Embodiments of the invention provide two major advantages. First, embodiments of the invention permit the saving of front panel space in the network device, so the use of the limited front panel space is optimized. Second, embodiments of the invention permit the saving of significant costs by not requiring the use of an extra DB9 serial connector on the network device and a cable that is typically custom made. Currently, the serial port of a network device is required to be accessed for purposes of initial configuration of the network device or for device recovery or management purposes. One disadvantage of current network devices is that the standard DB9 (9 pin) connector is significantly space consuming. In fact, a DB9 connector would occupy the space of six (6) RJ45 connectors that are stacked on top of each other. Since port density in the device front panel is increasingly becoming an issue due to new features being added on network devices, it would be desirable to maintain (or increase, if possible) the number of network ports in the device front panel and to not lose a space in the front panel with the serial port. In embodiment of the invention, for 10/100 ports on a network device, the currently unused pins  4  and  5  on an RJ45 connector (in a 10/100 port) can be used for transmitting and receiving, respectively, of RS232 signals. Alternatively, the unused pins  4  and  5  can be used for receiving and transmitting, respectively, of RS232 signals. Additionally, the pins  7  and  8  on an RJ45 connector can be connected together as ground, for purposes of enabling the RS232 logic in the network device and for purposes of preventing damage to the RS232 logic if the 10/100 port is used as a network port.  
         [0048]     Therefore, the invention solves the space and design issues and constraints on most managed network devices by eliminating the use of the bulky DB9 connector for the serial port. Instead, one port (e.g., port  1 ) on the device front panel can be used as a multi-mode network port and as a management serial port. The state (mode) of the port is changed when the adapter is connected to or removed from the port.  
         [0049]     Reference throughout this specification to “one embodiment”, “an embodiment”, or “a specific embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases “in one embodiment”, “in an embodiment”, or “in a specific embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.  
         [0050]     Other variations and modifications of the above-described embodiments and methods are possible in light of the foregoing disclosure.  
         [0051]     It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application.  
         [0052]     Additionally, the signal arrows in the drawings/Figures are considered as exemplary and are not limiting, unless otherwise specifically noted. Furthermore, the term “or” as used in this disclosure is generally intended to mean “and/or” unless otherwise indicated. Combinations of components or steps will also be considered as being noted, where terminology is foreseen as rendering the ability to separate or combine is unclear.  
         [0053]     As used in the description herein and throughout the claims that follow, “a”, “an”, and “the” includes plural references unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.  
         [0054]     The above description of illustrated embodiments of the invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize.  
         [0055]     These modifications can be made to the invention in light of the above detailed description. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification and the claims. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.