Dual-media network interface that automatically disables inactive media

A dual-media network interface includes a physical layer device. A first interface module communicates with the physical layer device via a medium dependent interface. A link indicator indicates a communications link with the physical layer device via the first interface module. The physical layer device transmits a link indication signal to the link indicator and a small form-factor pluggable (SFP) interface module when the physical layer device establishes a communications link via the first interface module. The link indication signal activates the link indicator and disables the SFP interface module. The dual-media network interface is a single-port network interface and only one of the first interface module or the SFP interface module is active at a time. The first interface module is a copper media interface module. The SFP interface module is one of a copper media interface module or a fiber optic media interface module.

FIELD OF THE INVENTION

The present invention relates to dual-media network interfaces, and more particularly to dual-media network interfaces that include small form-factor pluggable (SFP) interface modules.

BACKGROUND OF THE INVENTION

Dual-media network interfaces support two separate interfaces for a single port of a network device. For example, a single port of an Ethernet network interface may include a first interface for a copper medium and a second interface for a fiber optic medium. However, both interfaces may also support the same types of media. Dual-media network interfaces allow flexibility by providing a user with an option between two potentially different media. Additionally, dual-media network interfaces allow users to utilize redundant network connections. For example, if a first interface of a dual-media network interface fails, the dual-media network interface may be programmed to automatically switch to a second interface that includes a redundant network connection. Such redundant network connections reduce network downtime.

Some dual-media network interfaces include small form-factor pluggable (SFP) interfaces that support SFP modules. SFP modules are interchangeable plug-in transceivers that are typically hot-swappable and provide interfaces for desired media. For example, SFP modules commonly provide interfaces for high-speed fiber optic media. However, SFP modules provide interfaces for other media such as copper media. SFP modules allow a user to quickly and inexpensively repair or upgrade a network device. For example, if an SFP module fails, the SFP module can be replaced without soldering components. Simultaneous active links for a single port of a dual-media network interface can cause significant network disruption and/or downtime including a total network failure. Therefore, only one interface of a dual-media network interface is active at a time.

Referring now toFIG. 1, a dual-media network interface10includes a medium access control (MAC) device12that communicates with a physical layer device14(or PHY). The physical layer device14communicates with first and second interfaces16and18. The first interface16(labeled “A” inFIG. 1) is an SFP interface between the physical layer device14and an SFP module20. The second interface18(labeled “B” inFIG. 1) is illustrated as a medium dependent interface (MDI) such as a copper media interface, although the second interface18may be another type of interface. For example, the second interface18may be hard-wired and controlled by the physical layer device14. Conversely, the SFP module20includes an independent physical layer device22that controls network communications between the SFP module20and external devices.

As discussed above, it is undesirable for the first and second interfaces16and18, respectively, to simultaneously establish links between the physical layer device14and external devices. In one approach, the physical layer device14utilizes link monitoring software to determine when either the first or second interface16or18, respectively, establishes a link. For example, a processor23may execute the link monitoring software and communicate with the physical layer device14via management data input/output and management data clock (MDC/MDIO) signals.

The processor23is capable of reading registers in the physical layer device14via the MDC/MDIO signals in order to monitor links between the physical layer device14and external devices. For example, the link monitoring software may periodically poll the first and second interfaces16and18to detect when one of the first or second interfaces16or18, respectively, establishes a link. When a link is detected at one of the first or second interfaces16or18, respectively, the link monitoring software ceases communications via the other of the first or second interfaces18or16, respectively. For example, the link monitoring software may cease communications via an interface16or18by disabling an internal module that is dedicated to the particular interface16or18.

Since the second interface18is controlled by the physical layer device14, the link monitoring software is capable of quickly and completely ceasing communications via the second interface18when a link is detected at the first interface16. However, it is possible for the independent physical layer device22to retain a link with an external device even after the link monitoring software ceases communications via the first interface16. For example, in order to disable the SFP module20, the processor23may first transmit a signal to the MAC device12, which is then forwarded to a disable pin24of the SFP module20(identified as TX_DIS inFIG. 1). In this case, an appreciable delay occurs from the time when the processor23first detects a link at the second interface18to the time when the MAC device12disables the SFP module20via the disable pin24.

Additionally, the delay may be further extended when the processor23is busy processing other data unrelated to the dual-media network interface10. For example, a network device25that includes the dual-media network interface10may include a large number of ports. In this case, the external device may still detect a link with the dual-media network interface10and attempt to send packets, which may create a disruptive renegotiation loop or other network congestion when the external device does not detect a response. Also, during the period of time both the first and second interfaces16and18, respectively, are capable of establishing links on the same port, which can cause significant network disruption.

SUMMARY OF THE INVENTION

A dual-media network interface according to the present invention includes a physical layer device. A first interface module communicates with the physical layer device via a medium dependent interface. A small form-factor pluggable (SFP) interface module communicates with the physical layer device. A link indicator indicates a communications link with the physical layer device via the first interface module. The physical layer device transmits a link indication signal to the link indicator and the SFP interface module when the physical layer device establishes a communications link via the first interface module. The link indication signal activates the link indicator and disables the SFP interface module.

In other features, the dual-media network interface is a single-port network interface and only one of the first interface module or the SFP interface module is active at a time. The first interface module is a copper media interface module. The copper media interface module interfaces with media that is compliant with at least one of 1000BASE-T, 100BASE-TX, and/or 10BASE-T standards. The SFP interface module interfaces with media that is compliant with at least one of 100BASE-FX, 10BASE-T, 100BASE-T, and/or 1000BASE-T standards.

In still other features of the invention, the SFP interface module is one of a copper media interface module or a fiber optic media interface module. The SFP interface module communicates with the physical layer device via at least one of a serial gigabit medium independent interface (SGMII), a 4-byte/5-byte (4B/5B) local fiber interface, and/or a serializer/deserializer (SERDES) interface. The physical layer device includes an SFP control module. The physical layer device disables the SFP control module when the physical layer device establishes a communications link via the first interface module. The physical layer device includes a copper control module. The physical layer device disables the copper control module when the physical layer device establishes a communications link via the SFP interface module. A medium access control (MAC) device communicates with the physical layer device.

In yet other features, the physical layer device includes a link status pin. The physical layer device asserts the link status pin when the physical layer device establishes a communications link via the first interface module. The SFP interface module includes a disable pin that communicates with the link status pin. The SFP interface module is disabled when the physical layer device asserts the link status pin. The link indicator communicates with the link status pin. The link indicator is activated when the physical layer device asserts the link status pin. The link indicator is a light-emitting diode (LED). A network device comprises the dual-media network interface.

A dual-media network interface according to the present invention includes a first copper media interface module. A physical layer device includes a copper link status pin and asserts the copper link status pin when the physical layer device establishes a communications link via the first copper media interface module. A copper link indicator indicates a communications link with the physical layer device via the first copper media interface module and communicates with the copper link status pin. A small form-factor pluggable (SFP) interface module includes an SFP disable pin. The SFP disable pin communicates with the copper link status pin. The copper link indicator is activated and the SFP interface module is disabled when the physical layer device asserts the copper link status pin.

In other features, the dual-media network interface is a single-port network device and only one of the first copper media interface module or the SFP interface module is active at a time. The first copper media interface module interfaces with media that is compliant with at least one of 1000BASE-T, 100BASE-TX, and/or 10BASE-T standards. The SFP interface module interfaces with media that is compliant with at least one of 100BASE-FX, 10BASE-T, 100BASE-T, and/or 1000BASE-T standards. The SFP interface module is one of a second copper media interface module or a fiber optic media interface module. The first copper media interface module communicates with the physical layer device via a medium dependent interface (MDI). The SFP interface module communicates with the physical layer device via at least one of a serial gigabit medium independent interface (SGMII), a 4-byte/5-byte (4B/5B) local fiber interface, and/or a serializer/deserializer (SERDES) interface.

In still other features of the invention, the physical layer device includes an SFP control module. The physical layer device disables the SFP control module when the physical layer device establishes a communications link via the first copper media interface module. The physical layer device includes a copper control module. The physical layer device disables the copper control module when the physical layer device establishes a communications link via the SFP interface module. A medium access control (MAC) device communicates with the physical layer device. The copper link indicator is a light-emitting diode (LED). A network device comprises the dual-media network interface.

A method for operating a dual-media network interface according to the present invention includes providing a first interface module that communicates with a physical layer device via a medium dependent interface. A small form-factor pluggable (SFP) interface module is provided that communicates with the physical layer device. A communications link is established via the first interface module. A link indication signal is transmitted to a link indicator and the SFP interface module. The link indication signal activates the link indicator and disables the SFP interface module.

In other features, the dual-media network interface is a single-port network interface and only one of the first interface module or the SFP interface module is active at a time. The first interface module is a copper media interface module. The copper media interface module interfaces with media that is compliant with at least one of 1000BASE-T, 100BASE-TX, and/or 10BASE-T standards. The SFP interface module interfaces with media that is compliant with at least one of 100BASE-FX, 10BASE-T, 100BASE-T, and/or 1000BASE-T standards.

In still other features of the invention, the SFP interface module is one of a copper media interface module or a fiber optic media interface module. The SFP interface module communicates with the physical layer device via at least one of a serial gigabit medium independent interface (SGMII), a 4-byte/5-byte (4B/5B) local fiber interface, and/or a serializer/deserializer (SERDES) interface. A communications link is established via the first interface module. An SFP control module in the physical layer device is disabled. A communications link is established via the SFP interface module. A copper control module in the physical layer device is disabled. A medium access control (MAC) device communicates with the physical layer device.

In yet other features, a communications link is established via the first interface module. A link status pin is asserted. The SFP interface module is disabled during the asserting step. The SFP interface module includes a disable pin that communicates with the link status pin. The link indicator is activated during the asserting step. The link indicator communicates with the link status pin. The link indicator is a light-emitting diode (LED). The dual-media network interface is integrated into a network device.

A method for operating a dual-media network interface according to the present invention includes providing a first copper media interface module that communicates with a physical layer device. A communications link is established via the first copper media interface module. A copper link status pin is asserted. A small form-factor pluggable (SFP) interface module is provided that includes an SFP disable pin. A copper link indicator is activated and the SFP interface module is disabled during the asserting step. The SFP disable pin and the copper link indicator communicate with the copper link status pin.

In other features, the dual-media network interface is a single-port network device and only one of the first copper media interface module or the SFP interface module is active at a time. The first copper media interface module interfaces with media that is compliant with at least one of 1000BASE-T, 100BASE-TX, and/or 10BASE-T standards. The SFP interface module interfaces with media that is compliant with at least one of 100BASE-FX, 10BASE-T, 100BASE-T, and/or 1000BASE-T standards. The SFP interface module is one of a second copper media interface module or a fiber optic media interface module. The first copper media interface module communicates with the physical layer device via a medium dependent interface (MDI). The SFP interface module communicates with the physical layer device via at least one of a serial gigabit medium independent interface (SGMII), a 4-byte/5-byte (4B/5B) local fiber interface, and/or a serializer/deserializer (SERDES) interface.

In still other features of the invention, a communications link is established via the first copper media interface module. An SFP control module in the physical layer device is disabled. A communications link is established via the SFP interface module. A copper control module in the physical layer device is disabled. A medium access control (MAC) device communicates with the physical layer device. The copper link indicator is a light-emitting diode (LED). The dual-media network interface is integrated into a network device.

A dual-media network interface according to the present invention includes communications configuring means for specifying a data communications configuration. First interfacing means communicates with the communications configuring means via a medium dependent interface. Pluggable interfacing means communicates with the communications configuring means. Link indicating means indicates a communications link with the communications configuring means via the first interfacing means. The communications configuring means transmits a link indication signal to the link indicating means and the pluggable interfacing means when the communications configuring means establishes a communications link via the first interfacing means. The link indication signal activates the link indicating means and disables the pluggable interfacing means.

In other features, the dual-media network interface is a single-port network interface and only one of the first interfacing means or the pluggable interfacing means is active at a time. The first interfacing means is a copper media interface module. The copper media interface module interfaces with media that is compliant with at least one of 1000BASE-T, 100BASE-TX, and/or 10BASE-T standards. The pluggable interfacing means interfaces with media that is compliant with at least one of 100BASE-FX, 10BASE-T, 100BASE-T, and/or 1000BASE-T standards.

In still other features of the invention, the pluggable interfacing means is one of a copper media interface module or a fiber optic media interface module. The pluggable interfacing means communicates with the communications configuring means via at least one of a serial gigabit medium independent interface (SGMII), a 4-byte/5-byte (4B/5B) local fiber interface, and/or a serializer/deserializer (SERDES) interface. The communications configuring means includes pluggable controlling means for configuring the pluggable interfacing means. The communications configuring means disables the pluggable controlling means when the communications configuring means establishes a communications link via the first interfacing means. The communications configuring means includes interface controlling means for configuring the first interfacing means. The communications configuring means disables the interface controlling means when the communications configuring means establishes a communications link via the pluggable interfacing means. Medium controlling means for controlling use of a medium communicates with the communications configuring means.

In yet other features, the communications configuring means includes link communicating means for communicating link status. The communications configuring means asserts the link communicating means when the communications configuring means establishes a communications link via the first interfacing means. The pluggable interfacing means includes disabling means for disabling the pluggable interfacing means that communicates with the link communicating means. The pluggable interfacing means is disabled when the communications configuring means asserts the link communicating means. The link indicating means communicates with the link communicating means. The link indicating means is activated when the communications configuring means asserts the link communicating means. The link indicating means is a light-emitting diode (LED). A network device comprises the dual-media network interface.

A dual-media network interface according to the present invention includes first copper interfacing means for interfacing with copper media. Communications configuring means for specifying a data communications configuration includes link communicating means for communicating link status and asserts the link communicating means when the communications configuring means establishes a communications link via the first copper interfacing means. Link indicating means for indicating a communications link with the communications configuring means via the first copper interfacing means communicates with the link communicating means. Pluggable interfacing means for communicating with the communications configuring means includes disabling means for disabling the pluggable interfacing means. The disabling means communicates with the link communicating means. The link indicating means is activated and the pluggable interfacing means is disabled when the communications configuring means asserts the link communicating means.

In other features, the dual-media network interface is a single-port network device and only one of the first copper interfacing means or the pluggable interfacing means is active at a time. The first copper interfacing means interfaces with media that is compliant with at least one of 1000BASE-T, 100BASE-TX, and/or 10BASE-T standards. The pluggable interfacing means interfaces with media that is compliant with at least one of 100BASE-FX, 10BASE-T, 100BASE-T, and/or 1000BASE-T standards. The pluggable interfacing means is one of second copper interfacing means or fiber optic interfacing means for interfacing with fiber optic media. The first copper interfacing means communicates with the communications configuring means via a medium dependent interface (MDI). The pluggable interfacing means communicates with the communications configuring means via at least one of a serial gigabit medium independent interface (SGMII), a 4-byte/5-byte (4B/5B) local fiber interface, and/or a serializer/deserializer (SERDES) interface.

In still other features of the invention, the communications configuring means includes pluggable controlling means for configuring the pluggable interfacing means. The communications configuring means disables the pluggable controlling means when the communications configuring means establishes a communications link via the first copper interfacing means. The communications configuring means includes interface controlling means for configuring the first copper interfacing means. The communications configuring means disables the interface controlling means when the communications configuring means establishes a communications link via the pluggable interfacing means. Medium controlling means for controlling use of a medium communicates with the communications configuring means. The link indicating means is a light-emitting diode (LED). A network device comprises the dual-media network interface.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A dual-media network interface according to the present invention automatically disables interfaces associated with inactive media when a link is established at another interface. The dual-media network interface prevents independent physical layer devices associated with small form-factor pluggable (SFP) modules from establishing or maintaining links with external devices after another interface previously establishes a link.

Referring now toFIG. 2, an exemplary network device32includes a dual-media network interface34having a medium access control (MAC) device36that communicates with a physical layer device38(or PHY). The dual-media network interface34includes an SFP interface40and a copper interface42. The SFP interface40communicates with the physical layer device38through a serial gigabit medium independent interface (SGMII) or another interface such as a 4-byte/5-byte (4B/5B) local fiber interface or a serializer/deserializer (SERDES) interface. In an exemplary embodiment, the SFP interface40supports SFP modules that interface with fiber media according to 100BASE-FX standards. Alternatively or additionally, the SFP interface40supports SFP modules that interface with copper media according to 10BASE-T, 100BASE-T, and/or 1000BASE-T standards and/or other current or future Ethernet standards.

The copper interface42communicates with the physical layer device38through a medium dependent interface. For example, the copper interface42may be hard-wired and solely controlled by the physical layer device38. Additionally, the copper interface42may include an RJ-45 connector with or without integrated magnetics (MAG). In an exemplary embodiment, the copper interface42interfaces with copper media according to 10BASE-T, 100BASE-TX, and/or 1000BASE-T standards.

The physical layer device38includes an SFP control module44that is associated with the SFP interface40and a copper control module46that is associated with the copper interface42. The physical layer device38ceases communications via the SFP interface40and/or the copper interface42by disabling the SFP control module44and/or the copper control module46, respectively. For example, the physical layer device38may utilize link monitoring software that detects established links at the SFP and copper interfaces40and42, respectively. The dual-media network interface34includes an SFP link indicator48and a copper link indicator50. For example, the SFP and copper link indicators48and50, respectively, may be light-emitting diodes (LEDs) or other types of indicators48and50that indicate the presence of an established link to a user. The physical layer device38activates the copper link indicator50when a link is established at the copper interface42. Likewise, the physical layer device38activates the SFP link indicator48when a link is established at the SFP interface40.

According to an exemplary embodiment, the physical layer device38includes a copper link indication pin52and an SFP link indication pin54. The physical layer device38asserts the copper link indication pin52and disables the SFP control module44when a link is established at the copper interface42. Likewise, the physical layer device38asserts the SFP link indication pin54and disables the copper control module46when a link is established at the SFP interface40. For example, disabling the copper control module46disables the copper interface42. The physical layer device38may assert the copper link indication pin52and SFP link indication pin54by outputting a logical high signal, a logical low signal, or another signal at a specific voltage or within a specific voltage range.

The SFP interface40supports an SFP module56including an independent physical layer device58. Therefore, disabling the SFP control module44alone does not necessarily prevent the SFP module56from establishing a link with an external device. Communications standards typically require that SFP interfaces40include a disable pin60. The SFP interface40and the SFP module56are disabled when the disable pin60is asserted. For example, the SFP module56may include a disable pin62that communicates with the disable pin60of the SFP interface40. According to the present invention, the disable pin60of the SFP interface40communicates with the copper link indication pin52. Therefore, when the physical layer device38asserts the copper link indication pin52, the SFP interface40and the SFP module56are automatically and immediately disabled.

Since the copper interface42is solely controlled by the copper control module46, the copper interface42is automatically disabled when the physical layer device38disables the copper control module46. Additionally, the SFP interface40and SFP module56are automatically disabled when a link is established at the copper interface42. Therefore, the present invention avoids problems associated with double linking that can occur when a processor performs link monitoring. For example, in prior art systems, software delays in processors prevent the physical layer device38from immediately disabling the SFP module56when a link is established at the copper interface42.

According to the present invention, double linking is avoided in this case because the physical layer device38does not wait for the link monitoring software to first detect the link at the copper interface42and then take action. Instead, the SFP interface40and SFP module56are disabled as soon as the physical layer device38detects the link at the copper interface42and activates the copper link indicator50. Therefore, the SFP interface40and the SFP module56will already be disabled by the time the link monitoring software detects the link at the copper interface42. Therefore, there is no longer an overlap in time where the SFP and copper interfaces40and42, respectively, are capable of simultaneously establishing links. Additionally, the independent physical layer device58in the SFP module56is unable to retain a link with an external device after a link is established at the copper interface42.

SFP modules56that interface with fiber media will typically shut down automatically and refrain from establishing links with external devices when the physical layer device38disables the SFP control module44. However, the SFP module56may still establish a link with an external device when unintentional signal conditions such as noise occur. Therefore, unintentional links with external devices are avoided by completely disabling both the SFP interface40and the SFP module56when a link occurs at the copper interface42.

Referring now toFIG. 3, a link detection algorithm begins in step64. In step66, the physical layer device38initializes the SFP interface40and the copper interface42as inactive. In step68, control determines whether a link has been established at either the SFP interface40or the copper interface42. If false, control loops to step68. If true, control proceeds to step70. In step70, control determines whether the link was established at the copper interface42. If false, control proceeds to step72. If true, the physical layer device38activates the copper link indicator50in step74.

Since the disable pin60is tied to the copper link indication pin52, the physical layer device38also disables the SFP interface40by activating the copper link indicator50. In step76, the physical layer device38disables the SFP control module44and control ends. In step72, the physical layer device38activates the SFP link indicator48. In step78, the physical layer device38disables the copper control module46and control ends. Since the copper interface42is completely controlled by the physical layer device38, the copper interface42is also disabled in step78.