Method and system for network communications via a configurable multi-use ethernet PHY

Aspects of a method and system for network communications via a configurable multi-use Ethernet PHY are provided. In this regard, an Ethernet PHY may be configured based on characteristics of a network link over which the Ethernet PHY communicates, and a rate at which data is conveyed from a MAC to the Ethernet PHY may be controlled via a carrier sense signal of the MII. The carrier sense signal may be controlled based on a rate at which the Ethernet PHY transmits data over the network link. The Ethernet PHY may be configured based on a length of the network link and/or on a grade of the network link, where exemplary grades may comprise Cat-1 through Cat-7a cable. The Ethernet PHY may be configured into one of a plurality of modes comprising an Ethernet over digital subscriber line (DSL) mode, an extended reach mode, and a standard Ethernet mode.

Not Applicable

FIELD OF THE INVENTION

Certain embodiments of the invention relate to networking. More specifically, certain embodiments of the invention relate to a method and system for network communications via a configurable multi-use Ethernet PHY.

BACKGROUND OF THE INVENTION

With the increasing popularity of electronics such as desktop computers, laptop computers, and handheld devices such as smart phones and PDA's, communication networks are becoming an increasingly popular means of exchanging data of various types and sizes for a variety of applications. One set of networking technologies, namely Ethernet, has been particularly successful with regard to deployment in local area networks (LANs) and has made networking useful and affordable to individual and business customers of all levels and sizes. Everyday more and more devices are being equipped with Ethernet interfaces and Ethernet is increasingly being utilized to carry information of all types and sizes including voice, data, and multimedia. Due to the ubiquity of Ethernet in LANs, the advantages of using Ethernet in wide area networks are being recognized and Efforts such as Ethernet in the First Mile IEEE 802.3ah seek to realize these advantages. As the role of Ethernet expands to networks of all topologies and/or technologies, however, equipment manufacturers, service providers, and network administrators are presented with new economic and technological challenges.

BRIEF SUMMARY OF THE INVENTION

A system and/or method is provided for network communications via a configurable multi-use Ethernet PHY, substantially as shown in and/or described in connection with at least one of the figures, as set forth more completely in the claims.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention may be found in a method and system for network communications via a configurable multi-use Ethernet PHY. In various embodiments of the invention, a first Ethernet PHY may be configured based on characteristics of a network link over which the first Ethernet PHY communicates, and a rate at which data is conveyed from a first media access controller (MAC) to the first Ethernet PHY via a media independent interface (MII) may be controlled via a carrier sense signal of the MII. The carrier sense signal may be controlled based on a rate at which the first Ethernet PHY transmits data over the network link. The rate at which the first Ethernet PHY transmits data over the network link may be determined by monitoring a queue that buffers data to be transmitted. The carrier sense signal may be asserted when an amount of data stored in the queue is above a threshold. The carrier sense signal may be de-asserted when the amount of data stored in the queue is below a threshold. The first Ethernet PHY may be configured based on a length of the network link. The first Ethernet PHY may be configured based on a grade of the network link, where exemplary grades may comprise Cat-1 through Cat-7a cable. The first Ethernet PHY may be configured into one of a plurality of modes comprising an Ethernet over digital subscriber line (DSL) mode, an extended reach mode, and a standard Ethernet mode. The MII may comprise one of a media independent interface (MII), a gigabit MII (GMII), a reduced MII (RMII), reduced gigabit MII (RGMII), and 10 gigabit MII (XGMII).

In some embodiments of the invention, the first Ethernet PHY, the first MAC, a second Ethernet PHY, and a second MAC may be integrated within a network device. In such embodiments, data may be received by the second Ethernet PHY, buffered in a queue, and transmitted by the first Ethernet PHY, where the second Ethernet PHY receives the data at a rate that may be different than the rate at which the first Ethernet PHY transmits the data. In some instances, the second Ethernet PHY may be operable to request that a link partner pause or slow down transmission of data based on a status of the queue.

FIG. 1is a functional block diagram illustrating an exemplary Ethernet connection between two network devices, which may comprise configurable multi-use PHYs, in accordance with an embodiment of the invention. Referring toFIG. 1, there is shown a system100that comprises a network device102and a network device104. The network devices102and104may be link partners that communicate via the link112and may comprise, respectively, hosts106aand106b, networking subsystems108aand108b, PHY110aand110b, interfaces114aand114b, interfaces116aand116b, and interfaces118aand118b. The interfaces114aand114bare referenced collectively or separately herein as interface(s)114, and the interfaces116aand116bare referenced collectively or separately herein as interface(s)116. The hosts106aand106bare referenced collectively or separately herein as host(s)106. The networking subsystems108aand108bare referenced collectively or separately herein as networking subsystem(s)108. The PHY110aand110bare referenced collectively or separately herein as PHY(s)110.

The link112is not limited to any specific medium. Exemplary link112media may comprise copper, wireless, optical and/or backplane technologies. For example, a copper medium such as STP, Cat3, Cat 5, Cat 5e, Cat 6, Cat 7 and/or Cat 7a as well as ISO nomenclature variants may be utilized. Additionally, copper media technologies such as InfiniBand, Ribbon, and backplane may be utilized. With regard to optical media for the link112, single mode fiber as well as multi-mode fiber may be utilized. With regard to wireless, the network devices102and104may support one or more of the 802.11 family of protocols. In various embodiments of the invention, the network device102and the network device104may communicate via two or more physical channels comprising the link112. For example, Ethernet over twisted pair standards 10BASE-T and 100BASE-TX may utilize two pairs of UTP while Ethernet over twisted pair standards 1000BASE-T and 10GBASE-T may utilize four pairs of UTP.

The network devices102and/or104may comprise, for example, switches, routers, end points, computer systems, audio/video (A/V) enabled equipment, or a combination thereof. Additionally, the network devices102and104may be enabled to utilize Audio/Video Bridging and/or Audio/video bridging extensions (collectively referred to herein as audio video bridging or AVB) for the exchange of multimedia content and associated control and/or auxiliary data. Also, the network devices may be operable to implement security protocols such IPsec and/or MACSec.

The hosts106aand106bmay be operable to handle functionality of OSI layer3and above in the network devices102and104, respectively. The hosts106aand106bmay be operable to perform system control and management, and may comprise hardware, software, or a combination thereof. The hosts106aand106bmay communicate with the networking subsystems108aand108bvia interfaces116aand116b, respectively. The hosts106aand106bmay additionally exchange signals with the PHYs110aand110bvia interfaces118aand118b, respectively. The interfaces116aand116bmay correspond to PCI or PCI-X interfaces. The interfaces118aand118bmay comprise one or more discrete signals and/or communication busses. In various embodiments of the invention, one or both of the hosts106may comprise one or more queues115Zfor buffering received and/or to-be-transmitted data.

The networking subsystems108aand108bmay comprise suitable logic, circuitry, and/or code that may be operable to handle functionality of OSI layer2and above layers in the network device102and104, respectively. In this regard, networking subsystems108may each comprise a media access controller (MAC) and/or other networking subsystems. Each networking subsystem108may be operable to implement switching, routing, and/or network interface card (NIC) functions. Each networking subsystems108aand108bmay be operable to implement Ethernet protocols, such as those based on the IEEE 802.3 standard, for example. Notwithstanding, the invention is not limited in this regard. The networking subsystems108aand108bmay communicate with the PHYs110aand110bvia interfaces114aand114b, respectively. The interfaces114aand114bmay correspond to Ethernet interfaces that comprise protocol and/or link management control signals such as a carrier sense signal (CRS). The interfaces114aand114bmay be, for example, multi-rate capable interfaces and/or media independent interfaces (xxMII). In this regard, “media independent interface (MII)” is utilized generically herein and may refer to a variety of interfaces such as a media independent interface (MII), a gigabit MII (GMII), a reduced MII (RMII), reduced gigabit MII (RGMII), and 10 gigabit MII (XGMII). In various embodiments of the invention, one or both of the networking subsystems108may comprise one or more queues115Yfor buffering received and/or to-be-transmitted data.

The PHYs110may each comprise suitable logic, circuitry, interfaces, and/or code that may enable communication between the network device102and the network device104. Each of the PHYs110may be referred to as a physical layer transmitter and/or receiver, a physical layer transceiver, a PHY transceiver, a PHYceiver, or simply a PHY. The PHYs110aand110bmay be operable to handle physical layer requirements, which include, but are not limited to, packetization, data transfer and serialization/deserialization (SERDES), in instances where such an operation is required. Data packets received by the PHYs110aand110bfrom networking subsystems108aand108b, respectively, may include data and header information for each of the above six functional OSI layers. The PHYs110aand110bmay be configured to convert packets from the networking subsystems108aand108binto physical layer signals for transmission over the physical link112, and convert received physical signals into digital information. In some embodiments of the invention, the PHYs110may comprise suitable logic, circuitry, and/or code operable to implement MACSec. In various embodiments of the invention, one or both of the PHY devices110may comprise one or more queues115Xfor buffering receiving and/or to-be-transmitted data.

One or both of the PHYs110may comprise a twisted pair PHY capable of operating at one or more standard rates such as 10 Mbps, 100 Mbps, 1 Gbps, and 10 Gbps (10BASE-T, 100GBASE-TX, 1GBASE-T, and/or 10GBASE-T); potentially standardized rates such as 40 Gbps and 100 Gbps; and/or non-standard rates such as 2.5 Gbps and 5 Gbps. One or both of the PHYs110may comprise a backplane PHY capable of operating at one or more standard rates such as 10 Gbps (10GBASE-KX4 and/or 10GBASE-KR); and/or non-standard rates such as 2.5 Gbps and 5 Gbps. One or both of the PHYs110may comprise an optical PHY capable of operating at one or more standard rates such as 10 Mbps, 100 Mbps, 1 Gbps, and 10 Gbps; potentially standardized rates such as 40 Gbps and 100 Gbps; and/or non-standardized rates such as 2.5 Gbps and 5 Gbps. In this regard, the optical PHY may be a passive optical network (PON) PHY. One or both of the PHYs110may support multi-lane topologies such as 40 Gbps CR4, ER4, KR4; 100 Gbps CR10, SR10 and/or 10 Gbps LX4 and CX4. Also, serial electrical and copper single channel technologies such as KX, KR, SR, LR, LRM, SX, LX, CX, BX10, LX10 may be supported. Non-standard speeds and non-standard technologies, for example, single channel, two channel or four channels may also be supported. More over, TDM technologies such as PON at various speeds may be supported by the PHYs110.

Also, the PHYs110may support transmission and/or reception at a high(er) data in one direction and transmission and/or reception at a low(er) data rate in the other direction. For example, the network device102may comprise a multimedia server and a link partner may comprise a multimedia client. In this regard, the network device102may transmit multimedia data, for example, to the link partner at high(er) data rates while the link partner may transmit control or auxiliary data associated with the multimedia content at low(er) data rates. The network device102may also support wireless protocols such as the IEEE 802.11 family of standards.

Each of the PHYs110aand110bmay be operable to implement one or more energy efficient techniques, which may be referred to as energy efficient networking (EEN), or in the specific case of Ethernet, energy efficient Ethernet (EEE). For example, the PHYs110aand110bmay be operable to support low power idle (LPI) and/or subrating techniques, such as subset PHY for Copper based PHYs. LPI may generally refer a family of techniques where, instead of transmitting conventional IDLE symbols during periods of inactivity, the PHYs110aand110bmay remain silent and/or communicate signals other than conventional IDLE symbols. Subrating may generally refer to a family of techniques where the PHYs are reconfigurable, in real-time or near real-time, to communicate at different data rates.

In operation, For example, in some instances, data may be communicated from the network device102to the network device104over the link112. In such instances, the networking subsystem108amay communicate data via the interface114ato the PHY110aat a higher rate than the line rate, or other specified rate, at which the PHY110amay operable to output the data onto the link112. That is, the networking subsystem108aand the PHY110amay be mismatched with regard to an egress data rate. Consequently, a queue, such as one or more of the queues115, that store the egress data may eventually overflow. Accordingly, the rate at which the PHY110ais transmitting data and/or an amount of data waiting to be transmitted may be monitored and the PHY110amay notify the networking subsystem to hold off sending more data to the PHY110auntil the PHY110ais ready to receive more data without dropping or corrupting any data. In various embodiments of the invention, the PHY110amay notify the MAC108avia the CRS120aand/or by generating one or more pause frames and conveying the pause frames up to the networking subsystem108avia a receive path of the interface114a.

In various embodiments of the invention, the CRS120amay be controlled to match the rate at which data comes into the PHY110afrom the networking subsystem108with the rate at which the data is transmitted onto the link112. In this regard, the PHY110amay assert the CRS120aduring periods when the PHY110acannot handle additional data from the networking subsystem108a. For example, the PHY110amay be unable to handle additional data from the networking subsystem108awhen it is already transmitting data onto the link112at the line rate, or other specified maximum rate. The networking subsystem108amay, accordingly, defer transmission until the PHY110ade-asserts the CRS120a. The PHY110amay de-assert the CRS120awhen the PHY110acan handle additional data from the networking subsystem108a. For example, the PHY110amay be able to handle data from the networking subsystem108when the rate at which the PHY110acommunicates data onto the link112drops below the line rate, or other specified rate.

In various embodiments of the invention, the PHY110amay generate one or more pause frames and convey the pause frames up to the networking subsystem108aduring periods when the PHY110acannot handle additional data to be transmitted. For example, the PHY110amay be unable to handle additional data from the networking subsystem108awhen it is already transmitting data onto the link112at the line rate, or other specified maximum rate. Once the PHY110ais ready to received additional data from the networking subsystem108it may generate an unpause frame and convey the unpause frame up to the networking subsystem108a. The pause and unpause frames may be sent to the networking subsystem108as if they were frames received from a link partner. Accordingly, the networking subsystem108amay be operable to inspect received frames and distinguish pause and unpause frames from other received data. The networking subsystem108amay hold-off conveying data to be transmitted to the PHY110aduring periods of time between receiving a pause frame and receiving a corresponding unpause frame. An unpause frame may, for example, comprise a pause frame with a wait time field set to 0. Additionally or alternatively, an MAC may resume sending data to the PHY upon expiration of a timer without having received an unpause frame.

In some embodiments of the invention, one or more queues in which the egress data is buffered may be monitored to determine whether the PHY110ais ready to receive data from the networking subsystem108a. For example, in instances that a queue115in which the egress data is stored reaches a threshold, the PHY110amay assert the CRS120aand/or generate a pause frame to pause or slow down the data being output by the networking subsystem108a. Upon the occupied portion of the queue115dropping below a particular threshold, the PHY110amay de-assert the CRS120aand/or generate an unpause frame and, upon detecting the de-assertion of the CRS120aand/or the receipt of the unpause frame, the networking subsystem108amay resume sending data to the PHY110avia the interface114a.

In various embodiments of the invention, the Ethernet PHYs110may be configured based on characteristics of the link112. The configuration of the PHYs110may, in turn, determine the rate at which the PHYs110are operable to communicate over the link112. Exemplary characteristics of the link112factored into the configuration may comprise the length and/or grade or quality of the link112. For example, in a local area network (LAN) the link112may comprise up to 100 meters of CAT-5 UTP, whereas in an Ethernet over DSL application, the link112may comprise up to 2.7 km of CAT-1 UTP.

Controlling the flow of traffic between a MAC and PHY utilizing the CRS120may thus enable utilizing a single configurable PHY device in various applications. Moreover, utilizing the CRS to control the data flow may enable the configurable multi-use PHY110to interface to a legacy MAC, regardless of whether that MAC communicates full-duplex or half-duplex, and regardless whether the MAC was designed for communication over high quality UTP at less than 100 meters, such as the 10/100/1G/10GBASE-T protocols, or for communication over lower grade UTP and/or longer links, such as the 10PASS-TS or 2BASE-TL protocols. That is, a multi-use configurable PHY110may be compatible with MACs designed for LAN applications, Ethernet over DSL applications, and other applications.

FIG. 2Ais a diagram illustrating managing data transmission via a carrier sense signal of a media independent interface, in accordance with an embodiment of the invention. Referring toFIG. 2Athere is shown a networking subsystem108, a PHY110, a queue115, and corresponding values of a CRS120during a sequence of time instants T1-T5.

The networking subsystem108may be as described with respect toFIG. 1. The PHY110may be the same as the PHYs110aand110bdescribed with respect toFIG. 1. The queue115may be the same as one or more of the queues115X,115Y, and115Zdescribed with respect toFIG. 1. The CRS120may be the same as the CRS signals120aand120bdescribed with respect toFIG. 1.

At time instant T1, the queue115is not, or has not been, filled above the threshold204. Accordingly, the CRS120is de-asserted and the networking subsystem108is communicating data to the PHY110at a high(er) data rate (as indicated by the large arrow156) the PHY110is transmitting data onto the link112a low(er) rate (as indicated by the small arrow158), where the rate at which the PHY110transmits onto the link112may be determined based on characteristics of the link112.

At time instant T2, the queue115may have more data buffered in it than at time instant T1; however, the amount of data has still not surpassed the threshold204and thus the CRS120remains de-asserted and the data continues to be communicated from the networking subsystem108to the PHY110.

At time instant T3, the amount of data in the queue115has risen above the threshold204and thus the CRS120may be asserted and/or a pause frame may be generated and conveyed to the networking subsystem108. The PHY110may continue to drain the queue115by transmitting data onto the link112.

At time instant T4, the PHY110may continue to transmit data and drain the queue115; however, hysteresis may be utilized to prevent rapid toggling of the CRS120and thus, the CRS120may be de-asserted only when the level of data in the queue115drops below the threshold206. Accordingly, the CRS120may remain asserted and communication from the networking subsystem108to the PHY110may remain paused.

At time instant T5, the amount of data in the queue115may drop below the threshold206, accordingly the CRS120may be de-asserted and/or a pause frame may be generated and conveyed to the networking subsystem108and data may again be communicated from the networking subsystem108to the PHY110.

FIG. 2Bis a flow chart illustrating exemplary steps for managing communication of data from a MAC to a PHY via a carrier sense signal of a media independent interface, in accordance with an embodiment of the invention. Referring toFIG. 2B, from start step222, the exemplary steps may advance to step224in which it may be determined whether there is data pending conveyance from a MAC to a PHY via an xxMII. In instances that there is no to-be-transmitted data pending communication from the MAC to the PHY, the steps may remain in step224until there is data to be communicated to the PHY. In instances that there is data pending communicated from the MAC to the PHY, the exemplary steps may advance to step226.

In step226it may be determined whether a CRS signal of the xxMII between the MAC and PHY is asserted. In instances, that the CRS is asserted, the exemplary steps may advance to step234.

In step234, the MAC may hold off communication of data to the PHY until the PHY de-asserts the CRS. In this regard, the PHY110may de-assert the CRS signal when the amount of data buffered in a transmit queue drops below a threshold. Subsequent to step234, the exemplary steps may return to step224.

Returning to step226, in instances that the CRS is not asserted, the exemplary steps may advance to step228. In step228, the MAC may communicate data to the PHY. Subsequent to step228, the exemplary steps may advance to step230.

In step230, data communicated from the MAC to the PHY may be stored in a queue and it may be determined whether the additional data in the queue has filled the queue above a threshold. In instances that the queue is not filled above the threshold the exemplary steps may return to step224. In instances that the queue is filled above the threshold the exemplary steps may advance to step232.

In step232the PHY may assert the CRS. Subsequent to step232, the exemplary steps may advance to step234.

In step234, the PHY may wait for the amount of data buffered in the queue to be below a threshold as data is read out from the queue and transmitted. Once the queue is below the threshold the PHY may de-assert the CRS and the exemplary steps may return to step224

FIG. 3is a functional block diagram illustrating a PHY configurable based on characteristics of a link over which it communicates, in accordance with an embodiment of the invention. Referring toFIG. 3there is shown a PHY310and a MAC308.

The PHY310may be similar to or the same as the PHYs110aand110bdescribed with respect toFIG. 1. The MAC308may be similar to or the same as the networking subsystem108, or a portion thereof, described with respect toFIG. 1. The CRS120may be as described with respect toFIG. 1.

The PHY310may comprise suitable logic, circuitry, interfaces, and/or code that may enable the PHY310to be configured into various modes of operation. The configurability of the PHY310is represented by the switching element316controlled by a signal314. Additionally, as described with respect toFIGS. 1,2A, and2B, the PHY310may be operable to control the flow of data from the MAC308via the CRS120and/or by generating pause frames.

The link detection and/or characterization module318may comprise suitable logic, circuitry, code, and/or interfaces that may be operable to determine characteristics of the link304and generate the control signal314accordingly. Exemplary characteristics that may be determined by the module318may comprise length, grade, and/or number of available channels or conductors of the link304.

In operation, the switching element316may be configured to select an appropriate mode of operation for communicating over the network link304. In some embodiments of the invention, the PHY310may comprise the module318and configuration of the PHY310may be controlled based on an automatic link detection and/or characterization. In other embodiments of the invention, control signal314, and thus configuration of the PHY310, may be controlled via software and/or manually by a network administrator, application, or end-user.

FIG. 4Ais a diagram illustrating use of a configurable multi-use PHY for Ethernet over DSL communications, in accordance with an embodiment of the invention. Referring toFIG. 4A, there is shown a network device400communicatively coupled to a broadband access network402and a link partner408. The network device400comprises a controller412, a memory414, and Ethernet PHYs310aand310b, which are operable to communicate over links404and406, respectively.

The broadband access network402may be owned and/or operated by a service provider such as a telephone company. The broadband access network402may provide Internet connectivity to homes and business utilizing DSL.

The controller412may comprise suitable logic, circuitry, interfaces, and/or code that may be operable to process data and/or control operations of the network device400. With regard to processing data, the controller412may enable packetization, de-packetization, transcoding, reformatting, and/or otherwise processing data received from and/or to be transmitted by the network device400. With regard to controlling operations of the network device400, the controller412may be enabled to provide control signals to the various other portions of the network device400. In this regard, the controller412may be operable to make decisions and/or generate signals for configuring the Ethernet PHYs310aand310b. The controller412may also control data transfers between various portions of the network device400. The controller412may enable execution of applications programs and/or code. In this regard, the applications, programs, and/or code may enable, for example, parsing, transcoding, or otherwise processing of data. Furthermore, the applications, programs, and/or code may enable, for example, configuring or controlling operation of the Ethernet PHYs310aand310band/or the memory414.

The memory414may comprise suitable logic, circuitry, and/or code that may enable storage or programming of information that includes parameters and/or code that may effectuate the operation of the network device400. The parameters may comprise configuration data and the code may comprise operational code such as software and/or firmware and the parameters may include adaptive filter and/or block coefficients, but the information need not be limited in this regard. Additionally, the memory400may buffer or otherwise store received data and/or data to be transmitted. In various embodiments of the invention, the memory400may store instructions, parameters, of other information for configuring the Ethernet PHYs310aand310b. Each of the Ethernet PHYs310aand310bmay be the same as the PHY310, which is described with respect toFIG. 3.

In operation, the Ethernet PHYs310aand310bmay be configured for communication over the respective links404and406. In an exemplary embodiment of the invention, the link404may comprise voice grade UTP designed and/or suited for DSL and the link406may comprise less than 100 meters of CAT-5e UTP. Accordingly, the Ethernet PHY310amay be configured into an Ethernet over DSL mode and the Ethernet PHY310bmay be configured into a standard Ethernet mode. In this regard, the coding and signaling techniques utilized by the Ethernet PHY310amay adhere to, for example, 10PASS-TS or 2BASE-TL. In this regard, the network device400may function as a modem, router, and/or switch to provide Internet access to devices such as the device408. The Ethernet PHY310b, on the other hand, may utilize coding and signaling techniques that adhere to, for example, one of 10BASE-T, 100BASE-T, 1000BASE-T, or 10GBASE-T.

The protocols and link characteristics described with regard toFIG. 4Aare for illustration purposes and the invention is not so limited. Also, the network device400comprises two PHYs for illustration only and a device such as network device400may comprise any number of Ethernet PHYs each of which may be configurable and/or may communicate over copper, optical fiber, or backplane.

FIG. 4Bis a diagram illustrating use of a configurable multi-use PHY for extended reach Ethernet communications, in accordance with an embodiment of the invention. Referring toFIG. 4B, there is shown a network device400communicatively coupled to a broadband access network420and a link partner408. The network device400, its PHYs310aand310b, controller412, and memory414may be as described with respect toFIG. 4A.

The broadband access network402may be owned and/or operated by a service provider such as a telephone company. The broadband access network402may provide internet connectivity to homes and businesses utilizing Extended reach Ethernet techniques such as those described in United States patent application Ser. No. 61/101,072 filed on Sep. 29, 2009, and United States patent application Ser. No. 12/495,496 filed on Jun. 30, 2009, referenced and incorporated in paragraph [0001] above. In this regard, the rate at which the broadband access network420communicates with the network device400may be adapted based on characteristics of the link424, where exemplary characteristics comprise a grade of the link, a length of the link, a number of channels available on the link, temperature of the link, and interference present on the link.

In operation, the Ethernet PHYs310aand310bmay be configured for communication over the respective links424and406. In an exemplary embodiment of the invention, the link424may comprise more than 100 meters of Cat-5e UTP and the link406may comprise less than 100 M of CAT-5e UTP. Accordingly, the Ethernet PHY310amay be configured for extended reach Ethernet and the Ethernet PHY310bmay be configured into a standard Ethernet mode. In this regard, the rate at which data is communicated over the link424and/or the number of channels of the link424over which data is communicated may be configured based on the characteristics of the link424. Adjusting the data rate of communications on the link424may compensate, for example, for the increased delay, noise, and/or attention of the link424. In this regard, the network device400may function as a modem, a switch, and/or a router to provide Internet access to devices such as the device408. The Ethernet PHY310b, on the other hand, may communicate over the link406may at a standard rate as defined by, for example, 10BASE-T, 100BASE-T, 1000BASE-T, or 10GBASE-T.

The protocols and link characteristics described with regard toFIG. 4Bare for illustration purposes and the invention is not so limited. For example, both links may be longer than 100M and both Ethernet PHYs310aand310bmay be configured into an Extended reach mode. Also, the network device400comprises two PHYs for illustration only and a device such as network device400may comprise any number of Ethernet PHYs each of which may be configurable and/or may communicate over copper, optical fiber, or backplane.

FIG. 4Cis a diagram illustrating use of a configurable multi-use PHY for standard Ethernet communications, in accordance with an embodiment of the invention. Referring toFIG. 4B, there is shown a network device400communicatively coupled to a link partner432and a link partner408. The network device400, its PHYs310aand310b, controller412, and memory414may be as described with respect toFIG. 4A.

In operation, the Ethernet PHYs310aand310bmay be configured for communication over the respective links434and406. In an exemplary embodiment of the invention, the links434and406may each comprise less than 100 meters of CAT-5e UTP. Accordingly, the Ethernet PHYs310aand310bmay be configured into a standard Ethernet mode. In this regard, the network device400may function as a network switch, network controller, and/or a router between the devices432and408and possibly additional devices not shown inFIG. 4C. The Ethernet PHYs310aand310bmay each communicate over the link406at a standard rate as defined by, for example, 10BASE-T, 100BASE-T, 1000BASE-T, or 10GBASE-T, and in some instances may communicate at different rates, which may be non-standard rates.

The protocols and link characteristics described with regard toFIG. 4Bare for illustration purposes and the invention is not so limited. For example, both links may be longer than 100 meters and both Ethernet PHYs310aand310bmay be configured into an extended reach mode. Also, the network device400comprises two PHYs for illustration only and a device such as network device400may comprise any number of Ethernet PHYs each of which may be configurable and/or may communicate over copper, optical fiber, or backplane.

FIG. 5Ais a functional block diagram illustrating a network device operable to convey data between network links having different characteristics, in accordance with an embodiment of the invention. Referring toFIG. 5A, there is shown a network device500comprising Ethernet PHYs310aand310b, MACs308aand308b, and memory512. The Ethernet PHYs310aand310band the MACs308aand308bmay be as described with respect toFIG. 3.

The memory512may comprise suitable logic, circuitry, interfaces, and/or code that may be operable to buffer data being conveyed between the MACs308aand308b.

In operation, data may be received via one of the Ethernet PHYs310aand310band transmitted via the other of the PHYs310aand310b. The PHY310amay be configured based on characteristics of the link504and the PHY310bmay be configured based on characteristics of the link504. Accordingly, the rate at which the data is transmitted by one of the PHYs310aand310bmay be different than the rate at the data may be transmitted via the other of the PHYs310aand310b. For example, the links502and504may comprise different physical media, comprise different grades of physical media, be different lengths, be coupled to different types of network devices, and/or comprise a different numbers of channels. Consequently, as data is received via the Ethernet PHY310afor transmission via the Ethernet PHY310bthe different data rates may be matched by buffering data in the memory512.

In an exemplary embodiment of the invention, data may arrive via the Ethernet PHY310afaster than the Ethernet PHY310bmay transmit the data. Consequently, the Ethernet PHY310bmay utilize CRS120bto control the transfer of data from the MAC308bto the Ethernet PHY310b, which in turn may determine the rate at which the MAC308breads data from the memory512. Consequently, the memory512may eventually reach a level or capacity that is beyond a particular threshold and the memory512may be unable to receive more data from the MAC308auntil additional data is read from the memory512and transmitted by the Ethernet PHY310b. An indication that the memory512is filled above the particular threshold may be provided to the MAC308avia a signal506a. Upon detecting that the memory512is at a level above the particular threshold, the MAC308aand/or the PHY310amay notify the link partner sending the data. As a result, the link partner may pause transmission of the data or alter a rate at which it transmits the data to the network device500. In this manner, the network device500may be operable to utilize a back pressure to control data transmitted to the network device500by a link partner. Additional details of controlling traffic in the network device500are described with respect toFIGS. 5B and 5Cbelow.

In one embodiment of the invention, the network device500may be a MACSec PHY adapted to convert between two data rates and/or network links. In this regard, a second PHY310bmay be instantiated or coupled to a MACSec PHY such that the MACSec PHY is operable to interface to two network links. In this regard, the network device500may be configurable to operate as a MACSec PHY or as a converter between two network links. The memory512may either be utilized for implementing MACSec protocols or for buffering data to rate match the network link502and the network link504.

FIG. 5Bis a flow chart illustrating exemplary steps for controlling ingress data flow in a network device that conveys data between network links having different characteristics, in accordance with an embodiment of the invention. Referring toFIG. 5B, start step532, the exemplary steps may advance to step534. In step534, it may be determined whether the memory512is at a level that is above a particular threshold, where the threshold may be configurable. In instances that the memory512is not at a level that is above the particular threshold, the exemplary steps may advance to step536.

In step536, the PHY310aand MAC308amay be configured and/or prepared to receive data. In this regard, in some instances the MAC308aand/or the PHY310amay be enabled to operate in an energy saving mode and in step536the MAC308aand/or the PHY310amay transition out of the energy saving mode and may be trained and/or synchronized with a link partner. Upon receiving data from the link partner, the exemplary steps may advance to step538.

In step538the PHY310amay process the received data and convey the received data to the MAC308a. The MAC308amay store the data in the memory512. Subsequent to step538, the exemplary steps may advance to step534.

Returning to step534, in instances that the memory512is at a capacity or level that is above the particular threshold, the exemplary steps may advance to step540. In step540, the MAC308aand/or319amay generate one or more signals or otherwise notify link partner(s) to pause or slow transmission of data to the network device500. Subsequent to step540, the exemplary steps may advance to step542.

In step542, the MAC308aand/or the PHY310amay wait for the memory512to drain below a particular threshold. In this regard, the duration of the wait may depend on the rate at data from the memory512by the MAC308band being transmitted by the PHY310b. In some embodiments of the invention, portions of the network device500, such as the MAC308aand/or the PHY308a, may transition to an energy saving mode during this time. Once an amount of data buffered in the memory512drops below the particular threshold, the exemplary steps may advance to step544.

In step544, the MAC308aand/or the PHY310amay stop applying back pressure to the link partner and/or notify the link partner to resume transmission of data to the network device500. Subsequent to step544, the exemplary steps may advance to step536.

FIG. 5Cis a flow chart illustrating exemplary steps for controlling egress data flow in a network device that conveys data between network links having different characteristics, in accordance with an embodiment of the invention. Referring toFIG. 5C, subsequent to start step542, the exemplary steps may advance to step544.

In step544, it may be determined whether there is data to be transmitted that is buffered in the memory512. In instances that there is data buffered in the memory512, the exemplary steps may advance to step548. In step548, it may be determined whether the CRS120bis asserted. In instances that CRS120bis not asserted, the exemplary steps may advance to step552. In step552, the MAC308bmay read data out of the memory512, process it accordingly, and convey it to the PHY310b. The PHY310bmay process the data accordingly and transmit it onto the link504. Subsequent to step552, the exemplary steps may advance to step544. Returning to step548, in instances that CRS120bis asserted, the exemplary steps may advance to step550. In step550, the MAC308bmay hold-off or defer reading data from the memory512and conveying the data to the PHY310buntil CRS120bis de-asserted. Upon de-assertion of the CRS120b, the exemplary steps may advance to step552.

Returning to step544, in instances that there is no buffered data in the memory512, which is pending transmission, the exemplary steps may advance to step546. In step546the MAC308band the PHY310bmay await arrival of data to be transmitted. In some embodiments of the invention, the MAC308b, the PHY310b, and/or other portions of the network device500may be configured to operate in an energy saving mode during this time.

Various aspects of a method and system for network communications via a configurable multi-use Ethernet PHY are provided. In an exemplary embodiment of the invention, a first Ethernet PHY310may be configured based on characteristics of a network link304over which the first Ethernet PHY310communicates, and a rate at which data is conveyed from a first media access controller (MAC)308to the first Ethernet PHY310via a media independent interface (MII)114may be controlled via a carrier sense signal120of the MII114. The carrier sense signal120may be controlled based on a rate at which the first Ethernet PHY310transmits data over the network link304. The rate at which the first Ethernet PHY310transmits data over the network link304may be determined by monitoring a queue115that buffers data to be transmitted. The carrier sense signal120may be asserted when an amount of data stored in the queue115is above a threshold.

The carrier sense signal120may be de-asserted when the amount of data stored in the queue115is below a threshold. The first Ethernet PHY310may be configured based on a length of the network link304. The first Ethernet PHY310may be configured based on a grade of the network link, where exemplary grades comprise Cat-1 through Cat-7a cable. The first Ethernet PHY310may be configured into one of a plurality of modes comprising an Ethernet over digital subscriber line (DSL) mode, an extended reach mode, and a standard Ethernet mode. The MII114may comprise one of a media independent interface (MII), a gigabit MII (GMII), a reduced MII (RMII), reduced gigabit MII (RGMII), and 10 gigabit MII (XGMII).

In some embodiments of the invention, a first Ethernet PHY310b, a first MAC308b, a second Ethernet PHY310a, and a second MAC308amay be integrated within a network device500. In such embodiments of the invention, data may be received by the second Ethernet PHY310a, buffered in a queue512, and transmitted by the first Ethernet PHY310b, where the second Ethernet PHY310amay receive the data at a rate different than the rate at which the first Ethernet PHY310btransmits the data. In some instances, the second Ethernet PHY310amay be operable to request that a link partner pause or slow down transmission of data based on a status of the queue512.