WO2011002398A1

WO2011002398A1 - Method and arrangement for enabling link status propagation

Info

Publication number: WO2011002398A1
Application number: PCT/SE2010/050681
Authority: WO
Inventors: Wei-Ping Huang
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2009-06-30
Filing date: 2010-06-17
Publication date: 2011-01-06
Anticipated expiration: 2011-12-30
Also published as: US20120102239A1; US8824280B2; EP2449417B1; EP2449698A1; EP2449417A1; EP2449698A4; EP2449417A4; US8788722B2; CN102474353A; WO2011002397A1; US20120099427A1

Abstract

A system and method for implementation of a process that propagates a link status across a media converter system implemented in a telecom and/or data com network is provided. More specifically, the system comprise XAUI and PMA/PMD interfaces that support both a copper cable and the different types of SFP+/SFP fiber-optic pluggable modules for accessing a host system and a remote link partner, respectively. With the method, the link statuses at both the copper and fiber-optic link sides of the media converter system are being monitored, such that a change of link status at one side of the media converter system will automatically be propagated across the media converter system to the other side, by dynamically enabling or disabling a respective XAUI or PMD transmitter at the opposite side of a physical layer device (PHY) of the media converter system.

Description

MEIHO D AND ARRANGEMENT R) R ENABDNG DNK STATUS PRO PAG ATIO N

TECHNIC ALFMD

[0001] The present invention relates generally to a method and an arrangement for enabling link status propagation in a network configuration comprising an IP transport network interconnected to an IPbased host system.

BACKGROUND

[0002] Due to its proven low implementation cost, reliability, and relative simplicity of installation and maintenance, Ethernets popularity has grown to the point that nearly all data traffic on the Internet originates or terminates with an Ethernet connection. With increasing demands of data rates, 10 Gigabit Ethernet, normally referred to as 10GbE, nowadays becomes the natural evolution and the widely adopted technology both in telecommunication and data communication networks.

[0003] A study group established with IEEES02.3 specifies the standards used for 10GbE One of the mostinteresting 10GbE standards refer to 10GBASECX4

(IEEES02.3ak) that specifies a physical layer device (PHY) for providing 10Gb/ s over 44ane copper cables, i.e. the so-called CX4 cable, which is similar to the

corresponding varieties used in the known InfiniBand™ and DensiShield™

technologies. The introduction of 10GBASECX4 gains its popularity for use in data communication networks mainly due to advantages of low per-portcost, low power consumption and low latency.

[0004] Hgure 1 is a simplified schematic overview exemplifying a conventional network configuration comprising an IPbased host system 100 which is interconnected with an IP transport network 102 via two separate lines, namely a working line, comprising a first pair of link paths 105a/ 105b, and a protecting line, comprising a second pair of link paths 105a7 105b', where the protecting line has a main purpose of providing for redundancy in the network configuration.

[0005] Fbr providing both lines and equipment protection, two switches 101a, 101b, typically 10GbE switches, belonging to the host system is connected to its remote link partner, i.e. IP transport network 102, for the link path redundancy, via a respective router 103a, 103b, typically a lOGbErouter. Here, one par of switch and router is used for the working line 105a/ 105b and the other par is used for the protection line 105aV 105b', respectively. I^" a link failure occurs in the working line, the redundancy protection systems used by any of the IPbased host system 100 and the IP transport network 102 will switch traffic from the failing working line to the protection line, or vice versa if the failing working line is recovered.

[0006] The 10GBA.SECX4 protocol which is a typical protocol for supporting an interconnection e.g. via a CX4 cable, specifies a maximum working distance which is limited to 15m only. Such a limited working distance makes it difficultly to cover the basic demand in the telecom network, which typically ranges from a 200m working distance for interconnecting applications up to a working distance of a few tens of km for long-haul applications. In order to reach a desired working distance, a media converter system, or more specifically a 10GbE media converter system, is needed for the 10GBA.SECX4 based host system to connect the remote link partner.

[0007] M order to meet the requirements of longer operating distances a new solution for the system described above with reference to figure 1 will be needed. Hgure 2 is another simplified schematic overview, exemplifying an alternative network configuration where two media converter systems, such as e.g. 10GbE media converter systems, have been deployed into the link paths between the switches 101a, 101b and the routers 103a, 103b for the main purpose of increasing the operating link distance. With the help of media converter systems, a link distance up to 40 000 m ean be achieved. [0008] The media converter system typically converts a copper-based formatted signal, i.e. 10GBASECX4, into fiber-optic based formatted signals, such as e.g.

10GBASESR/ -IR/ -ERspecified by IEEES02.3ae, or lOGBase-IRM specified by

IEEE802.3aq. Since the media converter system only works at the physical network layer, it makes the whole conversion process transparent to the higher layer network devices, e.g. the Ethernet switc he s, which imply that it will not introduce any

interference with higher layer functions in the network

[0009] A media converter may e.g. be used for supporting a special application where the system of the remote link partner, e.g. a IGbE switch, is designed to run a low data rate with the fiber-optic based 1000Base-X protocol. With the help of a SEPl 00 OBa se -ZX transceiver module and Single mode optical fibers (SME), it may even be possible for a 10GbE media converter system to support data traffic over an 80 000 m transmission distance.

[0010] Eor a modem lOGbEmedia converter system, itis designed to supporttiie fiber-optic based pluggable transceiver modules. The well-known fiber-optic based pluggable transceivers for 10GbE applications include the various types known as e.g. XENPAK, XPAK, X2, XFP and SEP+. With the help of these modules, multiple protocols, such as e.g. lOGBASESR/ -IR/ -FH -IRM can be supported by the same lOGbEmedia converter system, by exchanging the pluggable transceiver that is operated using the specific protocol specified by both the host system and its remote link partner.

[0011] Due to the similarity of mechanical construction, the same lOGbEmedia converter system designed for SEP+ pluggable transceiver module may also be used to support fiber-optic based and/ or copper-cable based SEP pluggable transceiver modules that run formatted signals with lower data rate protocols, such as e.g.

1000Base-SX -IX/ -ZX specified by IEFE302.3z or 1000base-T specified by

IEEF802.3ab, respectively. Eor the lOGbEmedia converter system, the operating mode supporting SEPpluggable transceiver modules often refers to the so-called IGbE bypass mode.

[0012] The lOGbEmedia converter is usually designed to have atleastone channel including a par of ports, one port for connecting the CX4 copper cable to set up the link with the host system and the other one designed to support the fiberoptic based pluggable transceiver module to be connected to the remote link partner, respectively. By carefully selecting the pluggable transceiver modules and different types of the fibers, e.g. multimode fiber (MMF), or single mode fiber (SMF), a link distance from a few tens of meters up to 40000 meters can be achieved.

[0013] Itis well-known practice to use a redundant system for the duplication of a critical link in a network such as the one described in figures 1 to ensure the network connectivity and reliability. M practice, the link protection is done by using at least two link lines, i.e. an active line, or working line, and a standby line, or a protecting line, ff the link supported by the working line fails, the change of link status will normally be simultaneously notified by the redundant systems of both link partners atboth ends of the link path, thus the redundant system of both link partners will simultaneously switch the data traffic onto the protecting line within typically a few tens of ms up to a few hundreds of ms. In such a way, network connectivity can be maintained and protected within the network configuration.

[0014] However, after introducing a media converter system in the link path of a network such as the one described in figure 2, the network connectivity may notbe guaranteed anymore. This is because the media converter system creates an interconnecting node inside the link path, meaning that, if a link failure occurs atone side of media converter system, such as e.g. at the fiber-optic link path side, the opposite link of media converter system, i.e. the side of copper link path, may still be set-up properly. Thus, the redundancy systems of both link partners will notbe triggered to simultaneously switch the data traffic onto the protecting line, which will most likely lead to the complete loss of data traffic in the network Thus, there are reasons to address the problem of network connectivity caused by the introduction of an interconnecting node.

SUMMAET

[0015] The objectof the present document is to address the problems outlined above. Li particular, it is an objectof the present document to provide a solution that enables link status to propagate in a network configuration comprising an IP transport network interconnected to an IP based host system, without requiring any user interaction.

[0016] These objects and others may be obtained by using the method and arrangement according to the attached independent claims.

[0017] According to one aspecta method of supporting link status propagation in a network configuration, comprising a media converter system interconnecting an IP based host system with an IPbased transport network is provided. The method is executable in a network configuration where the IPbased host system is connected to the media converter system via a first pair of link paths and the IPbased transport network is connected to the media converter system via a second pair of link paths. According to one exemplary embodiment a link status change atone of the link paths is automatically propagated across the media converter system to the opposite link path by enabling a corresponding transmitter (PMD-TX; XAUI-TX) in case it is disabled, or by disabling a corresponding transmitter (PMD-TXjXAUI-TX) in case it is enabled.

[0018] An advantage with applying the suggested method is thus that a link status change will be propagated across a media converter system without requiring any manual user interaction.

[0019] More specifically, the suggested method may include a monitoring of respective link statuses of the first and the second pair of link paths in order to register link status changes, of disabling the corresponding transmitter (IMIKDζXAUI-TX) in case it is enabled and in case a link status change to a loss of link (IDI) status of the link paths is recognized during the monitoring, and of enabling the corresponding transmitter (XAUI-TX; IMD-TX) in case it is disabled and in case a link status change from a IOLstatus of one of the link paths is recognized during the monitoring.

[0020] The monitoring step may typically comprise a monitoring of transmitter link status registers of a physical layer device (IHY) of the media converter system

104;104'. Furthermore, the enabling/ disabling steps may comprise a further step of updating an alarm signal list according to a monitored link status change, such that updated alarm information on the executed enabling or disabling step can be accessed whenever needed. More specifically, an alarm signal indicating a monitored link status change to a IOLstatus may be sentto a local & remote management interface 311 of the media converter system in case atleastone of the mentioned transmitters has been disabled.

[0021] The network configuration at which the suggested method is to be executed typically comprises two parallel lines, thereby providing redundancy to the network, where each line comprises a first pair of link paths and a second pair of link paths. Li such a scenario the method may comprise the further step of switching from a first pair of link paths and a corresponding second pair of link paths of one of the lines to the first and the second pair of link paths of the other line in response to recognizing an alarm signal indicating a link status change to the IOLstatus.

[0022] The media converter system is typically supporting a plurality of channels, N channels, and wherein the method steps mentioned above are executable on a per channel basis for each of the N channels, according to pre-defined settings. Typically such a process is executable at least upon each booting or rebooting the media converter system

[0023] According to another aspect an arrangement provided in a media converter system where the arrangement is configured to execute the method described above is also provided. The arrangement is provided with a process controlling function which is configured to enable for a link status change occurring atone of the link paths to automatically propagate across the media converter system to the opposite link path by instructing an enabling/ disabling function to enable a

corresponding transmitter (HVUKDζXAUI-TX) in case it is disabled, or to disable a corresponding transmitter (HVUKDζXAUI-TX) in case it is enabled, in response to recognizing that the link status change has occurred.

[0024] The arrangement typically further comprise a monitoring function configured to monitor a respective link status of the first and the second pair of link paths, such that link status changes can be recognized, wherein the

enabling/ disabling function is configured to disable the corresponding transmitter (IMIKDζXAUI-TX) in case it is enabled, in response to being notified by the monitoring function of a link status change to a loss of link (IDI) status, and to enable the corresponding transmitter (HVUKDζXAUI-TX) in case it is disabled, in response to being notified by the monitoring function of a link status change from a IOLstatus. The monitoring function is typically configured to execute the monitoring in real-time.

[0025] The arrangement is also typically provided with receiver link status registers, wherein the monitoring function is configured to execute the monitoring steps by monitoring the respective receiver (IMD-RX;XAU[-RJO link status registers of a IHY of the media converter system.

[0026] The arrangement may also be provided with an alarm generating function configured to update an alarm signal list according to a monitored link status change recognized by the monitoring function. More specifically, the alarm generating function may be configured to forward an alarm signal indicating a monitored link status change to a IOLstatus to a local & remote management interface of the media converter system in response to being notified of such a link status change by the monitoring function. [0027] Typically the process control function is adapted to configure N channels and to manage execution of the functional steps described above on a per channel basis for each of the N channels according to pre-defined settings. According to one embodiment, the pre-defined settings are set such that the process control function manages execution of the functional steps described above at least upon booting or rebooting of the media converter system.

[0028] The arrangement suggested above is typically also configured as a redundant system, wherein the network configuration is provided with two parallel lines, where each line comprises a first pair of link paths and a second pair of link paths, and wherein the process controlling function is further configured to switch from a first pair of link paths and a corresponding second pair of link paths of one of the lines to the first and second pair of link paths of the other line in response to

recognizing an alarm signal indicating a link status change to the IOLstatus.

[0029] According to one exemplary embodiment the process control function is adapted to manage a media converter system which has been configured as a 10GbE media converter system If such a media converter system is used the transport media used for the second pair of link paths may be provided with optical fibers which are supported by an optic SIF+ pluggable module via the HMD interface.

[0030] According to another exemplary embodiment the process control function is instead adapted to manage a media converter system which is configured as a IGbE media converter system ff such a media converter system is used the transport media used for the second pair of link paths may instead be provided with optical fibers which are supported by an optic SPF pluggable module and/ or an optic SEF+ pluggable module via the PMD interface. In case the optical fibers are supported by an optical SEF+ pluggable module, the 10GbE media converter system may be

configured to operate at any of: a limiting mode supporting one or more SEP+ lOGbase-SR IR ER type pluggable modules, and a linear mode supporting one or more SEP+ lOGbased-IRM type pluggable modules. [0031] According to another alternative embodiment, the process control function may be adapted to manage a media converter system which is configured as a IGbE media converter system M the latter case, the transport media used for the second pair of link paths may be provided with optical fibers which are supported by an optic SIF pluggable module via the HMD interface. More specifically, the transport media used for the second pair of link paths may be provided with CATό or CATB copper cables which are supported by a lOOOBase-Tpluggable module via the HMD interface. The lGbEmedia converter system may be configured to operate atany of: a forced IGbE bypass mode supporting one or more SEP lOOOGbase-SX DQO/ K40/ ZX type pluggable modules, and an auto negotiation lGbEbypass mode supporting a lOOOBase-Tpluggable module.

[0032] Tne transport media used for the first pair of link paths in any of the embodiments described above may comprise CX4 copper cables which are supported by the XAUI interface.

[0033] Further features of the methods and arrangements and its benefits suggested above can be understood from the detailed description following below.

^FOPΠON OFTHE DRAWINGS

[0034] Tne invention will now be described in more detail by way of exemplary embodiments and with reference to the accompanying drawings, in which

[0035] - Hg. 1 is a schematic overview of a network configuration comprising an IP based host system which is interconnected with an IP transport network, according to the prior art

[0036] -FIg. 2 is a schematic overview of another network configuration comprising media converter systems for the purpose of enabling for longer operating distances. [0037] -Hg. 3 is a simplified block scheme illustrating a media converter system which is configurable to execute a link status propagation process.

[0038] -Hg. 4 is a flow chart illustrating a method, according to one exemplary embodiment, for executing a pre-process at the media converter system of figure 2 and 3 for enabling successively invoking of a link status propagation processes for N channels of a line interconnecting the IPbased host system with an IP transport network

[0039] -Hg. 5 is a flow chart illustrating a method for enabling execution of a status propagation process according to one exemplary embodiment

[0040] -Hg. 6 is a simplified block scheme of an arrangement for implementation into a media converter system, such as the one described in figure 3.

DKC4 TTED DESCRIPΠON

[0041] The present document refers to a method for enabling link status propagation also in a network configuration which is provided with a media converter system, and an arrangement configured to execute the suggested method.

[0042] A typical media converter system, such as e.g. a 10GbE media converter system, will now be described in more detail with reference to figure 3.

[0043] A key component used by the media converter system is the physical layer device 319, from hereinafter referred to as the PHY, which is typically a single-chip device with a multiple sub-layer construction that follows the design requirements specified by IEEES02.3. Fbr supporting the data traffic through the fiber-optic link path, a number of multiple sub-layers are needed. These sub layers mainly consist of the sub-layer of Hiysical Media Dependent (HMD) with a par of transmitter, IMD-TX, and receiver, IMD-RX, the Physical Medium Attachment (IMA) sub-layer, and the 64F 66B Hiysical Coding Sub-layer (PCS) 304. On the other hand, the sub4ayers needed for supporting the data traffic through a CX4 copper link path mainly include the 8 B/ 1OB PCS, the 10 gigabit media independent interface (XGMH), the optional XGMII Extender Sub4ayer (XGXS), the 10 gigabit attachment unit interface (XAUD with 4 pars of transmitters, XAUI-TX and receivers, XAUI-RX As an example of hardware design, the media converter system provides both a XAUI interface 300 and a PMD interface 308, wherein the latter can be connected to the CX4 copper cable and SEP+/ SEP fiberoptic pluggable transceiver modules 107.

[0044] The XAUI TX and XAUI RX sub4ayers provide electrical functionality for transmission and reception of 4-channel serial data, typically running atthe speed of 3.125Gbps. These sub-layers include various functional components, such as e.g. clock multiplication, data serialization/ de-serialization, clock data recovery, signal amplification and differential signal driving.

[0045] The PMD TXand PMD RX sub-layers typically also provide electrical functionality for transmission and reception of 10 gigabit serial data running atthe speed of 10.3125Gbps. These sub-layers also include various functional components such as e.g. clock multiplication, data serialization/ de-serialization, clock data recovery, signal amplification and differential signal driving. The receiver equalization atthe PMD RX sub-layer may also have a built-in electric dispersion compensation (EDC) function 307 , which makes it possible for the PHY,319 not only to optimize the limiting mode with e.g. lOGBase-SR/ -IR -ERprotocols butalso to support the linear mode running e.g. atthe 10 GBa se -LRM protocol.

[0046] A XGXS PCS sub-layer 303 is responsible for coding and decoding data that will be transmitted and received on the XAUI TX and XAUI RX This functionality typically includes 8B/ 1OB encoding or decoding, randomizing and lane alignment While, the PMD/ PMA PCS sub-layer 304 is responsible for coding and decoding data that will be transmitted and received on the PMD side. The functionality includes data scrambling/ descrambling, 64B/ 66B encoding or decoding, data transitioning, synchronization, multiplexing and phase detecting, while a built-in clock multiplication unit (CIM) (not shown) can be used for achieving retiming of the XUAI TX and the HMD TX An additional first-in-first-out(ϊM)) device (not shown) is also used for 4-lane alignment and to accommodate the frequency differences of different function units, such as e.g. the XAUI clock data recovery, the HMD clock multiplier unit and the external reference clock

[0047] ϊbr supporting on-chip device configuration and control, two typical types of communication interfaces are used by the BHY device 319, i.e. the management data input/ output(MDIO) and the two-wire serial interface (EC), which in figure 3 are represented by the MDIO EC Management Interface 309 and connected to a microprocessor 310. The EC interface enables the extraction of identity information that is stored in a built-in EEFROM (not shown) of a SEP+/ SEPpluggable module 107 M addition the EC interface also provide the microprocessor 316 access to an on-tooard memory device, to EEFROM 318 and to the J/ O expender 317. The MDIO interface is mainly used for communication between the microprocessor 310 and the BHY

319. EEFROM 318 is mainly used to store inventory data, such as e.g. manufacturing information and device configurations.

[0048] An Electrically Erasable HOgrammable Read Only Memory (EEFROM) 312, accessible to the micro-processor 310 is used for installation of required firmware. Although not shown in the figure, a local & remote interface 311 is attached to the micro-process 310, for support of various tasks, such as e.g. alarm handling and firmware upgrading. The media conversion system 104 also comprises a conventional power supply (not shown).

[0049] The data flows for bidirectional transmission which can transverse through the media converter system could be summarized as following. Atone of the transmit paths, XAUI RX collects 44ane 3.125 Gbps data atthe XAUI Mterface 300 via a lane of CX4 cable and reforms the data for 10.3215 Gbps serial transmission at HVFD sublayer. On the other hand, the HVFD RX accepts 10.3125 Gbps serial HVFD data from the SEP+/ SEP interface 308 accepts a serial 10.3125 Gbps CMLdata atthe EDM interface via SFP+/ SFP and reforms the data for transmission on 3.125 Gbps 4-lane XAUITX

[0050] The introduction of FDC 307 is to overcome a strong fiber-dependence in the use of the 10Gbase-SR protocol, the so-called differential mode delay (DMD). The DMD is caused by the difference in the effective velocity of the different fiber modes caused by imperfections in the index profiles of the fibers. Because of DMD, the conventional lOGbps serial transmission over legacy multimode fibers (MMF) is severely limited. Fbr instance, the lOGbase-SRbased optical modules support only 26 m of MMF with the modal bandwidth of 160/ 500 MHz.km, i.e. the so-called FDDI- grade type, 33 m of MMF with the modal bandwidth of 200/ 500 MHz.km, i.e. the so-called OMl type, 82m of MMF with the modal bandwidth of 500/ 500 MHz.km, i.e. the so-called OM2 type, and 300 m of MMF with the modal bandwidth of

1500/ 500, i.e. the so-called OM3 type, respectively. The problem becomes more complex because the DMD can also vary with time due to fiber movement, temperature variation and other effects that change the optical power distribution across the mode group.

[0051] The MDIO management interface 309 specified by IEEEB 02.3 clause 45 provides a simple serial management interface between the PHY 319 and the external micro-processor 310. With the help of MDIO, the status of all MDIO manageable devices (MMD) built in different sub-layers of PHY 319 can be accessed, monitored and controlled by the micro-processor 310. Fbr example, the MMD device addresses 1, 3 and 4 are well-specified to the PMD, PCS and XAUI sub-layers in clause 45, respectively. Fbr each device, a number of 164a it registers can be defined for different purposes, mainly to read the device status and to execute the control and/ or test functions of on-chip devices. Fbr each bit of the register, a specific function can be assigned. It is to be understood that, for getting a specific status and/ or executing a specific function for the device, the combination of a number of bits from one or more devices may be used simultaneously. [0052] Fbr supporting a process of link status propagation, the most interesting registers would be the status registers that define the operating modes, such as e.g. the limiting, linear, the forced IG bypass, auto negotiation IG bypass modes, the link status registers for both XAUI-RX and H)M-RX receivers, and the control registers for both the XAUI-TX and PDM-TX transmitters.

[0053] A process for enabling link status propagation also in a network comprising media converter systems, such as e.g. the 10GbE media converter system will now be described in more detail with reference to figures 4 and 5. The suggested link status propagation process may be divided into two processes, namely a preparatory pre-process and a main-process.

[0054] A pre-process according to one exemplary embodiment is illustrated with the flow chart of figure 4. The pre-process is mainly used for enabling or disabling a new process of link status propagation for an invidious channel P₁, where, i=l to N, and where N is the total number of channels supported by the media converter systems. The pre-process is also used for invoking the main-process, which adapted to provide for link status propagation to support the operation of the PHY whenever required.

[0055] After starting or rebooting the media converter system as indicated in a step 401, default configurations for on-chip devices and default values for registers are downloaded to the PHY, as indicated in a next step 402, after which a number of well- defined ordinary processes, including a device initialization and a device self-test, are executed, as indicated in another step 403. Subsequent to these preparatory steps the media converter system is ready for setting up the links for both link paths which are supported by the media converter system, i.e. the CX4 copper link and fiberoptic link paths.

[0056] As indicated with steps 408,409,404 and 405, for each channel i, the pre-process determines if there is a need to invoke and run the link status propagation main-process according to pre-defined settings, as indicated with a step 406, or if the process shall be disabled, as indicated with another, alternative step 407 . This process is repeated for all N channels, after which the pre-process is terminated, as indicated with a final step 410. Since a number of different types of IHY may be used by the same media converter system, the pre-process also check the IHY used by the each specific channel P₁.

[0057] Hg.5 illustrates a main-process thatperforms a process of link status propagation across the media converter system, according to one exemplary embodiment

[0058] The main process is initiated by determining the operating mode that is pre-defined by the operator for a channel, P₁. , where, j=l ,2,..,M-l,M and where M is the number of modes, as indicated with a step 501. The modes are typically accessible by interrogating a register of operating mode, as indicate with a next step 502. The main process may thus be repeatedly executed for each of the N channels.

[0059] By way of example, four different types of operating modes may be predefined, for a 10GbE configuration, namely the lOGbElimiting mode, the 10GbE linear mode, the forced lGbEbypass mode and the auto negotiation lGbEbypass mode.

[0060] It is to be understood that, for a specific operating mode, specific sets of status and control registers are usually defined by the vendor of the PHY. Thus, one has to invoke operating mode-dependent registers for controlling all key devices, such as e.g. XAUI-EK₁ (j), PMD-EK₁ (j) XAUHX₁ (j) and PMDOX₁ (j).

[0061] For setting up both links, the transmitters of the PHY, i.e. XAUITX₁(J) and PMDTX₁(J), have to be switched ON so that a built-in link test function can be executed. This is indicated with another step 503. In this step, the link path between the media converter system and the host system, which is typically a CX4 copper link path, as well as the fiber-optic link path of the opposite side of the media converter system are tested and the links among them are setup if no failures in the link paths have been found.

[0062] M the described embodiment, a monitoring process, which is typically configured as a real-time monitoring process, is used to monitor the link statuses for both link paths. Following the flow chart of figure 5, the process first determines the status of the CX4 copper link path by reading the XMJI-RX₁ (j) link status register, for channel P₁ , as indicated with a step 504.

[0063] I^" a loss of link (IDI) occurs, such as the failure of CX4 cable or the failure of the transmitter of the host system, the process will turn off the PMD-TX₁ (j) of the PHY for the channel P₁ in the media converter system if it is on, as indicated with a step 505. In such a way, the link status is propagated across the media converter system toward the remote partner, and the alarm signal is also sent to the local/ remote management interfaces and the alarm signal list is also updated correspondingly, as indicated in step 506. The information of the alarm signal is stored in the EEFROM so that the alarm information can be fetched whenever it is needed. On the other hand however, if a IOLproblem is instead registered in the CX copper link path, the status change of the XAUI-RX₁ (j) receiver will be found by the real-time monitoring process. Thus, the PMD-TX. (j) will be automatically turned ON if it is found to be off, as indicated with another step 507, and the alarm signal list will also be updated correspondingly, as indicated with a subsequent step 508.

[0064] The similar procedures will also be applied to the fiber-optic link path, such that the changes of link status will be monitored in real-time by reading the status register of PMD-RX₁ (j), as indicated with another step 509. According to the

determined link status, the corresponding operation of switching OI^or turning ON the XAUI-TX. (j) on the mutual side of the PHY will also be taken, according to step 511 or 510, respectively. Subsequent to an enabling of the XAUI-TX₁ (j), the alarm signal list is updated, as indicated with a step 512, while an alarm is sent, in addition to updating the alarm signal list, as indicated in another step 513, if the XAUI-TX₁ (j) is instead disabled. Fbr speeding up the process, the status registers of XAUI-RX₁ (j) and HMD-RX₁ (j) will typically always be checked before taking the action to operate the XAUI-TX₁ (j) or the HVIIKIX₁ (j) devices. The whole process will typically be carried on continuously with a time set for each iteration cycle in the order of a few ms.

[0065] It is well-kno wn that the time fo r switching O N/ O FF so me pluggable transceiver modules which are compatible with the media converter system may be significantly longer. The operating time could for example be as long as a few hundreds of ms for an SFP lOOOBase-Tpluggable transceiver module. Thus, for the stabilization of the process and the matching of the operating time of a module, an opera ting mode dependent time delay parameter, i.e. Delay Εj), as indicated with respective steps 514 and 515 can be introduced for automatic adjustment of the time in the described iteration cycle.

[0066] An arrangement for performing a link status propagation process at a media converter system 104, 104' according to the embodiments described above may be configured according to the simplified block scheme of figure 6 where a media converter system 104,104' is provided with an arrangement 600 e.g. by way of adapting the micro-processor 310 of figure 3, or any other processing functionality arranged on the media converter system 104,104'. According to figure 6, the arrangement 600 is provided with a function for controlling the suggested process, which is here referred to as a process controlling function 401. The process controlling function is configured to control a link status propagation process by interacting with functionality, here implemented as an enabling/ disabling function 602, which is configured to enable or disable a respective XAUI-TXor a HMDTX transmitter whenever required. The process controlling function 601 typically controls the enabling/ disabling function 602 in response to the re suit fro m a monitoring function 603, which is configured to monitor the status of the XAUI-RXand HMDRX receivers, by monitoring relevant link status registers 604, which are accessible by the monitoring function 603. The suggested process controlling function 601is also configured to activate an alarm generating function 605, such that an alarm can be sent, and such that an alarm signal list 606 can be updated accordingly in response to recognizing that a X^m-TX or IMD-TX transmitter need to be enabled or disabled.

[0067] While the invention has been described with reference to specific exemplary embodiments, such as e.g. 10GbE configurations, the description is generally only intended to illustrate the inventive concept and should not be taken as limiting the scope of the invention, which is defined by the appended claims. It is to be understood that the naming and combination of functional units is only exemplary and that other alternative combinations of functional units which provide corresponding functionality which fall within the inventive scope of this document may be used to replace the ones used in the given examples.

ABBREVIATIONS

EDC Electric Dispersion Compensation

EEFROM Electrically Erasable HOgrammable Itead Only Memory

HFO First-M-FirstOut

GbE Gigabyte Ethernet

EC TWo -wire serial Interface

IP Internet Protocol

IOL Lass Of link

PHY Physical layer Device

SMF Single Mode optical Fibers

MDIO Management Data Input/ Output

MMD MDIO Manageable Device

MMF Multi Mode Fiber

PCS Physical Coding Sub-layer

PMA Physical Medium Attachment

PMD Physical Media Dependent

XGXS XGMH extender Sub4ayer

Claims

CIAMS

1. A method of supporting link status propagation in a network

configuration, comprising a media converter system (104;104') interconnecting an IPbased host system (100) with an IPbased transport network (102), where the IPbased host system (100) is connected to the media converter system (104;104') via a first pair of link paths (105a/ 106b;105a7 106b') and the IP based transport network (102) is connected to the media converter system (104;104') via a second pair of link paths (106a/ 106b;106a7 106b'), characterized in that

a link status change atone of said link paths (105a;105a'; 106b;106b') is automatically propagated across the media converter system (104;104') to the opposite link path (105a;105a';106b;016b') by enabling (507,510) a corresponding transmitter (PMD-TX; XAUI-TX) in case it is disabled or by disabling (505,511) a corresponding transmitter (PMD-TX, XAUI-TX) in case it is enabled.

2. A method according to claim 1, comprising the steps of :

- monitoring (504;509) respective link statuses of the first and the second pair of link paths in order to register link status changes;

- disabling (505,511) said corresponding transmitter (PMDTX; XAUI-TX) in case it is enabled and in case a link status change to a loss of link (IDI) status of said link paths is recognized during said monitoring, and

- enabling (507;510) said corresponding transmitter (PMDTX; XAUI-TX) in case it is disabled and in case a link status change from a IOLstatus of one of said link paths is recognized during said monitoring.

3. A method according to claim 2, wherein the monitoring step (603) comprises monitoring transmitter link status registers (604) of a physical layer device (IHY) of said media converter system (104;104').

4. A method according to claim 2 or 3, wherein the enabling/ disabling steps (505;511) comprise the further step of updating (506;508;512;513) an alarm signal list according to a monitored link status change.

5. A method according to claim 4, comprising the further step of sending an alarm signal indicating a monitored link status change to a IOLstatus to a local & remote management interface (311 ) of said media converter system

(104;104') in case atleastone of said transmitters has been disabled.

6. A method according to any of claims 1-5, wherein the network

configuration comprises two parallel lines, each comprising a first pair of link paths (105a/ 105b;105aV 105b') and a second pair of link paths

(106a/ 106b;106aV 106b'), the method comprising the further step of switching from a first pair of link paths and a corresponding second pair of link paths of one of said lines to the first and second pair of link paths of the other line in response to recognizing an alarm signal indicating a link status change to the IOLstatus.

7. A method according to any of the preceding claims, wherein said media converter system (104,104') is supporting N channels and wherein said method steps are executable (406) on a per channel basis for each of said N channels according to pre-defined settings.

8. A method according to claim 7, wherein said method steps are

executable (406) on a per channel basis for each of said N channels according to pre-defined settings upon booting or rebooting (401) said media converter system (104,104').

9. An arrangement(600) in a media converter system (104;104') capable of supporting link status propagation in a network configuration, comprising an IP based host system (100) and an IPbased transport system (102), wherein the media converter system (104;104') is arranged such Ihatitis interconnecting said IPbased host system (100) with said IPbased remote link partner (102) , where the IPbased host system (100) is connected to the media converter system (104;104') via a first pair of link paths (105a/ 105b;105aV 105b')) and the IPbased host system (100) is connected to the media converter system (104;104') via a second pair of link paths (106a/ 106b;106a7 106b') , characterized by:

- a process controlling function (601) configured to enable for a link status change occurring atone of said link paths (105a;105a';106b; 106b') to automatically propagate across the media converter system (104;104') to the opposite link path (105a;105a';106b; 106b') by instructing an

enabling/ disabling function (602) to enable a corresponding transmitter (PMD- TX; XAUI-TX,) in case it is disabled or to disable a corresponding transmitter (PMD-TX; XAUI-TX) in case it is enabled, in response to recognizing that said link status change has occurred.

10. An arrangement (600) according to claim 9, further comprising:

- a monitoring function (603) configured to monitor a respective link status of the firstand the second pair of link paths (105a;105a';106b;106b'), such that link status changes can be recognized, wherein said enabling/ disabling function (602) is configured to:

- disable said corresponding transmitter (PMD-TX; XAUI-TX) in case it is enabled, in response to being notified by said monitoring function (603) of a link status change to a loss of link (IDI) status, and - enable said corresponding transmitter (H)M-TX; XAUI-TX) in case it is disabled, in response to being notified by said monitoring function (603) of a link status change from a IOLstatus.

11. An arrangement (600) according to claim 10, wherein the monitoring function (603) is configured to execute said monitoring in real-time.

12. An arrangement (600) according to claim 10 or 11, further comprising receiver link status registers (604), wherein the monitoring function (603) is configured to execute said monitoring steps by monitoring the respective receiver (H)M-RX; XAUI-RX) link status registers (604) of a physical layer device (PHY;319) of said media converter system (104;104').

13. An arrangement (600) according to claim 10, 11 or 12, further

comprising an alarm generating function (605) configured to update an alarm signal list (606) according to a monitored link status change recognized by the monitoring function (603).

14. An arrangement (600) according to claim 13, wherein the alarm

generating function (605) is further configured to forward an alarm signal indicating a monitored link status change to a IOLstatus to a local & remote management interface (311) of said media converter system (104;104') in response to being notified of a such a link status change by the monitoring function (603).

15. An arrangement (600) according to any of claims 9-14, wherein the process control function (601) is adapted to configure N channels and to manage execution of said functional steps on a per channel basis for each of said N channels according to pre-defined settings.

16. An arrangement (600) according to claim 15, wherein the process control function (601) is configured to manage execution of said functional steps upon booting or rebooting of said media converter system (104;104').

17. An arrangement (600) according to any of claims 9-16, wherein the

network configuration comprises two parallel lines, each comprising a first pair of link paths (105a/ 105b;105aV 105b') and a second pair of link paths (106a/ 106b;106aV 106b'), and wherein the process controlling function (601) is further configured to switch from a first pair of link paths and a corresponding second pair of link paths of one of said lines to the first and second pair of link paths of the other line in response to recognizing an alarm signal indicating a link status change to the IOLstatus.

18. An arrangement (600) according to any of claims 9-17, wherein the

process control function (601) is adapted to manage a media converter system (104;104') which is configured as a lOGbEmedia converter system

19. An arrangement (600) according to claim 18, wherein the transport

media used for the second pair of link paths (106a/ 106b;106aV 106b') comprises optical fibers which are supported by an optic SIF+ pluggable module via the HMD interface 308.

20. An arrangement (600) according to claim 19, wherein said 10GbE

media converter system is configured to operate at any of: a limiting mode supporting one or more SEP+ lOGbase-SR IR ER type pluggable modules , and a linear mode supporting one or more SEP+ lOGbased-IRM type pluggable modules.

21. An arrangement (600) according to any of claims 9-17, wherein the process control function (601) is adapted to manage a media converter system (104; 104') which is configured as a IGbE media converter system.

22. An arrangement (600) according to claim 21, wherein the transport media used for the second pair of link paths (106a/ 106b;106aV 106b') comprises optical fibers which are supported by an optic SIF pluggable module via the HMD interface 308.

23. An arrangement (600) according to claim 21, wherein the transport media used for the second pair of link paths (106a/ 106b;106aV 106b') comprises any of CATo or CAT6 copper cables which are supported by a lOOOBase-Tpluggable module via the HVLD interface 308.

24. An arrangement (600) according to any of claims 21-23, wherein said IGbE media converter system is configured to operate at any of: a forced IGbE bypass mode supporting one or more SEP lOOOGbase-

SX/ IXlO/ 1X40/ ZX type pluggable modules, and an auto negotiation IGbE bypass mode supporting a lOOOBase-Tpluggable module.

25. An arrangement (600) according to any of claims 18- 24, wherein the transport media used for the first pair of link paths (105a/ 105b;105aV 105b') comprises CX4 copper cables which are supported by the XAUI interface (300).