RU2417530C2 - System and method of monitoring end nodes using ethernet connectivity fault management (cfm) in access network - Google Patents

Abstract

FIELD: information technology.

SUBSTANCE: system and method of monitoring end nodes uses Ethernet connectivity fault management (CFM) in an access network. In one version, a broadband access server (BRAS) is operable to generate an Ethernet CFM frame that includes a query message with respect to a particular end node. An interworking function (IWF) entity associated with an access node that services the particular end node is operable to interpret the Ethernet CFM frame and construct a corresponding query message in a native protocol compatible with the particular end node. Upon receiving a reply message from the particular end node, the IWF entity constructs a suitable reply Ethernet CFM frame for transmission to the BRAS, wherein the reply Ethernet CFM frame includes a response corresponding to the reply message from the end node.

EFFECT: improved monitoring of end nodes.

21 cl, 4 dwg

Description

PRIORITY ACCORDING TO 35 U.S.C. § 119 (e) and 37 C.F.R. § 1.78

This unconditional priority of the claims is based on the following provisional patent application (s) of the United States: (i) ″ INTERWORKING BETWEEN METRO ETHERNET AND ACCESS OAM, ″ (Interaction between the ETHERNET metro network and OAM access) Application No: 60/643 945, filed January 14, 2005 on behalf of: Kamakshi Sridhar, Sven Oghhe, Martin Petrus Joseph Wissers and Atiyah Suheil; and (ii) ″ BROADBAND ACCESS END-TO-END CONNECTIVITY TESTING WITH CFM OAM IN THE ACCESS NETWORK ″ (Broadband access when testing endpoints using CFM OAM on an access network) Application No. 60/656 487, filed February 25, 2005 on behalf of: Kamakshi Sridhar, Sven Oghhe, Martin Petrus Joseph Wissers and Atiyah Suheil, each of which is hereby incorporated by reference.

State of the art

FIELD OF THE INVENTION

The present invention, in General, relates to access networks that integrate a set of local Ethernet networks. More specifically and without any limitation, the present invention is directed to a system and method for monitoring end nodes using Ethernet Connectivity Error Management (CFM) functionality.

Description of the Related Art

Current access network solutions using the technology of the first / last point have significant drawbacks from the point of view of subscribers, starting from bottlenecks in the characteristics, availability of conditions for a fixed bandwidth, limited extensibility, lack of flexibility and complexity of provision, and to quality of service (QoS) problems the entire line and structure of high costs. The use of rigid, simple Ethernet technology at the first stage promises to dramatically change the access network, since it was made against the background of enterprise networks, where it began as a transport technology of local area networks (LAN), used for communication between computers and networks. How Ethernet access technology offers three significant advantages over previous technologies of the first stage: (i) transport with future validation of applications for data, video and voice data; (ii) cost-effective infrastructure for information services; and (iii) a simple, globally accepted standard that will guarantee interoperability.

To adapt Ethernet technology to a carrier-class service environment, various standards are being developed that aim to provide advanced capabilities in the Administrative Data Management (OAM) format (also referred to as connectivity and error management or Ethernet CFM) across the network from one endpoint to another. Since the end-to-end network service environment ″ typically consists of many diverse constituent networks (for example, metro access networks and core networks using a wide variety of technologies) that may belong to different organizations, network operators and service providers, Ethernet CFM is envisaged as a hierarchical multilevel domain space in which certain CFM domains (or, which is synonymous, OAM domains) are defined in accordance with the infrastructure and provision of boiling networks. In particular, two standards, IEEE 802.1ag and the ITU-T project, Y.17ethoam Recommendation, incorporated herein by reference, which are specific to the integrated Ethernet CFM, define a client-level domain at the highest hierarchy level that contains one or more provider domains (occupying an intermediate level), each of which in turn contains one or more operator domains located at a lower hierarchical level. Through standardization, the CFM domain space can be divided into a number of levels, for example 8 levels, with each domain corresponding to a particular level in which the domain is defined in terms of what is referred to as points of passage. In the context of the IEEA 802 specification program package, the points of entry are new objects contained in ″ interfaces ″ and ″ ports ″ of Media Access Control (MAC), as defined in the documentation for the relevant standards. The port can implement numerous passage points of various types. Checkpoints are commonly referred to as ETH checkpoints and are associated either with the ″ Maintenance End Point ”or MEP layout function, or the ″ Maintenance Intermediate Point ″ or MIP layout function. Typically, the MEP layout functions are located on the edge of the CFM domain, while the MIP layout functions are located within the domain and remain visible to the MEP border functions. A node can perform a MIP function, a MEP function, or both, depending on how the domains are configured. Accordingly, the terms ″ MEP node ″ and ″ MIP node ″ can be used to broadly define the functionality of a node that implements the MEP layout function, and the functionality of a node that implements the MIP function, respectively, although they can be defined on one single node. Whereas ″ MEP nodes ″ are used by system administrators to initiate and monitor CFM activities (by issuing appropriate CFM frames), ″ MIP nodes ’passively receive and respond to CFM flows initiated by ″ MEP nodes ″.

A CFM domain having one or more MIP nodes can be surrounded by multiple MEP nodes. In order for these CFM frame streams to be filtered accordingly, so that they are processed only by the nodes of the assigned domain, the MEP / MIP set in the Ethernet CFM network is configured accordingly. For example, in accordance with existing standards, an integer value can be provided to indicate a specific domain level in the Ethernet CFM hierarchy.

In addition, standards are also indicated for expanding the service delivery technology, which allows initialization of virtual local area networks (VLANs) at the top of the data layer (i.e. Layer-2 or L2) of an Ethernet network to add flexibility, versatility and security to the CFM network. VLANs can be defined at various levels, such as client, provider, etc., and can include any number of non-overlapping CFM domains. Service frame fields preceded by ″ C- ″, such as a C-VLAN identifier, refer to fields created by the client. Similarly, service frame fields preceded by ″ S- ″ (for example, an S-VLAN ID) refer to fields added by the service provider. By implementing VLANs, Ethernet CFM from one endpoint to another can be broken down into many service implementations while maintaining multiple C-VLAN subscribers in which traffic in a given VLAN is invisible to end host computers belonging to another VLAN, thus shortening the broadcast domain.

Although the Ethernet CFM architecture, as it is currently standardized, provides an impressive structure for addressing Ethernet CFM from one endpoint to another at any level of the hierarchy, a number of problems remain unresolved. A particular concern is endpoint control, where the access links that connect endpoints (i.e., client network sites) to the metro provider network can operate in a non-802.lag environment, while the metro provider network can contain an 802.lag-compatible network .

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to a control method suitable for working with an access network for testing, querying or any other control of end nodes using Ethernet CFM in an access network. An access network comprises at least one access node connected to one or more end nodes and a broadband access server (BRAS) connected to a regional Ethernet network. In one embodiment, the method comprises: creating, using BRAS, an Ethernet CFM frame routed to an access node associated with them, wherein the Ethernet CFM frame contains a request message for a specific end node served by the access node; Interpreting an Ethernet CFM frame using an interworking function (IWF) object associated with an access node and embedding the corresponding request message in its own protocol compatible with a particular end node; the reaction to the corresponding request message from the access node by creating a specific end node of the response message in the same proprietary protocol or another proprietary protocol directed to the access node; interpreting the response message by the IWF and embedding an Ethernet CFM response frame containing a response that corresponds to the response message from the end node; and transmitting the Ethernet CFM response frame to BRAS.

In another aspect, the present invention is directed to a monitoring system associated with an access network, wherein the access network comprises at least one access node connected to one or more end nodes and a BRAS node connected to a regional Ethernet network. In one embodiment, the system comprises: means associated with BRAS to create an Ethernet CFM frame directed to an access node associated therewith, in which an Ethernet CFM frame contains a request message regarding a specific end node served by the access node; IWF means associated with an access node for interpreting an Ethernet CFM frame and embedding the corresponding request messages in a proprietary protocol compatible with a particular end node; means associated with a particular end node capable of responding to a corresponding request message from the access node to create a response message in the same native protocol or in another native protocol directed to the access node in which the IWF acts to interpret the response message in Native protocol and embed an Ethernet CFM response frame containing a response that corresponds to a response message from the end node in the Ethernet CFM response frame for transmission to BRAS.

In yet another aspect, the present invention is directed to a network element operating in an access network, comprising: a logic structure adapted to interpret an Ethernet CFM frame received from a BRAS located in an access network, an Ethernet CFM frame containing a request message regarding an end node, served by a network element operating as an access node; a logical structure configured to create a corresponding request message in a proprietary protocol compatible with the end node, a corresponding request message based on a request message in an Ethernet CFM frame; a logical structure configured to interpret a response message provided to end nodes responding to a corresponding request message, a response message compatible with the same proprietary protocol or another proprietary protocol; and a logical structure configured to embed an Ethernet CFM response frame containing a response that corresponds to a response message received from the end node in the Ethernet CFM response message for transmission to BRAS.

Brief Description of the Drawings

The accompanying drawings form an integral part of the detailed description to demonstrate one or more currently preferred embodiments of the present invention. Various advantages and features of the invention should become apparent from the following detailed description, taken in conjunction with the appended claims and with reference to the accompanying drawings, in which:

Figure 1 is an example of building a network containing an access part with an Ethernet connection, in which the disclosure of the present patent may be implemented;

FIG. 2 is an example of a circuit according to one embodiment for performing port testing using Ethernet CFM in the construction of the network shown in FIG. 1;

3A and 3B are examples of Ethernet CFM frames suitable for performing port testing in accordance with one embodiment of the present invention.

Detailed Description of Drawings

Embodiments of the invention will now be described with respect to various examples of how the invention can best be implemented and used. The same reference numbers are used throughout the description and several types of drawings, in which similar or corresponding parts are indicated and various elements are not necessarily drawn to scale. Turning now to the drawings, and in particular to FIG. 1, an example of building a network 100 is shown comprising an Ethernet-connected access part 104, in which an embodiment of the present patent can be disclosed to control an end node using Ethernet CFM message transmission. Preferably, Ethernet CFM messaging is supported in a band on a data path in an access network. A regional or Ethernet metro network 102 containing one or more routers 116 and one or more Authentication, Authorization and Accounting (AAA) servers 118 are operatively connected to access network part 104. In a typical deployment, the infrastructure of the access network 104 may include one or more access nodes 108 that can connect through an Ethernet switch 112 to a broadband access server (BRAS) node 114. For the purposes of the disclosure of this patent, the access network 104 can be formed by any type of network technology as a whole (e.g., digital subscriber line (xDSL), Ethernet in First Mile (EFM), asynchronous data transfer (ATM), etc.), which can be implemented using various physical transport media (such as radio, wireless, fully optical, electron-optical, etc.). Accordingly, any person skilled in the art should recognize that the access network infrastructure may contain appropriate access node elements (for example, one or more elements of a DSL or DSLAM access multiplexer), depending on the particular deployment, and in which the elements are suitably adapted to include to Ethernet through other Ethernet-compatible elements, such as the Ethernet switch 112 and BRAS 114.

Regardless of the type of access network technology, access node 108 is configured to service one or more end nodes 106, typically located in a client’s premises. End nodes 106 may contain various equipment, such as DSL modems, network termination (NT) modules, resident gateway (RG) modules, etc., at least in part due to differences in basic network access technologies. For the purposes of this disclosure, end nodes 106 may also commonly be referred to as ″ ports ″, which can be monitored or requested by the corresponding element of access node 108 using appropriate OAM messaging in one or more ″ native ″ protocols. Depending on the access network technology, for example, proprietary protocols compatible with end nodes 106 and access node 108 may be suitable for working with EFM OAM messages, ATM OAM messages, and the like.

An interworking function (IWF) object 110 is advantageously provided in connection with an access node 108, integrating with it or otherwise, to implement Ethernet CFM functionality with respect to one or more end nodes 106. Essentially, the IWF 110 is configured with the ability to work in the OAM representative mode, which defines the MEP node within the Ethernet CFM domain containing other BRAS 114 MEP objects, whereby a service channel between the control node, for example, BRAS, can be organized within the bandwidth 114, and the access node and the attached IWF entity. In general, BRAS 114 may be configured to respond to a BRAS control action, such as a request 120 by the AAA server 118 to initiate a CFM port test / request with respect to monitoring a specific end node (e.g., feedback loop). In operation, the IWF 110 enables bidirectional interpretation of the protocol, so that when the control node issues an Ethernet CFM frame in accordance with a port test request, the logic structure 122 of the IWF 110 is configured to interpret an Ethernet CFM frame that contains a corresponding request message for a specific end the node identified within the frame. A particular end node may contain a physical port or a logical port, for example, associated with a permanent virtual circuit or connection (PVC). Another logical structure 124 is configured to embed the corresponding request message in its own protocol compatible with the identified end node. When an IWF object 110 is configured as a MEP node within an Ethernet CFM domain defined on a VLAN, the IWF object 110 contains an appropriate logic to resolve port addressing, regardless of whether the VLAN uses a 1: 1 addressing scheme or an N: l port addressing scheme . The accompanying logical structure 126 is configured to interpret the response message provided by the end node responding to the corresponding request message in its own protocol. Another logical structure 128 is configured to create an Ethernet CFM response frame containing a response that corresponds to a response message received from the end node that the Ethernet CFM response frame transports back to the control node, that is, to BRAS 114 that initialized the test feedback loop / port request.

With reference to the foregoing, the IWF 110 may be integrated within an access node 108 in which various logical structures configured to implement the functionality set forth above may be combined in any combination in software, firmware, program code, etc. .d. Regardless of the exact implementation, one skilled in the art should recognize that the initialization of the IWF 110 in connection with the access node 108 supports another service channel that follows a data path where technicians can initialize port control using the feedback loop at the appropriate point access, for example, BRAS 114. To ensure continuous interoperability between Ethernet CFM and an existing OAM access network (such as, for example, ATM OAM, EFM OAM, etc.), functionality IWF 110 may be implemented within a number of limitations. For example, you might want the IWF logic to be compatible with current as well as future DSL modem technologies. Also, when Ethernet CFM domains containing an access network are defined via VLANs, IWF logic may be needed to support multiple VLAN address assignment schemes (i.e., VLANs 1: 1 and N: l). In addition, the IWF functionality should preferably be capable of bridge and routed encapsulation (i.e. tunneling) on the path of the access line in question. Examples of bridge encapsulation implementations may include Internet Protocol (IP) / Point-to-Point Protocol over Ethernet (PPPoE) / Eth / ATM / DSL, as well as IP / ETH / ATM / DSL. Representative routed encapsulation embodiments include, for example, IP / PPP / ATM / DSL and IP / ATM / DSL.

FIG. 2 shows an example of a port control circuit 200 according to one embodiment suitable for operating with the network building 100 described above with reference to FIG. 1. An intelligent centralized control node, for example, an AAA server node 118 located in a regional Ethernet metro network, is configured to initiate a port test / control request message in the BRAS direction in the access network associated with it (block 202). In response, BRAS creates a corresponding Ethernet CFM frame containing a request in the direction of a specific AN / IWF in the access network (block 204). The IWF logic associated with the AN node interprets the CFM message and generates a corresponding test / request message (for example, port status) in its own protocol, routed to the port or to the end node identified in the CFM frame. After receiving the request message in its own protocol, the end node creates a response (for example, the port is valid, the port is not valid, there is no answer, an error response, an incorrect answer, etc.) and sends it to the AN node (block 208) or in the same own protocol, or in another proprietary protocol. After that, the IWF associated with the AN interprets the test / request response from the end port and creates the corresponding Ethernet CFM frame forwarded to BRAS (block 210). In response to the CFM response frame from the AN, the BRAS generates a port test response and forwards it forward to the intelligent centralized management server (block 212).

In order to support the Ethernet CFM service channel through the corresponding IWF functionality in the access network, a new Ethernet CFM frame is introduced in which the corresponding OpCode field of operation code defines the type of port request / test message (e.g. port feedback loop) and the payload carries related content with request messages and responses. In one direction, an Ethernet CFM frame is for an AN / IWF that serves a specific endpoint identified in a payload. For example, a payload may type Type / Length / Value (TLV) encoding to indicate the end node (e.g., DSL port / shelf / VPI / VCI) among other parameters, as will be described below . Alternatively, the payload could use the Link Access Procedure on the D Channel (LAPD) mechanism, which creates a bitstream with respect to a specific destination. Regardless of implementation, it should be understood that the semantics of testing / port request and response can preferably be contained within the payload using appropriate TLV coding.

3A and 3B show examples of Ethernet CFM frames suitable for performing port testing in accordance with one embodiment of the present invention. Reference numeral 300A refers to an Ethernet CFM frame created by a BRAS with respect to a specific end node indicated in a Circuit field 302. The Operation Code (OpCode) field 304 indicates the type of port test message. The EtherType field 306 identifies the frame as a CFM frame. Depending on the addressing scheme, both an S-VLAN identifier field 308 and an EtherType VLAN field 310 can be provided. The Source Address (SA) field 312 identifies the MAC BRAS, and the Destination Address (DA) field 314 identifies the MAC address of the AN / IWF.

The 300M Ethernet CFM response frame contains similar fields, for example, an EtherType VLAN field 330, an S-VLAN ID field 328, and an EtherType OAM / CFM field 326. In this case, however, DA field 334 identifies BRAS and SA, field 332 identifies an AN / IWF that has received a response message from an end node responding to a test / request message from BRAS. The OpCode field 324 indicates the type of response message for port testing. The port test results are contained in the Circuit Status field 322, which provides appropriate TLV coding for this. For example, it may indicate ″ G.992.1 up ″, ″ 1.610 LB down ″ or ″ 802.3ah Loopback up ″, etc. Additionally, although not specifically shown, more detailed information (eg, ″ 802.lag MEP Address ″) can also be provided in the 300V Ethernet CFM 300B response frame via an optional TLV.

Admittedly, although the embodiments of frames 300A and 300B seem to depict the corresponding OpCode and 324 fields at the same level as the corresponding Ethertype fields 306 and 326, the OpCode fields are actually at a different level in the sense that these OpCode fields are used to introduce an additional communication channel between the BRAS and the DSLAM, in which the contents of the PDU (i.e., the OAM payload) defines one or more messages, such as port test messages or port test response messages described above. When a TLV coding scheme is used, the TLV-TYPE field is configured to carry a port test message code or a port test response code, the TLV-LENGTH field is capable of carrying a TLV length, and the TLV-VARIABLE field is capable of transferring an identifier 302 of an end a node or Circuit in a suitable format, for example, in the format of a DSL port / shelf / VPI / VCI or C-VLAN identifier or in another format.

Regardless of the VLAN port addressing scheme, the AN / IWF is configured to map the port identifier used by BRAS to a unique physical / logical entity (i.e., end node) on the subscriber side. In the 1: 1 VLAN port addressing scheme, each end user is uniquely identified by an entry (C-VLAN ID; S-VLAN ID) that identifies a specific port. Whereas the S-VLAN ID 308 308 is provided as part of the header of the Ethernet CFM frame, the C-VLAN ID can be encoded as the Circuit TLV ID 302, as described above. In the VLAN N: port addressing scheme, the end ports are not uniquely identified by a record (C-VLAN ID; S-VLAN ID), because users do not have any C-VLAN ID. Rather, the end ports are differentiated only through the Circuit identifier. Accordingly, in a 1: 1 scheme, a TLV-VARIABLE can carry a C-VLAN identifier as a Circuit or as an end node identifier, whereas in an N: l VLAN addressing scheme, a DSL port / shelf / VPI / VCI identifier could be used as a circuit identifier / end node. BRAS can, therefore, provide additional address information within the payload of the port test message, for example, using Circuit TLV identifier encoding similar to the DSL port authentication methods specified for the Dynamic Host Control Protocol (DHCP) and PPPOE.

Based on the foregoing detailed description, it should be understood that the disclosure of representative embodiments of the present patent advantageously provides an efficient scheme for expanding Ethernet CFM capabilities to end nodes in an access network. For example, testing and monitoring connectivity can be done from a central access point (e.g., BRAS), which is independent of any out-of-band element management system (EMS) deployed to test DSLAM nodes in an access network. Additionally, CFM procedures for monitoring the end node, as provided for in accordance with the description given here, can preferably be implemented regardless of access link technology. Those skilled in the art will recognize that the embodiments set forth herein may be practiced in a form containing software, hardware or firmware, or any combination thereof associated with the respective network equipment.

Although the invention has been described with respect to some examples of embodiments, it should be understood that the forms of the shown and described invention should be considered only as examples of embodiments. Accordingly, various changes, substitutions and modifications can be implemented without departing from the scope and essence of the invention, as defined by the attached claims.

Claims (21)

1. A method for monitoring end nodes suitable for working with an access network, wherein said access network includes at least one access node associated with one or more end nodes, and a broadband access server (BRAS) connected to the authentication server, authorization and accounting (AAA) in a regional network compatible with 802.lag Ethernet, containing the stages in which:
respond to the port request message from the AAA server in the regional Ethernet network, create, using the aforementioned BRAS frame, an Ethernet CFM directed to the access node, said CFM frame including a field that defines the type of request message and useful data, which include identification a specific end node served by said access node;
interpreting said CFM frame using an interworking function (IWF) object associated with said access node, and embedding the corresponding request message in a proprietary protocol compatible with said specific end node; in response to said corresponding request message, a response message is generated using said end node in said own protocol and sent to said access node;
interpreting said response message with said IWF and embedding an Ethernet CFM response frame including a response that corresponds to said response message; and
transmitting said Ethernet CFM response frame to said BRAS; and
Responding to the Ethernet CFM response frame, they create a response using BRAS to the action from the AAA server and transmit the port request response to the AAA server. 2. The control method suitable for working with the access network according to claim 1, wherein said IWF associated with said access node is defined as a final service center (MEP), which is part of an Ethernet CFM domain including said BRAS. 3. The control method suitable for working with the access network according to claim 1, wherein said Ethernet CFM frame is created by said BRAS, responsive to a port request message from an AAA server, operatively connected to said access network. 4. The control method suitable for working with the access network according to claim 1, wherein said proprietary protocol is configured to transmit operation, administration, and management (OAM) messages in an Ethernet in First Mile (EFM) network. 5. The control method suitable for working with the access network according to claim 1, wherein said proprietary protocol is configured to transmit operation, administration and management (OAM) messages in asynchronous transfer (ATM) mode. 6. The control method suitable for working with the access network according to claim 1, wherein said IWF associated with said access node comprises an end-of-service point (MEP) that is part of an Ethernet CFM domain defined on a virtual local area network (VLAN) ) 7. The control method suitable for working with the access network according to claim 6, wherein said VLAN can operate with a 1: 1 port addressing scheme. 8. The control method suitable for working with the access network according to claim 6, wherein said VLAN can operate with an N: 1 port addressing scheme. 9. An end-node control system using Ethernet connection error management (CFM) functionality associated with an access network, wherein said access network includes at least one access node connected to one or more end nodes and a broadband access server (BRAS ) connected by an authentication, authorization and accounting server (AAA) in a regional Ethernet network, containing:
means associated with said BRAS for creating an Ethernet connection error control (CFM) frame responsive to a port request message from an AAA server in a regional Ethernet network routed to an access node in which said Ethernet CFM frame includes a request message for a particular end a node serviced by said access node;
interworking function (IWF) means associated with said access node for interpreting said Ethernet CFM frame and embedding the corresponding request message in a proprietary protocol compatible with said specific end node; and means associated with said specific end node operating in response to said corresponding request message from said access node to generate a response message in said own protocol routed to said access node,
wherein said IWF means acts to interpret said response message in said native protocol and embeds an Ethernet CFM response frame including a response corresponding to said response message and said Ethernet CFM response frame for transmitting said BRAS; and
wherein BRAS creates a port request response to the AAA server responsive to the Ethernet CFM response frame. 10. The control system associated with the access network of claim 9, wherein said means of creating said Ethernet CFM frame is operative in response to a port request message from an AAA server operatively connected to said access network. 11. The control system associated with the access network of claim 9, wherein said proprietary protocol is suitable for transmitting operation, administration, and management (OAM) messages in an Ethernet in First Mile (EFM) network. 12. The control system associated with the access network of claim 9, wherein said proprietary protocol is suitable for transmitting operation, administration, and management (OAM) messages in asynchronous transfer (ATM) mode. 13. The control system associated with the access network of claim 9, wherein said IWF associated with said access node comprises an endpoint (MEP) that is part of an Ethernet CFM domain defined on a virtual local area network (VLAN). 14. The control system associated with the access network of claim 13, wherein said VLAN can operate with a 1: 1 port addressing scheme. 15. The control system associated with the access network of claim 13, wherein said VLAN can operate with an N: 1 port addressing scheme. 16. The monitoring system associated with the access network of claim 9, wherein said specific end node comprises a digital subscriber line (DSL) modem port. 17. The control system associated with the access network of claim 9, wherein said specific end node comprises a resident gateway (RG) port. 18. The monitoring system associated with the access network of claim 9, wherein said specific end node comprises a port of network terminal stations (NT). 19. A network element for monitoring end nodes using Ethernet connection error management (CFM) functionality, suitable for operation in an access network, comprising:
a logical structure configured to interpret a CFM frame received from a broadband access server (BRAS) located in said access network, said Ethernet CFM frame including a field that determines the type of request message and useful data that includes identification an end node served by said network element functioning as an access node;
a logical structure configured to embed the corresponding request message in a proprietary protocol compatible with said end node, said corresponding request message being based on said request message in said Ethernet CFM frame;
a logical structure configured to interpret the response message provided by said end node in said own protocol responsive to said corresponding request message; and
a logical structure configured to embed an Ethernet CFM response frame including a response corresponding to said response message received from said end node, said Ethernet CFM response message for transmission to said BRAS. 20. The network element according to claim 19, wherein said proprietary protocol is suitable for transmitting operation, administration, and management (OAM) messages in an Ethernet in First Mile (EFM) network. 21. The network element according to claim 19, wherein said native protocol is suitable for transmitting operation, administration, and management (OAM) messages in asynchronous transfer (ATM) mode.

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