DE102008055967A1 - End points i.e. maintenance entity points, addressing method for use in broadband access network, involves converting virtual network address into corresponding network address by transfer function to transmit message directed to end point - Google Patents

Abstract

The method involves forming a virtual network address (vMACa) from access nodes (AN) e.g. digital subscriber line multiplexer-demultiplexer, according to a given algorithm (vMAIg), and assigning end nodes (TEa-TEz) to network addresses (MACa-MACz). The virtual network address is formed from service nodes (SN) according to an algorithm (vMAIg') to transmit a message directed to an end point to the access nodes. The virtual network address is converted into the corresponding network address by a transfer function (IWF) to transmit the message directed to the end point.

Description

The The invention relates to a method for addressing at least one Endpoint in a network according to the preamble of the claim 1. Besides relates to the invention for a established network and an access node according to the generic term one of the independent claims. Especially The invention relates to an endpoint addressing in a network that having an access node and a service node connectable thereto, being over at least one interface of the access node of the network access for the at least one endpoint is established and the access node manages the network addresses of the connected endpoints.

The Invention should be especially for Applications in broadband access networks are suitable, the Internet access for Subscriber terminals via network elements, such as DSL modem, DSL access multiplexer and broadband IP access node set and performing of operation and maintenance tasks (Operation and Maintenance, short OAM) effectively.

Out The prior art is broadband based on Ethernet Access networks are known in which in the context of operating and maintenance tasks so-called Ethernet OAM messages between endpoints (Maintenance Entity Points) and defined intermediate points (Maintenance Intermediate Points) become.

The 1 schematically shows the structure of such a conventional network NW having an access node AN and a service node SN connectable thereto, wherein via at least one interface or port PRT of the access node AN the network access for the at least one endpoint, here for several endpoints (MEP: Maintenance Entity Point) MEPa to MEPz. These endpoints can be z. B. subscriber terminals TEa to TEz or access devices such. As DSL modems to be. The access node AN is usually a DSL multiplexer demultiplexer, which manages the network addresses MACa to MACz of the connected end points TEa to TEz. The network addresses are usually so-called MAC addresses (MAC: Media Access Control). Also, the access point AN itself as well as the service node SN each have their own network address, namely MAC # or MAC0.

Because without knowledge of the respective network addresses would be no connection and transmission of messages among the participating nodes possible. Between the access node AN and the service node SN even more nodes xN be interposed. Usually but is the respective source MAC address of the endpoints TEa to TEz not passed on to the other nodes, but their knowledge remains in the access node AN. The access node AN in turn orders the known real source MAC addresses MACa to MACz then known virtual source MAC addresses vMACa to vMACz and only this one to the other network elements on. If at least the virtual Addresses are known and a real existing endpoint address are assigned also from the network side, in particular from the service node SN, messages be directed to the individual end points TEa to TEz. Form and coding of such messages is in the standards of ITU-T (Y.1731) and IEEE (802.1ag, 802.1ah). However, they are concerned these standards only with the definition of PDU formats (PDU: Protocol Data Unit) and mechanisms. It is not specified there, in particular in an Ethernet network the address of the respective end point (so-called. OAM sink) could reach the service point or starting point (so-called OAM source). however can only by knowing the network address of an endpoint (MEP: Maintenance Entity Point) a corresponding message flow, so called OAM Flow. It should also be noted that the Network addresses of the endpoints often only a predetermined period of validity have, and thus it can happen that a message is sent to an endpoint is addressed, with an already expired address is provided.

Therefore It is an object of the invention, a method of the aforementioned Art as well as an afterwards working network and a corresponding one Access node to improve so that the above-mentioned disadvantages advantageously overcome become. In particular, a secure and always feasible messaging be possible in the context of operating and maintenance tasks.

Is solved the object by a method having the features of the claim 1 and through a network and an access node with the features the corresponding independent claim.

Therefore It is proposed that from the access node according to a predetermined algorithm virtual network addresses are formed, the the network addresses of the end nodes are assigned to that of the Service node according to the same Algorithm if needed at least one of the virtual network addresses is formed to a message directed to a desired endpoint first to send to the access node, which then by means of a conversion function the virtual network address is converted to the corresponding network address is used to send the message to the endpoint.

Consequently is used both at the access node and at the service node alike and in particular synchronously performed the formation of virtual addresses, wherein is ensured by using the same algorithm that the service node exclusively forms such virtual addresses, which are also known in the access node and at least the interface to the desired endpoint, in particular but the real endpoint address will be assigned to the desired endpoint so that the message can reach the endpoint. The invention also has the advantage that the access node is not alone virtual Generate addresses and then the service node, z. B. over a Control channel, must communicate. In the context of OAM functions (OAM: Operations and Maintenance) gives the advantage that the mandatory ones Endpoint addresses are not provided in an administrative manner Need to become, but by the method according to the invention equally determined or calculated at the participating nodes become. Learning the addresses is also not necessary resulting in disk space requirements, especially in the access node can be significantly reduced. The determination or calculation of the Endpoint address only occurs at the moment of using the OAM functionality the operator. A preliminary calculation, storage or configuration not necessary.

The In particular, the invention presents a solution which makes it possible to the endpoint address in a "carrier Class "Ethernet to determine without this over a particular mechanism or channel from the OAM sink, in particular the access node, the OAM source, in particular the service node or BRAS (Broadband Remote Access Server).

Especially advantageous embodiments of the invention will become apparent from the Dependent claims.

Preferably is determined by the algorithm for the interface formed a predetermined number of virtual network addresses becomes. This will be for every interface or every port a defined stock (pool) formed by virtual addresses, thus ensuring that the service node always forms valid virtual addresses.

From It is also an advantage if, by means of the algorithm, depending on of at least one property of the interface the virtual one Network addresses are formed. Such properties can z. B. the structure, in particular the structure or Hierachie of hardware and / or software units of the access node. In this Relation can preferably be the dependence for the formation of the virtual Network addresses in a network node connectable to the service node be deposited. The network node can be outside the reference circle of the network presented here and in particular a database included in the mapping between ports and virtual addresses is deposited.

at the method according to the invention Preferably, the conversion function is performed by each of the Service node is checked and addressed to one of the endpoints, whether for the respective endpoint the network address in the access node is known, and if this is not the case, the message by means of a Collective address over the interface is forwarded. Thus, an intelligent Function for implementing the addressing, namely the inventive interworking function, used, which for the Case that is not valid Address of each end node is known, a collective address (so-called broadcast address). In this case, the invention is also the knowledge basis, that also by means of such a general address the Message can be forwarded exactly to the endpoint, because yes the respective endpoint over its assigned interface (port) is connected. Therefore can despite the use of such a group or group address the Forwarding specifically to the desired Endpoint done.

at The method proposed here may be performed by the access node the network addresses of the connected endpoints are managed, by determining the network addresses of the connected endpoints and stored, in particular determined such network addresses and renewed continuously, the only a predeterminable period of validity exhibit. Also can from the access node and the service node, the virtual network addresses be formed to other nodes of the network not the network addresses the terminals, but to communicate only the virtual network addresses.

• – von dem Zugangsknoten werden mittels des Algorithmus die virtuelle Netzwerk-Adressen gebildet;
• – von dem Zugangsknoten werden die virtuellen Netzwerk-Adressen der mindestens einen Schnittstelle und/oder den Netzwerk-Adressen der angeschlossenen Endpunkten zugeordnet;
• – von dem Diensteknoten wird mittels desselben Algorithmus zumindest eine der virtuelle Netzwerk-Adressen gebildet;
• – von einer mit dem Netzwerk verbindbaren Instanz wird der Dienstknoten angestoßen, um die an den jeweiligen Endpunkt gerichtete Nachricht an den Zugangsknoten zu senden;
• – von dem Dienstknoten wird eine der virtuellen Netzwerk-Adressen verwendet, um die an den jeweiligen Endpunkt gerichtete Nachricht (OAM-MSG; LBM; LTM) an den Zugangsknoten zu senden;
• – in dem Zugangsknoten wird die Umsetzungs-Funktion durchführt, indem geprüft wird, ob für diesen Endpunkt die Netzwerk-Adresse in dem Zugangsknoten bekannt ist, wobei:
• – die Nachricht mittels der Netzwerk-Adresse des Endknotens über die Schnittstelle weitergeleitet wird, falls diese Netzwerk-Adresse bekannt ist; oder
• – die eingehende Nachricht mittels der Sammeladresse über die Schnittstelle weitergeleitet wird, falls die Netzwerk-Adresse des Endknotens nicht bekannt ist, oder die Gültigkeitsdauer der Netzwerk-Adresse abgelaufen ist;
• – von dem Endknoten, an den die Nachricht gerichtet ist, wird eine Antwort-Nachricht für den Diensteknoten zunächst an den Zugangsknoten gesendet;
• – in dem Zugangsknoten wird die Umsetzungs-Funktion durchführt, um die Antwort-Nachricht mittels einer dem Dienstknoten zugeordneten Netzwerk-Adresse an den Diensteknoten weiterzuleiten.

In the method according to the invention, at least one of the following steps is preferably carried out:

• The virtual network addresses are formed by the access node by means of the algorithm;
• The virtual network addresses of the at least one interface and / or the network addresses of the connected end points are assigned by the access node;
• At least one of the virtual network addresses is formed by the service node by means of the same algorithm;
• From an entity connectable to the network, the service node is triggered to perform the send a message addressed to the respective endpoint to the access node;
• One of the virtual network addresses is used by the service node to send the message (OAM MSG, LBM, LTM) addressed to the respective end point to the access node;
• In the access node, the translation function is performed by checking whether the network address in the access node is known for this endpoint, wherein:
• - the message is forwarded via the interface using the network address of the end node, if that network address is known; or
• - the incoming message is forwarded via the interface via the interface, if the network address of the end node is not known, or the validity period of the network address has expired;
• From the end node to which the message is addressed, a response message for the service node is first sent to the access node;
• - In the access node, the conversion function is performed to forward the response message by means of a network node associated with the service node to the service node.

following the invention will be described in detail by means of exemplary embodiments, With reference to the accompanying figures, the following represent:

1 shows a conventional network structure;

2 shows a structure according to the invention in which virtual addresses are generated both in the access node and in the service node;

3 illustrates the transmission of messages, in particular messages for OAM functions directed from the service node to certain terminals;

4 shows in more detail the functional structure of an interworking function implemented in the access node; and

5 shows the schematic sequence of a method according to the invention.

The 1 shows a schematic representation of the structure of the above-mentioned network NW, which provides a broadband Internet access for multiple endpoints TEa to TEz. For this purpose, the network elements that are essentially involved and their functions have already been described in the introduction. A resulting problem is that network addresses for the end nodes TEa to TEz often have only a very short validity period. This may mean that, in particular, the service node SN can no longer send messages to the connected end points or terminals.

In 2 is in comparison to the basic structure 1 in accordance with the invention, both the access node AN and the service node Sn form the same algorithm vMAlg or vMAlg 'as a copy thereof for forming virtual addresses vMACa to vMACz according to the invention. Thus, the service node SN, which is here a broadband access server (so-called GRAS: Broadband Remote Access Server), is itself able to generate valid virtual addresses vMACa, vMACb, etc., which the access node AN or the Implementing function IMF implemented therein knows. Thus, the service node SN can, if necessary, address the messages OAM-MSG, which are required in particular for operation and maintenance, which are directed to the end nodes TEa to TEz at least as far as the access node AN, which then converts the addressing to real addresses MACa, MACb and so on to forward the messages to the desired device.

When An example is the situation when initiating an OAM function by the operator of an Ethernet based access network considered. Here is a valid one Endpoint address required. This would have to be conventional administrative be provisioned or provisioned. For the sake of clarity of Addresses of endpoint addresses as well as for security reasons virtual addresses (eg vMACa) are used, which are in the direction Network instead of real addresses (MACa). Uses according to the invention one the use of the virtual addresses in the access node AN and the knowledge that there the virtual addresses after a vorgebaren or fixed algorithm vMAlg be formed, now, too in the service node SN alike with vMAlg 'the virtual To form addresses, yes for the OAM function finally in the implementation IMF to the desired Endpoint address leads. For the calculation It is irrelevant to the endpoint address whether the customer terminal (eg. TEa) is currently active and DSL range is set up with it or not.

A conversion function IWF in the access node AN receives the OAM message to the desired endpoint address. From this address, the addressed DSL port PRT of the access node AN can be uniquely determined. The IWF replaces the original endpoint address with group address and forwards the OAM message to the DSL port PRT and thus to all there connected terminals TEa to TEz. Thus, the customer-end devices for the OAM functionality are reachable and addressable without the need for provisioning or learning the endpoint addresses beforehand. Furthermore, the entire transmission path of the OAM message is "in-band", ie the transmission runs over exactly the same paths or channels as the customer data also. This is especially helpful for a statement of the correct configuration at the aggregation level.

It is thus a special feature of the invention that the respective endpoint address of the customer terminal, which is absolutely necessary for the use of Ethernet OAM functions from the service node SN or BRAS, is not administrative (eg via a management system). must be provided, but is learned by the mechanisms described here from the network itself. As the 2 In detail, the access node AN has an interworking function IWF for this, which enables the exchange of the messages OAM-MSG between the service node SN and the respective end point TEa.

In addition, also on the 3 and 4 Referenced to the inventive method 100 to describe here in more detail:
The initial situation is the recognition that in the broadband access node AN each DSL port PRT certain MAC addresses are stored, here z. MACa to MACz. The corresponding virtual addresses, vMACa to vMACz, are formed by means of an algorithm which follows a fixed formation rule that is unique to the reference domain. A single DSL port PRT can be assigned multiple vMAC addresses.

To Synchronization of the DSL lines learns the access node AN the endpoint addresses the customer devices TEa to TEz or the connection between node AN and respective Terminal. At this time, the AN also assigns a virtual endpoint address, such as B. vMACa. The node AN now knows both real and virtual address of the customer's terminal, so TEa. Since the allocation algorithm in node AN is a fixed one Pool of vMAC addresses per DSL port PRT, the associated Although the vMAC address is changing, it comes from but always from the same pool that is assigned to the port PRT. Consequently, the node SN or BRAS can use the same algorithm at any time a valid vMAC address form or calculate to any DSL port of an AN node. It does not matter if this address vMAC is currently a real one Address MAC is assigned or not. The vMAC address is for this particular DSL port valid.

Performing Ethernet OAM loopback and OAM linktrace checks requires knowledge of the endpoint addresses at the opposite MEP (Maintenance Entity Point) endpoint. Knowledge of these MAC addresses can currently only be communicated to the MEP via configuration with conventional technologies. However, in order to be able to use this function in a mass-market-capable broadband telecommunications network, an automatic determination of these MAC addresses on the MEP is necessary. This solves the present invention by a method for determining or calculating this virtual endpoint address and by a special conversion function (OAM-IWF) on the AN as a link (see also 3 .). In this case, the calculation of a virtual endpoint address of a DSL port (vMAC) for the addressing of an OAM message takes place on the node BRAS according to exactly the same algorithm vMAlg 'as the algorithm vMAlg in the access node AN, which forms and assigns the vMAC there.

A OAM message becomes the access node through the calculated endpoint address AT. definitely reach. The contractor knows the state of the addressed DSL ports and can answer the incoming OAM message even then if the addressed DSL haven is not active, because z. B. the customer his terminals has shut off. However, if the DSL port is active, it takes a special one Conversion function on the AN (OAM interworking function, OAM-IWF) this OAM message. Because by addressing the virtual MAC address in the ON, the MEP3 in the terminal can not yet be reached. For this purpose, a special implementation function IMF is proposed, because such a feature in conventional solutions not available stands.

Like the 4 As a working principle, the IWF function consists of two virtual MEPs (MEP 'and MEP'') and replaces the endpoint address of the OAM message, which is still the calculated endpoint address, with a group address, which is one of all active terminals on the DSL port is detected and answered.

• • Nutzen des AN-Algorithmus zur Zuordnung der vMAC, um die Endpunktadresse auf dem AN im SN berechnen zu können.
• • Umsetung der Eth LBM bzw. LTM in einer OAM-IWF zum MEP3
• • Umsetzung der Eth LBR bzw. LTR in einer OAM-IWF zum MEP1

With reference to the in 5 the process sequence shown, the features and functional sequence are as follows:

• • Using the AN algorithm to map the vMAC to calculate the endpoint address on the AN in the SN.
• • Implementation of the Eth LBM or LTM in an OAM IMF to the MEP3
• • Implementation of the Eth LBR or LTR in an OAM IMF to the MEP1

In a first step 110 the access node AN learns the current network addresses of the connected terminals. The process of learning the respective endpoint address is triggered by the customer or user himself by connecting his terminal to the network NW or the access node AN. It is not triggered by the network operator by configuration o. Ä.

It is therefore an automatic process that allows, the endpoint addresses in a carrier class Ethernet network to learn and use Ethernet OAM functions.

In the broadband access node AN, each DSL port MAC addresses are stored. These MAC addresses are formed according to a defined rule, which are unique to the reference domain. Each DSL port can have n vMAC addresses (eg 1 ≤ n ≤ 64). However, this depends on the number of terminals TE to be connected. The number of addresses can be determined by configuration. To create the virtual addresses vMAC, a defined algorithm vMAlg is used (see also 2 ). Also, the service node SN forms vMAlg virtual addresses according to the same algorithm.

To Synchronization of the DSL lines learns the broadband access node TO the endpoint addresses of the client devices of the connection between Access node AN and the respective customer terminal, z. B. TEa. Thus knows the Access node AN the respective real endpoint address, so z. B. the MACa, as well as the associated virtual endpoint address vMACa of the customer terminal TEa.

The step taken at the beginning 110 is initiated by the customer by turning on or activating his terminal. This activation results in the establishment of the DSL link to the access node AN.

However, by addressing the virtual network addresses vMACa to vMACz in the access node AN, the end point in the respective terminal can not be reached. In order to reach the end point in the terminal, in step 130 the implementation function or interworking function IWF according to the invention is performed.

This function IWF checks in step 131 whether a real address is known for the endpoint, e.g. As the MACa, and arranges them in one step 132 the respective address known to the service node SN, here z. For example, the virtual vMACa. If no real address is known, or if a known address has already expired, the interworking function IWF assigns a collective MAC * address to the known address vMACa, thereby ensuring that the message, e.g. B. LBM, arrives safely at the desired endpoint TE.

One Another advantage of this method is the automatic integration possibly existing virtualization of endpoint addresses (eg. VMAC). Network operators are for the sake of clarity of Endpoint addresses as well as a function out of safety considerations in the AN, which is the "real" endpoint address of the customer terminal (eg MAC address) in the ON by virtual endpoint addresses in direction Network replaced. In a manual administration, this implementation would have taken into account become. The method described here takes account of this Circumstance automatically by the contractor. There are no further interventions required.

In summary, the invention is a method that allows for synchronous automatic endpoint address detection for Ethernet OAM without transmitting the endpoint addresses. As a reference circuit of the invention, for example, applies a broadband access network, as in 1 is shown. Usually, in such a broadband, preferably Ethernet-based, access network, the Ethernet OAM messages are sent between endpoints MEP and defined intermediate points MIP. The form and coding of these messages is in the standards such. B. according to ITU-T and IEEE defined. These known standards are concerned with the definition of formats and mechanisms. However, it does not specify how the addresses of the end points (OAM sink) reach the OAM source points in a network. However, only by knowing the endpoint address can an OAM flow be established.

At this juncture, the invention described proposes a mechanism that allows the endpoint address to be determined in a Carrier Class Ethernet, without the need for a specific mechanism from the OAM sink, such as the access node AN, to the OAM source how the service node SN or BRAS would have to be transmitted. A particular advantage of the invention is that the endpoint addresses, which are absolutely necessary for the Ethernet OAM functions, do not have to be provided administratively in any way, but can be determined or calculated by the mechanisms described here. Learning the addresses is also not required, which significantly reduces the memory requirements in the AN. The determination or calculation of the endpoint address takes place only when the operator is using the OAM functionality. A preliminary calculation, storage or configuration is not required sary.

It is known that when an OAM function is initiated by the operator of an Ethernet based access network, an endpoint address (MAC address) is required. The endpoint address (of the client terminal) would have to be administratively provisioned or provisioned. However, for reasons of uniqueness of endpoint addresses and for security reasons, network operators will use a function in the AN that replaces the "true" endpoint addresses of the customer end devices (eg MAC addresses) in the AN with virtual endpoint addresses (vMAC) towards the network, such as this 2 illustrated.

According to the invention now the use of this vMAC in the access node AN and the fact used, whose formation takes place according to a defined algorithm, in the service node SN or BRAS (OAM source) for the OAM function calculate the required endpoint address. For the calculation of the endpoint address It is irrelevant whether the customer terminal is currently active and the DSL Track is constructed or not.

Preferably takes a special conversion function IWF (OAM interworking function) in the access node TO the OAM message to this particular endpoint address. From the endpoint address can uniquely the addressed DSL port PRT of the access node AN. The implementation function IMF replaces the original endpoint address through a group address and sends the OAM message further to the DSL port and thus to all terminals connected there. With this method will be the customer end devices for the OAM functionality reachable and addressable, without any provisioning or learning of the endpoint addresses should have taken place. Farther is the entire transmission path of OAM message "inband", so runs therefore over exactly the same ways as the customer data too, which is specific to a statement the correct configuration at the aggregation level is helpful.

The functional sequence is as follows:
In the broadband access node AN each DSL port MAC addresses are stored. These MAC addresses are formed according to a defined rule, which are unique to the reference domain. A single DSL port can be assigned multiple vMAC addresses.

To Synchronization of the DSL lines learns the broadband access node TO the endpoint addresses of the customer devices of the connection between AN and customer terminal. At this time, the AN also assigns a virtual Endpoint address vMAC. The access node AN now knows both real as well as the virtual endpoint address of the customer's terminal. There the algorithm vMAlg the assignment in the access node AN a fixed Pool of vMAC addresses per DSL port If the assigned virtual address vMAC can change, it comes from but always from the pool that was assigned to this DSL port. Consequently For example, the service node SN or BRAS can use this algorithm vMAlg 'at any time calculate a valid vMAC to any DSL ports of an AN. It does not matter if this particular vMAC is currently assigned a "real" endpoint address is or not. The vMAC is for valid for this particular DSL port.

To perform Ethernet OAM loopback and link trace tests, it is essential to know the endpoint addresses on the opposite MEP in order for the feature to start. The knowledge of these MAC addresses can currently only be communicated to the MEP via configuration. However, in order to be able to use this function in a mass-market-capable broadband telecommunications network, an automatic determination of these MAC addresses on the MEP is necessary. The present invention also applies here and describes a method for determining or calculating this virtual endpoint address as well as a special conversion function (OAM-IWF) on the access node AN as a link (see 3 ).

highlight is the calculation of a virtual endpoint address vMAC of a DSL port for the Addressing an OAM message on the service node SN or BRAS according to exactly the same algorithm vMAlg 'as the algorithm vMAlg in the access node AN that forms and maps the virtual addresses vMAC.

An OAM message will reach the access node AN by the calculated endpoint address in any case. The access node AN knows the state of the addressed DSL ports and can answer the incoming OAM message itself, if the addressed DSL port is not active, ie if z. B. the customer has switched off his terminals. However, if the DSL port is active, the special conversion function IWF on the access node AN receives this OAM message. Because only by addressing the virtual address in the access node AN, the MEP3 can not be reached in the terminal yet. However, the conversion function IWF can do this and preferably consists of two virtual MEPs (MEP 'and MEP'') and replaces the endpoint address of the OAM message, which is still the calculated endpoint address, with a group address, which of all active terminals on the DSL port is detected and answered. A non-answering due Inactive terminal is signaled to the SN by the ON either by time out or by an error message to be defined.

LIST OF REFERENCE NUMBERS

• TEi

  Endpoint (s) or subscriber terminal (s), executed as MEP (Maintenance Entity) regarding OAM function

  AT

  Access node (Access Node) as an intermediate point or MIP (Maintenance Intermediate Point) regarding. OAM function

  SN

  Service node (Service Node) as BRAS Broadband Access Node or Server (Broadband Remote Access Server

  NET

  Network, if necessary, with further network nodes

  MACi

  real network address (s) (Media Access Control)

  vMACi

  virtual network addresses

  IMF

  Conversion function or interworking function

  vMAlg

  virtual MAC algorithm (BRAS)

  vMAlg '

  virtual MAC algorithm (AT)

  OAM MSG

  Message (OAM: Operation and maintenance)

  LBM, LBR

  News regarding OAM functions (loop back message or loop back report message)

Claims (15)

Procedure ( 100 ) for addressing end points (TEa,... TEz) in a network (NW) having an access node (AN) and a service node (SN) connectable thereto, wherein the access node (AN) has at least one interface (PRT) Network access for the endpoints (TEa, ... TEz) is established and the access node (AN) manages the network addresses (MACa, ... MACx, MACy, MACz) of the connected endpoints (TEa, ... TEz), thereby characterized in that the access node (AN) according to a predetermined algorithm (vMAlg) virtual network addresses (vMACa, ... vMACz) are formed, the network addresses (MACa, ... vMACz) of the end nodes (TEa, ... TEz) such that at least one of the virtual network addresses (vMACa) is formed by the service node (SN) according to the same algorithm (vMAlg ') to a message (OAM-MSG; LBM) directed to an end point (TEa) to send the access node (AN), wherein by means of a conversion function (IMF) the virtual Network address (vMACa) is converted into the corresponding network address (MACa) to the message (OAM-MSG; LBM) to the end point (TEa). Procedure ( 100 ) according to claim 1, characterized in that by means of the algorithm for the interface (PRT) a predeterminable number of virtual network addresses (vMACa, ... vMACz) is formed. Procedure ( 100 ) according to claim 1 or 2, characterized in that by means of the algorithm in dependence on at least one property of the access node (AN), in particular its logical structure, the virtual network addresses (vMACa, ... vMACz) are formed. Procedure ( 100 ) according to claim 3, characterized in that the logical structure of the access node (AN) corresponds to a hierarchical structure of hardware and or software units, in particular with respect to an addressing. Procedure ( 100 ) according to any one of the preceding claims, characterized in that by triggering the service node (SN), if necessary, a message (OAM-MSG; LBM; LTM) directed to an end point (TEa) is transmitted. Procedure ( 100 ) according to any one of the preceding claims, characterized in that the conversion function (IWF) is performed in particular in the access node (AN) by checking (OAM) each message coming from the service node (SN) and directed to one of the endpoints (TEa) -MSG; LBM) is checked ( 151 ), whether the network address (MACa) in the access node (AN) is known for the respective end point (TEa), and if this is not the case, the message (LBM) via a common address (MAC *) via the interface ( PRT) is forwarded ( 153 ). Procedure ( 100 ) according to one of the preceding claims, characterized in that the network addresses (MACa, ... MACx, MACy, MACz) of the connected end points (TEa, ... TEz) are managed by the access node (AN) by the network Addresses (MACa, ... MACx, MACy, MACz) of the connected endpoints (TEa, ... TEz) are determined and stored ( 110 ), in particular those network addresses are determined and renewed continuously, which have only a predeterminable period of validity. Procedure ( 100 ) according to one of the preceding claims, characterized in that at least one of the following steps is carried out: - Step 110 from the access node (AN) the virtual network addresses (vMACa, ... vMACx, vMACy, vMACz) are formed by means of the algorithm (vMAlg); - Step 120 : from the access node (AN) the virtual network addresses (vMACa, ... vMACx, vMACy, vMACz) of the at least one interface (PRT) and / or the network addresses (MACa, ... MACx, MACy, MACz) of the connected endpoints (TEa,. .. TEz) assigned; - Step 130 : from the service node (SN) at least one of the virtual network addresses (vMACa) is formed by means of the same algorithm (vMAlg); - Step 130 a network-connectable entity triggers the service node (SN) to send the message (OAM-MSG; LBM; LTM) directed to the respective endpoint (TEA) to the access node (AN); - Step 140 the service node (SN) uses one (vMACa) of the virtual network addresses to send the message (OAM-MSG, LBM, LTM) to the access node (AN) to the respective endpoint (TEa); - Step 150 in the access node (AN), the conversion function (IWF) is performed by checking whether the network address (MACa) in the access node (AN) is known for this end point (TEa), wherein: - step 151 the message (LBM; LTM) is forwarded via the network address (MACa) of the end node (TEa) via the interface (PRT) if that network address (MACa) is known; or - step 152 the incoming message (LBM; LTM) is forwarded by means of the aggregate address (MAC *) via the interface (PRT) if the network address of the end node (TEa) is not known or the validity period of the network address has expired; - Step 160 from the end node (TEa) to which the message (LBM; LTM) is directed, a response message (LBR; LTR) for the service node (SN) is first sent to the access node (AN); - Step 170 in the access node (AN), the conversion function (IWF) is performed in order to forward the response message (LBR; LTR) to the service node (SN) by means of a network address (MAC0) assigned to the service node (SN). Network (NW) with an access node (AN) and with a service node (SN) connectable thereto, the access node (AN) at least one interface (PRT) for connecting at least one Endpoint (TEa ... TEz) and the network addresses (MACa, ... MACx, MACy, MACz) of the connected end point (TEa ... TEz) managed, characterized that the access node (AN) according to one predefinable algorithm (vMAlg) virtual network addresses (vMACa, ... vMACz) and the network addresses (MACa, ... vMACz) of the Assigns end nodes (TEa, ... TEz), that the service node (SN) according to the same Algorithm (vMAlg) at least one of the virtual network addresses (vMACa) to one aimed at one of the endpoints (TEa) Message (OAM-MSG; LBM; LTM) to the access node (AN), in which the access node (SN) by means of a conversion function (IMF) the virtual network address (vMACa) in the appropriate network address (MACa) translates to the message (OAM-MSG, LBM, LTM) to the endpoint (TEa). Network (NW) according to claim 9, characterized that the connected endpoints have several subscriber terminals (TEa, ... TEz) and / or connection devices, especially DSL modems, which are accessible via the access node (AN) with the service node (SN) messages, in particular messages for operating and maintenance (OAM-MSG). Network (NW) according to claim 9 or 10, characterized the access node (AN) is a multiplexer-demultiplexer, in particular a DSL Mux Demux, is. Network (NW) according to one of claims 9 to 11, characterized in that the service node (SN) comprises a broadband network access node, in particular a broadband access server (BRAS), is. Network (NW) according to one of claims 9 to 12, characterized in that the network at least for the operational and maintenance purposes is constructed as Ethernet. Access node (AN) for a network (NW) containing the Access node (AN) and a service node (SN) that can be connected to it wherein the access node (AN) has at least one interface (PRT) for connecting at least one end point (TEa ... TEz) and the network addresses (MACa, ... MACx, MACy, MACz) of the connected Managed endpoint (TEa ... TEz), characterized, that the access node (AN) according to a predefinable algorithm (vMAlg) virtual network addresses (vMACa, ... vMACz) and the network addresses (MACa, ... vMACz) of the End node (TEa, ... TEz) assigns that the service node (SN) according to the same Algorithm (vMAlg) at least one of the virtual network addresses (vMACa) to one aimed at one of the endpoints (TEa) Message (OAM-MSG; LBM) to the access node (AN), in which the access node (SN) by means of a conversion function (IMF) the virtual network address (vMACa) in the appropriate network address (MACa) translates to the message (OAM-MSG; LBM) to the endpoint (TEa). Access node (AN) according to claim 14, since characterized in that the conversion function (IWF) is integrated in the access node (AN).