Abstract:
A communications network, comprising a plurality of nodes supporting connection-oriented traffic and connectionless traffic, wherein management traffic between the nodes is propagated as connectionless traffic having a unique management traffic Virtual Local Area Network (VLAN) identifier (VID), and wherein at least one node is configured to perform a Link Layer Discovery Protocol (LLDP) exchange operation to enable detection of inconsistent provisioning of the Management VID in at least one node. Also disclosed is a communications network component, comprising logic that enables connection-oriented traffic and VLAN-based connectionless traffic, wherein the logic propagates management messages as VLAN-based connectionless traffic having a management VID, and wherein the logic enables detection of inconsistent management VIDs in a network.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority to U.S. Provisional Patent Application Ser. No. 60/914,432 filed Apr. 27, 2007 by Sultan et al. and entitled “System for Connectivity Fault Management in Networks Supporting Both Connectionless and Connection-Oriented Traffic.” The present application also claims priority to U.S. Provisional Patent Application Ser. No. 60/970,428 filed Sep. 6, 2007 by Sultan et al. and entitled “Data Communications Network for the Management of an Ethernet Transport Network.” The present application also claims priority to U.S. Provisional Patent Application Ser. No. 61/016,332 filed Dec. 21, 2007 by Sultan et al. and entitled “Method of Verifying DCN VID Provisioning Consistency.” These provisional applications are incorporated herein by reference as if reproduced in their entirety. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       REFERENCE TO A MICROFICHE APPENDIX 
       [0003]    Not applicable. 
       BACKGROUND 
       [0004]    Modern communication and data networks are comprised of nodes that transport data through the network. The nodes may include routers, switches, and/or bridges that transport the individual data frames and/or packets through the network. Some networks support both connectionless frame transfer (e.g., Provider Backbone Bridging (PBB)) and connection-oriented frame transfer (e.g., PBB Traffic Engineering (PBB-TE)). Providing management services (e.g., Data Communication Network services and/or connectivity fault management) in such networks is desirable. Further, ensuring that management services function properly in such networks is desirable. 
       SUMMARY 
       [0005]    In a first aspect, the disclosure includes a communications network, comprising a plurality of nodes supporting connection-oriented traffic and connectionless traffic, wherein management traffic between the nodes is propagated as connectionless traffic having a unique Management Virtual Local Area Network (VLAN) Identifier (VID), and wherein at least one node is configured to perform a Link Layer Discovery Protocol (LLDP) exchange operation to enable detection of inconsistent provisioning of the Management VID in at least one node. 
         [0006]    In a second aspect, the disclosure includes a communications network component, comprising logic that enables connection-oriented traffic and VLAN-based connectionless traffic, wherein the logic propagates management messages as VLAN-based connectionless traffic having a management VID and wherein the logic enables detection of inconsistent management VIDs in a network. 
         [0007]    In a third aspect, the disclosure includes a communications network component comprising at least one processor configured to implement a method comprising supporting connection-oriented traffic and VLAN-based connectionless traffic associated with a management VID, and transmitting a management VID type, length, value (TLV) data unit. 
         [0008]    These and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts. 
           [0010]      FIG. 1  is a block diagram of a system with a Data Communications Network (DCN). 
           [0011]      FIG. 2  is a block diagram of an embodiment of an Ethernet Transport Network (ETN) managed via an Ethernet DCN. 
           [0012]      FIG. 3A  shows an embodiment of a LLDP Data Unit (LLDPDU). 
           [0013]      FIG. 3B  shows an embodiment of management VID TLV extension for an LLDPDU. 
           [0014]      FIG. 3C  shows an embodiment of an LLDP agent. 
           [0015]      FIG. 3D  shows an embodiment of an LLDP method. 
           [0016]      FIG. 4  is a block diagram of an embodiment of a network component. 
           [0017]      FIG. 5  is a flowchart of an embodiment of a management method. 
           [0018]      FIG. 6  is a block diagram of an embodiment of a general-purpose network component. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    It should be understood at the outset that although an illustrative implementation of one or more embodiments are provided below, the disclosed systems and/or methods may be implemented using any number of techniques, whether currently known or in existence. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims along with their full scope of equivalents. 
         [0020]    At least some embodiments of the disclosure involve management traffic in a hybrid network environment that supports connection-oriented traffic and connectionless traffic (e.g., traffic based on VLANs). For example, connection-oriented frame transfers may be based on PBB-TE and connectionless frame transfers may be based on PBB. 
         [0021]    In accordance with some embodiments, management traffic is propagated as connectionless traffic associated with a Management VLAN, identified by a Management VID. In an Ethernet embodiment, the Management VID may be a VID that is temporarily provisioned or globally reserved for management traffic. The management traffic may correspond to Connectivity Fault Management (CFM) messages, Operation, Administration, Management, and Provisioning (OAM&amp;P) messages, configuration and backup files, billing data, software downloads, or other management traffic. To verify the Management VID is provisioned identically throughout the network, embodiments support exchanging Management VID information between adjacent nodes. For example, a node may exchange a LLDPDU with each neighboring node. In some embodiments, the LLDPDU is formatted according to the IEEE 802.1AB protocol (LLDP). By broadcasting Management VID information, discrepancies in Management VID provisioning and/or Management VID values can be detected and flagged. As desired, Management VID provisioning can be corrected and/or updated to support the propagation of management traffic in a network. 
         [0022]      FIG. 1  is a block diagram of an embodiment of a system  100  with a DCN  120 .  FIG. 1  is provided to better understand the use of the term DCN in the disclosure. In  FIG. 1 , a telecommunications service provider may deploy network elements  130  such as Synchronous Optical Network (SONET) or Synchronous Digital Hierarchy (SDH) components. The DCN  120  is deployed to support management connectivity between an Operations Support System (OSS)  110  and individual network elements  130 , which comprise a Transport Network. The DCN  120  (e.g., International Telecommunication Union Standardization Sector (ITU-T) G.7712/Y.1703) makes it unnecessary to provide direct connections between the OSS  110  and each individual network element  130  of the transport network. The DCN  120  requires the deployment of a routing protocol such as Open Systems Interconnect (OSI) routing or Internet Protocol (IP) routing in the network elements  130 . Information carried by the DCN  120  includes OAM&amp;P messages, configuration and backup files, billing data, and software downloads. 
         [0023]    In at least some embodiments, an instance of a bridged VLAN, known as a Management VLAN, supports connectivity between a Network Management System (NMS) and the bridging devices associated with an Ethernet Transport Network (Institute of Electrical and Electronic Engineers (IEEE) Draft Std. 802.1Qay). The role of the VLAN with respect to the Ethernet Transport network is similar to the role of the DCN (ITU-T G.7712/Y.1703)  120  in a traditional (e.g., SONET/SDH) telecommunications network. The VLAN used for this purpose may be called an Ethernet DCN. 
         [0024]    Embodiments provide an efficient method of interconnecting a NMS with Ethernet Transport Devices (802.1Qay compliant bridges) because it is unnecessary to provide a direct connection between the NMS and each individual Ethernet Transport Device. This is similar to the efficiency provided by a DCN in a SONET network. A particular advantage of using a VLAN for this purpose is that the 802.1 Qay bridge natively supports VLANs. This makes it unnecessary to introduce additional protocols to the 802.1 Qay bridge in order to support the DCN function. 
         [0025]      FIG. 2  is a block diagram of an embodiment of an ETN  150  managed using a reserved VLAN  190  that acts as an Ethernet DCN. In at least some embodiments, the ETN  150  follows the IEEE Draft Std. 802.1Qay protocol, which specifies the means by which 802.1Qay bridges  180  may be used to support traffic-engineered paths. A network deploying such paths can transport data in a manner similar to a SONET or SDH network. In  FIG. 2 , the ETN  150  is managed by a NMS  160  in a manner similar to the way in which a SONET-based transport network is managed by the OSS  110 . As in the case of the SONET-based transport network, it is useful to avoid the direct interconnection between the NMS  160  and each bridge  180  within the ETN  150 . It is observed that the 802.1 Qay-compliant bridges  180  can concurrently support instances of VLANs and instances of traffic-engineered paths  192 . In  FIG. 2 , DCN-type services in the ETN  150  are provided using the reserved VLAN  190 , which interconnects the NMS  160  with ETN devices  180 . In this manner, direct connection of the NMS  160  with each individual device  180  is unnecessary and an additional network technology need not be introduced to support the Ethernet DCN. This can be contrasted with the use of a traditional DCN  120  that requires the introduction of a layer three protocol, such as OSI routing or IP routing, in the network elements  130 . 
         [0026]    In general, the reserved VLAN  190  of the ETN  150  can be used to carry the same types of information as the traditional DCN, which includes OAM&amp;P (such as alarm, control, and test messages), configuration and backup files, billing data, and software download. In addition, the reserved VLAN  190  is useful in carrying CFM information related to traffic-engineered Ethernet paths. For additional information regarding CFM services in hybrid communication networks, reference is made to U.S. patent application Ser. No. 12/056,405 filed Mar. 27, 2008 by Sultan et al. and entitled “Fault Verification for an Unpaired Unidirectional Switched-Path” and to U.S. Provisional Patent Application Ser. No. 60/914,432 filed Apr. 27, 2007 by Sultan, et al. and entitled “System for Performing Connectivity Fault Management in Networks Supporting Both Connectionless and Connection-Oriented Traffic”, which are herein incorporated by reference as if reproduced in their entirety. 
         [0027]    The reserved or provisioned DCN VLAN  190  enables connectivity among all nodes/bridges in the entire ETN  150 . The PBB-TE protocol requires all network connectivity paths to be explicitly created (instead of spanning tree). For a network with only PBB-TE paths, intermediate nodes along each PBB-TE paths cannot reach each other. By creating an Ethernet DCN, all the nodes/bridges in the PBB-TE network are ensured to be reachable from any specific node. In such case, various management functions can be supported. For example, the Ethernet DCN can support remote access from any PBB-TE nodes to other PBB-TE nodes. In this manner, an operator at one location can remotely login to another node to perform OAM&amp;P functions. Additionally or alternatively, the reserved VLAN  190  supports segment connectivity testing or other diagnostic operations. As an example, any intermediate node can test its connectivity to other nodes along ESP paths. Using such connectivity testing faults can be isolated along any PBB-TE segment. 
         [0028]    In accordance with some embodiments, the reserved or provisioned DCN VLAN  190  is associated with a management VID. To ensure consistent provisioning of the management VID to the devices  180  of the ETN  150 , each device  180  is configured to exchange management VID information with neighboring devices. For example, an LLDPDU containing a Management VID TLV field specifying the locally provisioned management VID can be exchanged by each device  180  with its neighbor. In other words, each given device  180  may disclose to its neighbor devices whether a management VID has been provisioned to the given device and, if so, the value of the management VID. In this manner, any discrepancies in management VID provisioning can be detected and resolved. 
         [0029]    In at least some embodiments, network nodes maintain configuration information in the form of management information bases (MIBs) that are typically accessible via Simple Network Management Protocol (SNMP). By enabling devices in a network to become aware of the configuration information for other nodes, provisioning or misconfiguration problems can be detected and resolved. The exchange of configuration information between neighboring bridges of a network is defined by IEEE 802.1AB, the LLDP. This protocol is intended to detect inconsistencies in provisioning, but does not currently specify the exchange of management VID values. Thus, at least some embodiments involve extending IEEE 802.1AB to include a TLV format that supports advertising management VID values between nodes of a network. 
         [0030]      FIG. 3A  shows an embodiment of an LLDPDU  200 . The LLDPDU  200  comprises mandatory TLVs including a Chassis ID TLV  202 , a Port ID TLV  204 , a Time-To-Live (TTL) TLV  206 , and an LLDPDU End TLV  210 . The Chassis ID TLV  202  identifies the sender (e.g., the bridge MAC address of the sender). The Port ID TLV  204  identifies the port from which the LLDPDU  200  is transmitted. The TTL TLV  206  indicates how long (e.g., in seconds) the information in the LLDPDU  200  is to be treated as valid information. The LLDPDU End TLV  210  indicates the end of TLVs in the LLDPDU  200 . 
         [0031]    The LLDPDU  200  has an extensible format that supports optional TLV extensions  208 . In accordance with embodiments, such a TLV extension  208  corresponds to a management VID TLV.  FIG. 3B  shows an embodiment of a management VID TLV  208  for the LLDPDU format. As shown in  FIG. 3B , the management VID TLV  208  comprises a TLV header  220  and a TLV information string  230 . The TLV header  220  includes an extension type field  222  for identifying TLV extensions, which may be about seven bits in length. The TLV header  220  also includes a TLV information string length field  224  that indicates the length of the TLV information string  230 , and which may be about nine bits in length. For the management VID TLV embodiment shown in  FIG. 3B , the TLV information string has a length of about six octets. 
         [0032]    Octets  1 - 3  of the TLV information string  230  correspond to an Organizationally Unique Identifier (OUI) field  232  that identifies the OUI associated with each management VID TLV. Octet  4  of the TLV information string  230  corresponds to an 802.1 sub-type field  234  (e.g., subtype  6 ) associated with management VID TLVs. Finally, octets  5 - 6  of the TLV information string  230  correspond to a management VID field  236  that contains a management VID value. As an example, if a management VID has not been provisioned to a node, management VID TLVs transmitted from that node contain a zero value or null value in the management VID field  236 . If a management VID has been provisioned to a node, management VID TLVs transmitted from that node contain the value of the provisioned management VID in the management VID field  236 . By advertising the management VIDs between nodes of a network, inconsistencies in the provisioning of management VIDs can be detected. Such inconsistencies could result in the failure of management connectivity to nodes and resulting failure to control the nodes. 
         [0033]    For more information on extending IEEE 802.1AB to support new TLV extensions, reference is made to U.S. patent application Ser. No. 12/057,190 filed Mar. 27, 2008 by Sultan et al. and entitled “Method of Preventing Transport Leaks and VLAN Usage Conflicts in Hybrid Switching Networks by Extension of the Link Layer Discovery Protocol (LLDP).” This reference is incorporated herein by reference as if reproduced in its entirety. 
         [0034]    The IEEE 802.1AB Link Layer Discovery Protocol enables Ethernet devices to advertise information about themselves to neighboring network nodes as well as to store advertised information received from other neighboring network nodes.  FIG. 3C  shows an embodiment of an LLDP agent  240  that supports LLDP. As is understood in the relevant art, LLDP operates in a one-way direction. In other words, LLDPDUs are not exchanged as information requests by one device and responses sent by another device. Thus, a receiving device does not acknowledge LLDP information received from other devices. Rather, the receiving device stores and updates LLDP information, which is accessible to network administrators. 
         [0035]    In accordance with embodiments, various nodes of a network can implement at least one LLDP agent  240 . As shown, each LLDP agent  240  comprises an LLDP transmit module  250  and an LLDP receive module  260 . The LLDP transmit module  250  comprises an LLDP local system MIB  252  that stores the local system information (the local system refers to the node that implements the LLDP agent  240 ), which is to be transmitted by the LLDP agent  240 . The LLDP transmit module  250  also comprises an organizationally defined local device LLDP MIB extension  254  to support transmissions of organization specific information for the local node in the form of TLVs. 
         [0036]    Similarly, the LLDP receive module  260  comprises an LLDP remote system MIB  262  to maintain any remote system information received by the LLDP agent  240  from other nodes in a network. The LLDP receive module  260  also comprises an organizationally defined remote device LLDP MIB extension  264  to maintain organization specific information received from remote systems. In accordance with LLDP, the transmit (TX) and receive (RX) functions of the LLDP agent  240  can be controlled by state machines  242 . In at least some embodiments, the information stored in the LLDP transmit module  250  and the LLDP receive module  260  can be accessed and retrieved via the SNMP. 
         [0037]    To support transmission and reception of management VID information, the LLDP agent  240  can implement various features. For example, in some embodiments, LLDP agent  240  stores a table that controls the selection of LLPD management VID TLVs to be transmitted on individual ports. In addition, the LLDP agent  240  stores configuration information that specifies the set of ports on which a local system transmits management VIDs. The configuration information is restored from non-volatile storage upon re-initialization of a network&#39;s management system. Thus, each node that implements a LLDP agent  240  either comprises or has access to non-volatile memory from which such configuration information can be restored. In addition, the LLDP agent  240  stores a truth value that determines whether a management VID TLV transmission is allowed on a given node port (e.g., an LLDP transmission capable port). The truth value is restored from non-volatile storage upon re-initialization of a network&#39;s management system. Thus, each node that implements a LLDP agent  240  either comprises or has access to non-volatile memory from which such truth values can be restored. 
         [0038]    The LLDP agent  240  can be configured to operate in various modes. For example, in a transmit-only mode, the LLDP agent  240  can only transmit information regarding the capabilities and the current status of the local node. In other words, the LLDP transmit module  250  is active and the LLDP receive module  260  is inactive. In a receive-only mode, the LLDP agent  240  can only receive information about the capabilities and the current status of remote systems. In other words, the LLDP transmit module  250  is inactive and the LLDP receive module  260  is active. In a transmit/receive mode, the LLDP agent  240  can transmit the local system capabilities and status information as well as receive remote system&#39;s capabilities and status information. In other words, both the LLDP transmit module  250  and the LLDP receive module  260  are active. 
         [0039]    When active, the LLDP transmit module  250  transmits the local system&#39;s information at regular intervals using appropriate TLVs. When inactive, the LLDP transmit module  250  transmits LLDPDUs with a TTL TLV containing a zero value or null value in the information field. Upon receiving such an LLDPDU, remote systems can remove the information associated with the device that transmitted the LLDPDU from their MIBs  262 . 
         [0040]    When active, the LLDP receive module  260  receives information from remote systems and updates the remote system LLDP MIB  262 . When new information or updated information is received, the LLDP receive module  260  initiates a timer to track the “valid duration” indicated by the TTL TLV in each received LLDPDU. Once a timer expires, the information related to the timer is removed from the remote system LLDP MIB  262 . Alternatively, if the LLDP receive module  260  receives an LLDPDU with a TTL TLV containing a zero value or null value, the information related to the LLDPDU can be removed from the remote system LLDP MIB  262 . The protocol for storing and deleting information can be adjusted as desired in accordance with the amount of storage space provided for the MIBs  252  and  262 . 
         [0041]      FIG. 3D  shows an embodiment of an LLDP method  270 . As shown, the method  270  comprises advertising chassis/port IDs and system information via TLVs (block  272 ). In accordance with embodiments, management VID TLVs are advertised as part of the system information in block  272 . Received information is stored in local MIB databases accessible via SNMP (block  274 ). Finally, the network management system retrieves stored information from each device (block  276 ). By advertising, storing and accessing management VID information in the manner described for the method  270 , inconsistencies in the provisioning of management VIDs can be detected. 
         [0042]      FIG. 4  is a block diagram of an embodiment of a network component  300 . In  FIG. 4 , the network component  300  comprises logic  302  that supports various functions. The logic  302  may be representative of hardware, firmware, and/or software modules as understood by those of skill in the art. As shown, the logic  302  comprises a connection-oriented traffic module  304  that supports connection-oriented communications (represented by the solid arrows). The logic  302  also comprises a connectionless traffic module  306  that supports VLAN-based communications (represented by the dashed arrows). Finally, the logic  302  comprises a management traffic control module  308  that enables the network component  300  to generate and/or to handle management traffic associated with a particular VLAN. 
         [0043]    For example, in some embodiments, the management traffic control module  308  enables the network component  300  to generate a CFM message that is propagated as connectionless traffic. Additionally or alternatively, the management traffic control module  308  enables the network component  300  to generate OAM&amp;P messages, configuration and backup files, billing data, software downloads, or other management traffic as connectionless traffic. Additionally or alternatively, the management traffic control module  308  enables the network component  300  to respond to incoming management traffic. Regardless of the management traffic type and/or source, a management VID is associated with the management traffic. The management VID corresponds to the reserved or provisioned Management VLAN  250  and Ethernet DCN discussed previously with respect to  FIG. 2 . The management VID may be temporarily provisioned or globally reserved. 
         [0044]    The management traffic control module  308  also generates and/or handles management VID provisioning and management VID TLVs as described herein. In some embodiments, the management traffic control module  308  may generate management VID TLVs based on the TLV format and LLDP agent described previously in  FIGS. 3A-3D . For example, if a management VID has not been provisioned to the network component  300 , the management traffic control module  308  places a zero or null value in the management VID field of a management VID TLV. If a management VID has been provisioned to the network component  300 , the management traffic control module  308  places the value of the provisioned management VID in the management VID field of a management VID TLV. The management traffic control module  308  also may support various features such as the table, the configuration data, and the truth values described for  FIG. 3C . 
         [0045]      FIG. 5  is a flowchart of an embodiment of a management method  500 . As shown, the method  500  starts by sending a management VID TLV (block  502 ) to each active neighbor. The management VID TLV conveys information such as whether a management VID has been provisioned to the node broadcasting the TLV and, if so, the value of the management VID. At block  504 , inconsistent provisioning of management VID is detected based on broadcast management VID TLVs. Steps  502  and  504  can be performed by a single device or by multiple devices of a communications network. 
         [0046]    The components and methods described above may be implemented on any general-purpose network component, such as a computer, router, switch, or bridge, with sufficient processing power, memory resources, and network throughput capability to handle the necessary workload placed upon it.  FIG. 6  illustrates a typical, general-purpose network component suitable for implementing one or more embodiments of a node disclosed herein. The network component  600  includes a processor  602  (which may be referred to as a central processor unit or CPU) that is in communication with memory devices including secondary storage  604 , read only memory (ROM)  606 , random access memory (RAM)  608 , input/output (I/O) devices  610 , and network connectivity devices  612 . The processor may be implemented as one or more CPU chips. 
         [0047]    The secondary storage  604  is typically comprised of one or more disk drives or tape drives and is used for non-volatile storage of data and as an over-flow data storage device if RAM  608  is not large enough to hold all working data. Secondary storage  604  may be used to store programs that are loaded into RAM  608  when such programs are selected for execution. The ROM  606  is used to store instructions and perhaps data that are read during program execution. ROM  606  is a non-volatile memory device that typically has a small memory capacity relative to the larger memory capacity of secondary storage  604 . The RAM  608  is used to store volatile data and perhaps to store instructions. Access to both ROM  606  and RAM  608  is typically faster than to secondary storage  604 . 
         [0048]    While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented. 
         [0049]    In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled or directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.