Abstract:
A communications system for remotely managing equipment includes a first remote device and a second remote device having the same network address. A communications network includes a first link connecting the first remote device to a management station and a second, disparate link connecting the second remote device to the management station. The management station is operable to individually access the first remote device via the first link and to individually access the second remote device via the second link.

Description:
RELATED APPLICATIONS 
     This application is related to copending U.S. patent application Ser. No. 09/129,199, entitled “METHOD AND SYSTEM FOR AUTOMATIC LINE PROTECTION SWITCHING OF EMBEDDED CHANNELS,” filed Aug. 4, 1998 and U.S. patent application Ser. No. 09/129,201, entitled “SYSTEM AND METHOD FOR EMULATING A DISTRIBUTED NETWORK,” filed Aug. 4, 1998. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     This invention relates generally to communications systems, and more particularly to a method and system for remote management of equipment having duplicate network addresses. 
     BACKGROUND OF THE INVENTION 
     With the move toward decentralized processing, users have interconnected workstations, computers and other types of local equipment through local area networks (LANs). More recently, as users move toward global communications that allow equipment to appear as if it were attached to the local area network, local area networks have been interconnected through wide area networks (WANs). 
     Due to the success of the Internet, the Internet Protocol (IP) has become the primary networking protocol. To make routing efficient, the Internet Protocol uses addresses that include a network portion and a host portion. Internet Protocol addresses are assigned to the interconnection of a host to a physical network. 
     Independent assignment by each user of Internet Protocol addresses to its own equipment has lead to duplication of Internet Protocol addresses between users. As a result, while a user may access its equipment over an intranet or other closed network using an independently assigned Internet Protocol address, the user cannot rely on that Internet Protocol address to access the equipment over the Internet or other open network. For this reason, a service provider cannot provide remote services for globally distributed equipment belonging to various users. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a remote management method and system are provided that substantially eliminate or reduce disadvantages or problems associated with previously developed systems and methods. In particular, the present invention provides a remote management system and method that individually accesses equipment having duplicate network addresses. 
     In accordance with one embodiment of the present invention, a communications system for remotely managing equipment includes a first remote device and a second remote device having the same network address. A communications network includes a first link connecting the first remote device to a management station and a second, disparate link connecting the second remote device to the management station. The management station is operable to individually access the first remote device via the first link and to individually access the second remote device via the second link. 
     More specifically, in accordance with a particular embodiment of the present invention, the network address is an Internet Protocol (IP) address. The communications network is a frame relay network, and the first and second links are each an embedded channel, such as a private virtual channel (PVC) of a network trunk. 
     Technical advantages of the present invention include providing a remote management system for equipment having duplicate network addresses. In particular, remote devices are separately linked through an open network to a management station. This is accomplished by linking each remote device to a separate input of a switch. The management station is operable to access the remote devices based on addresses associated with the switch inputs. In this way, service providers may remotely access and service equipment over an open network without the cost of maintaining the network addresses as unique. 
     Other technical advantages of the present invention will be readily apparent to one skilled in the art from the following figures, descriptions, and claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein like reference numerals represent like parts, in which: 
     FIG. 1 is a schematic block diagram illustrating a communications system for remote management of customer premise equipment in accordance with one embodiment of the present invention; 
     FIG. 2 is a schematic block diagram illustrating primary and secondary embedded channels for the management network of FIG. 1; and 
     FIG. 3 is a flow diagram illustrating a method of automatic line protection switching between the primary and secondary embedded channels of the management network of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 illustrates a communications system  10  for remote management of customer equipment in accordance with one embodiment of the present invention. The communications system  10  includes a plurality of customer sites  12 A,  12 B and  12 C connected through a communications network to a management site  16 . The customer site  14  may be globally distributed and thus remote from each other and the management site  16 . 
     Referring to FIG. 1, each of customer site  12  includes an item of customer premise equipment (CPE)  20 , a local area network (LAN)  22 , and a local network equipment  24 . The customer premise equipment  20  may be a telephony switch, other telephony equipment, or other type of equipment that is remotely distributed and operated. 
     The customer premise equipment  20  includes a network interface system (NIS)  30 , a command and control (C&amp;C) system  32 , and a performance (Perf.) system  34 . The network interface system  30  connects the customer premise equipment  20  to the communications network  14 . For the embodiment of FIG. 1 in which the communications network is a frame relay network, the network interface system is a frame relay with router (FRAD). The frame relay with router encapsulates and decapsulates messages and data transmitted and received over the communications network  14 . 
     The command and control system  32  includes software that manages the operation of the customer premise equipment  20  and the local network equipment  24  through the customer premise equipment  20 . The command and control system  32  includes a network address  36  with which the command and control system  32  can be accessed. In one embodiment, the network address  36  is an Internet Protocol (IP) address. The Internet Protocol address is a 32-bit address that includes a network portion and a host portion for efficient routing. 
     The performance system  34  includes software and memory for monitoring, recording, and storing performance data for the customer premise equipment  20  and the local network equipment  24  through the customer premise equipment  20 . The performance system  34  includes a network address  38  with which the performance system  34  can be accessed. In one embodiment, the network address  38  is an Internet Protocol address. 
     Because the Internet Protocol addresses of the command and control systems  32  and the performance systems  34  are independently assigned by each customer, the Internet Protocol addresses may be duplicated between the customer premise equipment  20 . For example, the command and control system  32  of customer A&#39;s premise equipment  20  may have the same Internet Protocol address as the command and control system  32  for customer B&#39;s premise equipment  20 . Similarly, the performance system  34  for customer C&#39;s premise equipment  20  may have that same Internet Protocol address. As described in more detail below, the present invention allows such systems and equipment having duplicate Internet Protocol addresses to be individually accessed and remotely managed over an open network. An open network is a public network or other network in which network addresses may be duplicated. 
     The local area network  22  of each customer site  12  is connected to a network port of the customer premise equipment  20  of that site. The local area network  22  may be an Ethernet or other suitable type of local network. The local equipment  24  connected to the local area network  22  may be servers, databases, or other suitable devices accessed by the customer premise equipment  20 . 
     The communications network  14  is a wide area network (WAN) that connects the customer sites  12  to the management site  16 . For the embodiment of FIG. 1, the communications network  14  is a frame relay network. The frame relay network uses a packet-switching protocol for connections between remote locations. The packets are in the form of frames which are variable in length. An advantage to the frame relay network is that data packets of various sizes associated with virtually any native data protocol can be accommodated. As a result, the frame relay network is protocol independent because it does not undertake a lengthy protocol conversion process and offers fast and less expensive switching and/or routing. The frame relay network may include the series of hubs, switches, bridges, and routers for transmitting traffic between the customer sites  12  and the management site  16 . 
     The frame relay network includes operational links  40  and management links  42  for the customer premise equipment  20  of each client site  12 . The operational link  40  connects the customer premise equipment  20  to a remote host  44  which provides database and other operating information for the customer premise equipment  20 . The remote host  44  may be a server or other suitable device. 
     The management links  42  form a robust management network  46  within the communications network  14 . In one embodiment, as described in more detail below, each management link  42  includes an embedded channel defined in a network trunk. The network trunk may be a T 1  and the embedded channel may be a private virtual channel (PVC). 
     For the embodiment of FIG. 1, a separate management link  42  connects the customer premise equipment  20  of each site  12  to the management site  16 . It will be understood that a single management link  42  may be used to connect a plurality of items of customer premise equipment  20  from the same or different sites  20  to the management site  16  as long as the Internet Protocol addresses connected through link  42  are unique. Thus, for example, if a customer assigns its premise equipment  20  Internet Protocol addresses that are internally unique, then a single management link  42  may be used to connect that customer&#39;s equipment to the management site  16 . Similarly, if divisions or segments of the customer&#39;s equipment or groups of customers have Internet Protocol addresses that are unique among themselves, the customer premise equipment  20  for those divisions, segments, or groups may be connected to the management site  16  through a single management link  42 . 
     The management site  16  includes a switch  50 , a plurality of customer servers  52 A,  52 B, and  52 C, a local area network  54 , and a management station  56 . The switch  50  includes a separate input  58  for each management link  42 . The switch  50  routes traffic based on the input  58  or link  42  from which the traffic is received. Thus, traffic received from the customer premise equipment  20  of customer site  12 A is routed through the switch  50  to the customer server  52 A. Similarly, traffic received from the customer premise equipment  20  of customer site  12 B is routed through the switch  50  to the customer server  52 B and traffic received from the customer premise equipment  20  of customer site  12 C is routed through the switch  50  to the customer server  52 C. The switch  50  may be a digital cross connect switch, a router with static routing, or other device operable to direct traffic based upon the input or line from which the traffic was received. 
     For the embodiment of FIG. 1, the switch  50  is connected to the servers  52  via multiple ports  60 . This allows traffic to be directed from a management link  42  to a server  52  without additional addressing by the switch  50 . Alternatively, the switch  50  may be connected to the servers  52  via the local area network  54 . In this embodiment, the switch  50  addresses traffic to the servers  52  on the local area network  54  based on the input  58  or link  42  on which the traffic was received. 
     The customer servers  52  each include a memory  62  for storing downloaded traffic. In one embodiment, performance data for the customer premise equipment  20  of a customer site  12  may be automatically downloaded and stored in the memory  62  of the customer server  52  at scheduled intervals. In this embodiment, for example, the performance data may be downloaded every  24  hours. Additionally, the performance data may be downloaded upon request from the management station  56 . 
     The management station  56  is a work station or other suitable device operable to access and manage the client sites  12 . The management station  56  is connected to this switch via the local area network  54 . The local area network  54  may be an Ethernet or other suitable local network. 
     The management station  56  uses addresses associated with the switch inputs  58  to distinguish and thus individually access the customer premise equipment  20  of the customer sites  12 . An address is associated with an input  58  when it is, in whole or in part, the address of the input  58 , is based upon the input address, or capable of being traced back to or related to the input  58 . Using addresses associated with the switch inputs  58 , the management station  56  is able to indirectly access customer premise equipment having a same Internet Protocol address. Accordingly, customer sites  12  can be managed without the time consuming and costly task of maintaining unique Internet Protocol addresses for each item of customer premise equipment  20 . 
     FIG. 2 illustrates details of the management network  46 . As previously described, the management network  46  includes robust maintenance links  42  that provide communication between the client and management sites  12  and  16 . 
     Referring to FIG. 2, the management network  46  includes a plurality of routers  60  connected by network trunks  62 . Primary embedded channels  64  and secondary embedded channels  66  are defined in the network trunks  62 . In one embodiment, the network trunks  62  are T 1 s and the embedded channels  64  and  66  are private virtual channels. The private virtual channels  64  and  66  provide what appears to be dedicated lines without the cost associated with such lines. The private virtual channels  64  and  66  follow a predefined path between routers  60  and other equipment of the management network  46 . In accordance private virtual channel standards, data is transmitted in accordance with backward and forward congestion protocols. 
     The primary private virtual channel  64  carries management channel traffic between the customer and client sites  12  and  16  in normal operation. The secondary private virtual channel  66  carries the channel traffic between the customer and management sites  12  and  16  in the event of a fault condition on the primary embedded channel  64 . Accordingly, communications, and thus management, of the customer premise equipment  20  is maintained even in the presence of a fault on a management link  42 . 
     FIG. 3 illustrates a method of automatic line protection switching between the primary and secondary private virtual channels  64  and  66  of the management network  46 . The method is independently conducted by the routers  60  at each end of the primary and secondary private virtual channels. As a result, the routers  60  independently switch between the primary and secondary private virtual channels  64  and  66  in unison and without the communication of private virtual channel fault messages. 
     Referring to FIG. 3, in a normal state  70  traffic is transmitted and received between transmit and receive nodes via the primary private virtual channel  64 . The node may be routers, switches, hooks, bridges or other equipment capable of selectively directing traffic in the management network  46 . In the normal state  70 , each node independently monitors a check sum value of the primary private virtual channel  64 . When a check sum value for the primary private virtual channel  64  is received, state  70  leads to step  72 . At step  72 , the node determines a bit error rate (BER) for the primary private virtual channel  64  based on the check sum value for the channel  64 . Next, at decisional step  74 , the node determines if the bit error rate is below 10 −6 . If the bit error rate is not below 10 −6 , then the No branch of decisional step  74  returns to normal state  70 . If the bit error rate is below 10 −6 , then a fault condition exists on the primary private virtual channel  64  and the Yes branch of decisional step  74  leads to step  76 . At step  76 , the node switches from the primary private virtual channel  64  to the secondary private virtual channel  66 . Step  76  leads to fault state  78  in which traffic is transmitted and received via the secondary private virtual channel  66 . 
     Returning to normal state  70 , each node also independently monitors the bit error rate of the network trunk  62 . The bit error rate may be independently determined by each node based on a check sum value or may be provided in accordance with trunk transmission protocol. In response to receiving the bit error rate of the network trunk  62 , state  70  leads to decisional step  80 . At decisional step  80 , the node determines if the bit error rate for the network trunk  62  is below 10 −6 . If the bit error rate is not below 10 −6 , the No branch of decisional step  80  returns to normal state  70 . If the bit error rate of the network trunk  62  is below 10 −6 , a fault condition exists on the network trunk  62  and the Yes branch of decisional step  80  leads to step  76 . As previously described at step  76 , the node switches from the primary private virtual channel  64  to the secondary private virtual channel  66 . Next, at the fault state  78 , traffic is transmitted and received via the secondary private virtual channel  66 . 
     In the default state  78 , each node continues to monitor the network trunk  62  and the primary private virtual channel  64  for a non fault condition. In response to receiving a bit error rate for the network trunk  62  carrying the primary private virtual channel  64 , fault state  76  leads to decisional step  82 . At decisional step  82 , the node determines if the bit error rate for the network trunk  62  is above 10 −4 . If the bit error rate is not above 10 −4 , then a fault condition continues to exist within the network trunk  62  and the No branch of decisional step  82  returns to fault state  78 . If the bit error rate of the network trunk  62  is above 10 −4 , then a non fault condition exits in the network trunk  62  and the Yes branch of decisional branch  82  leads to step  84 . 
     At step  84 , the node receives a check sum value for the primary private virtual channel  64 . Proceeding to step  86 , the node determines the bit error rate for the primary private virtual channel  64  based on the check sum value. Next, at step  88 , the node determines if the bit error rate for the primary private virtual channel  64  is above 10 −4 . If the bit error rate for the primary private virtual channel  64  is not above 10 −4 , then a fault condition continues to exist in the primary private virtual channel  64  and the No branch of decisional step  88  returns to the fault state  78 . If the bit error rate of the primary private virtual channel  64  is above 10 −4 , then a non fault condition exists in the primary private virtual channel  64  and the Yes branch of decisional step  88  leads to step  90 . At step  90 , the node switches from the secondary primary private virtual channel  66  to the primary private virtual channel  64 . Step  90  leads to normal state  70  in which traffic is transmitted and received on the primary private virtual channel  64 . 
     Thus, each node independently and in unison switches between the primary and secondary private virtual channels  64  and  66  in response to the same fault and non fault conditions. The fault and non fault conditions may be any suitable condition of the network trunk and/or private virtual or other embedded channel that can be obtained or determined by the nodes. In this way, automatic line protection switching is provided for private virtual channels independent of protection for network trunks. 
     Although the present invention has been described with several embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present invention encompass such changes and modifications as fall within the scope of the appended claims.