IP multi-homing

Abstract

A method and system for providing a customer network with high speed access to a carrier network is provided. The system comprises an access device for providing a communication path for the customer network, a first concentrator device that is operable to establish a communication path with the carrier network, and a second concentrator device that is operable to establish a communication path with the carrier network. The access device is operable to receive data traffic from the customer network and to forward the data traffic within the system. The access device and the first concentrator device cooperate to form a first virtual channel for allowing data traffic to flow from the customer network to the carrier network and from the carrier network to the customer network and wherein the first virtual channel is the primary communication channel for the customer network. The access device and the second concentrator device cooperate to form a second virtual channel for allowing data traffic to flow from the customer network to the carrier network and from the carrier network to the customer network and wherein the second virtual channel is a backup communication channel for the customer network. The system is operable to switch the primary communication channel from the first virtual channel to the second virtual channel upon detection of a failure in the first virtual channel.

1 . A method of operating an access device to transmit traffic from a LAN to a WAN in a ring network wherein the ring network comprises a plurality of network nodes, the ring network having at least a first concentrator device, a second concentrator device, and the access device and wherein the access device, the first concentrator device and the second concentrator device are each located at different network nodes, the ring network having a first communication path from a local area network (LAN) to a wide area network (WAN) via the first concentrator device and the access device, the ring network also having a second communication path from the LAN to the WAN via the second concentrator device and the access device, the method comprising the steps of: 
 transmitting upstream traffic on the first communication path and not on the second communication path;    receiving an error detection signal at the access device indicating that an error has been detected on the first communication path; and    operating the access device to transmit upstream traffic on the second communication path after receipt of the error detection signal.    
   
   
       2 . The method according to  claim 1  wherein the receiving step comprises the step of detecting a failure by detecting packet oscillation.  
   
   
       3 . The method according to  claim 1  wherein the access device transmits upstream traffic on the second communication path when one or more of the following conditions are detected: a failure of the first concentrator device is detected, the access device is commanded to transmit upstream traffic on the second communication path, a failure of the communication channel between the first concentrator device and the wide area network is detected, a failure of a backbone router coupled to the first concentrator device is detected, or a failure of a bridge device coupled to the first concentrator device is detected.  
   
   
       4 . The method according to  claim 1  further comprising the step of switching the communication path used for transmitting upstream traffic from the second communication path to the first communication path.  
   
   
       5 . The method according to  claim 4  wherein the access device transmits upstream traffic using the first communication path when one or more of the following conditions are detected: the first concentrator device has recovered from a failure, a recovery of the communication channel between the first concentrator device and the wide area network is detected, a failure of the second concentrator device is detected, the access device is commanded to transmit upstream traffic on the first communication path, a failure of the communication channel between the second concentrator device and the wide area network is detected, a failure of a backbone router coupled to the second concentrator device is detected, or a failure of a bridge device coupled to the second concentrator device is detected.  
   
   
       6 . The method according to  claim 1  wherein the ring network comprises a plurality of network nodes and wherein the access device and one of said first concentrator device and said second concentrator device are located at the same network node as the access device.  
   
   
       7 . An access device for use in a ring network wherein the ring network comprises a plurality of network nodes, the ring network having at least a first concentrator device, a second concentrator device, and the access device and wherein the access device, the first concentrator device and the second concentrator device are each located at different network nodes, the ring network having a first communication path from a local area network (LAN) to a wide area network (WAN) via the first concentrator device and the access device, the ring network also having a second communication path from the LAN to the WAN via the second concentrator device and the access device, the access device comprising: 
 means for causing the access device to transmit upstream traffic on the first communication path and not on the second communication path;    means for receiving an error detection signal at the access device indicating that an error has been detected on the first communication path; and    means for causing the access device to transmit upstream traffic on the second communication path after receipt of the error detection signal.    
   
   
       8 . An access device for use in an optical network having a plurality of network nodes coupled together by one or more optical communication paths wherein a plurality of the network nodes have a concentrator device for directing traffic from one or more of the optical communication paths to a wide area network outside of the optical network and for directing traffic from the wide area network to one or more of the optical communication paths in the optical network, the access device comprising: 
 a first interface that provides a communication link to a local area network;    a second interface that provides a communication link to a plurality of optical network communication paths; and    an access circuit coupled to the first and second interfaces, wherein the access circuit is operable to direct upstream traffic from the local area network to a wide area network via one or more optical network communication paths and is operable to direct downstream traffic from the wide area network to the local area network, the access circuit being operable to direct upstream traffic to the wide area network via a first concentrator device in the optical network and also operable to direct upstream traffic to the wide area network via a second concentrator device in the optical network, the access circuit using one of the first and second concentrator devices as a working concentrator device and the other as a protection concentrator device, the access circuit choosing the second concentrator device as the working concentrator device upon the access circuit being alerted that a failed condition associated with the first concentrator device had been detected.    
   
   
       9 . The access device according to  claim 8  wherein the access device is operable to detect a failed condition with the first concentrator device by detecting packet oscillation in the system.  
   
   
       10 . The access device according to  claim 8  wherein the access device is operable to select the second concentrator device as the working concentrator device when one or more of the follow conditions are detected: a failure of the first concentrator device is detected, the access device is commanded to switch the selection of working and protection concentrator devices, a failure of the communication path between the first concentrator device and the wide area network is detected, a failure of a backbone router coupled to the first concentrator device is detected, or a failure of a bridge device coupled to the first concentrator device is detected.  
   
   
       11 . The access device according to  claim 8  wherein the access device is operable to select the first concentrator device as the working concentrator device and to select the second concentrator device as the protection concentrator device when one or more of the follow conditions are detected: the first concentrator device has recovered from a failure, a recovery of the communication path between the first concentrator device and the wide area network is detected, a failure of the second concentrator device is detected, the access device is commanded to switch the selection of working and protection concentrator devices, a failure of the communication path between the second concentrator device and the wide area network is detected, a failure of a backbone router coupled to the second concentrator device is detected, or a failure of a bridge device coupled to the second concentrator device is detected.