Abstract:
A method and system for priority based (1:1) n  Ethernet protection. The method and system includes assigning a priority to each of the flows associated with a working path. Upon fail of one or more of the working paths checking available bandwidth and priority of the flows. Once the request is complete, switching one or more flows to the protection path based on at least the priority of the flow, the bandwidth of the working path and the available bandwidth on the protection path. If a newly failed working path has a higher priority flow then dropping a flow from the protection path to a pending state. Once a working path has recovered, reverting the flow back to the working path and possibly admitting pending data to the protection path if the bandwidth and prioritization requirements are met.

Description:
TECHNICAL FIELD OF THE DISCLOSURE 
       [0001]    The present disclosure relates generally to Ethernet networks and, more particularly, to a method and system to protect several working Ethernet flows that have a common protection path by assigning priority to each of the working flows. 
       BACKGROUND 
       [0002]    Telecommunications systems and data communication networks use Ethernet networks to rapidly convey large amounts of information between remote points. In an Ethernet network, information is conveyed in the form of frames through fiber optic electrical connections, for example. Ethernet networks can be used to implement Local Area Networks (LANs). Virtual Local Area Networks (Vans) can group, physically disparate network elements together to operate with a common set of requirements as if they were attached to the same domain. 
         [0003]    An Ethernet network handles a large amount of data from multiple points in the network. The bandwidth of a network is finite and determines the amount of data that can be communicated at any given time. Common issues with networks are loss of data or connection due to a line failure. For example, a service provider may experience disruptions in data transmission or slow downs of data transmission to multiple clients. The disruption of data flow may impact business costs due to lost working time. As technology continues to improve, clients expect a high level of service and minimal loss of data. 
         [0004]    A current solution to the issues of lost data and the need for a higher level of service is to provide an alternate path, called a protection path, that is available for re-routing data when there is a failure in the primary path, called a working path. Disadvantages of the protection path are inefficient use of network bandwidth, lack of predictability of which data path or flow will be on the protection path during a multiple fail scenario, no opportunities to optimize bandwidth of the network, and limited ability of service providers to offer improved service level agreements (SLA). 
       SUMMARY 
       [0005]    In accordance with a particular embodiment of the present disclosure, a method and system for priority based Ethernet protection is presented. The method and system may include protecting multiple working Ethernet flows which share a common protection path by assigning a priority to each of the working flows on each of the working paths. The method and system may further include determining the available bandwidth on a protection path upon failure of the working paths. The method and system may additionally include determining the priority of the flows on the failed working paths. Moreover, the method and system may include switching two or more flows to the protection paths based at least on the priority of the flows, the bandwidth of the flows in the working path and the available bandwidth on the protection path. 
         [0006]    Technical advantages of one or more embodiments of the present disclosure may include the ability to assign priorities to flows associated with the working paths of Ethernet connections. If service providers or IT departments can assign priorities to the flows, then during multiple working path failure conditions there will be no interruptions of critical data transmissions. 
         [0007]    Technical advantages of one or more embodiments of the present disclosure may also include the ability to service multiple working path failures. In particular embodiments, if the bandwidth of the protection path is sufficient, the traffic on more than one path can be assigned to the protection path during multiple failure conditions. The priority of the flow and its associated bandwidth may determine whether the flow on the failed working path will be switched to the protection path. Also, having the flows of multiple failed working paths switched to the protection path may also allow for optimization of bandwidth usage. 
         [0008]    Technical advantages of one or more embodiments of the present disclosure may also allow for an improved business model and level of service for clients. A service provider may be able to offer multiple levels of service through assigning priorities to flows and servicing multiple working path failures. They may be able to charge clients for this higher level of service and a service provider could see increased profits and clients could ensure a certain level of service. In addition, in an office environment, critical data systems would receive uninterrupted service. 
         [0009]    It will be understood that the various embodiments of the present disclosure may include some, all, or none of the enumerated technical advantages. In addition, other technical advantages of the present disclosure may be readily apparent to one skilled in the art from the figures, description and claims included herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    For a more complete understanding of the present disclosure and its features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which: 
           [0011]      FIG. 1  is a block diagram illustrating a (1:1) n  protection architecture in a network; 
           [0012]      FIG. 2  is an illustration of the Automatic Protection Switching (APS) Frame used in the protection architecture of  FIG. 1 ; 
           [0013]      FIG. 3  is a block diagram illustrating an embodiment for a priority based (1:1) n  protection scheme in a network, according to a particular embodiment of the present disclosure; 
           [0014]      FIG. 4  is an illustration of an example APS Frame for according to a particular embodiment of the present disclosure; 
           [0015]      FIG. 5  is an illustration of another example APS Frame according to a particular embodiment of the present disclosure; 
           [0016]      FIG. 6  is a block diagram illustrating an example of the network of  FIG. 3  when a single working path fails, according to a particular embodiment of the present disclosure; 
           [0017]      FIG. 7  is a block diagram illustrating the operation of the network of  FIG. 3  when a second working path fails, according to a particular embodiment of the present disclosure; 
           [0018]      FIG. 8  is a block diagram illustrating the operation of the network of  FIG. 3  when a third working path fails but its flow is not admitted to the protection path, according to a particular embodiment of the present disclosure; 
           [0019]      FIG. 9  is a block diagram illustrating the operation of the network of  FIG. 3  when a working path recovers and a pending flow from a previous working path failure is admitted according, to a particular embodiment of the present disclosure; 
           [0020]      FIG. 10  is a block diagram illustrating the operation of the network of  FIG. 3  when a working path with a higher priority flow fails and a lower priority flow is dropped, according to a particular embodiment of the present disclosure; and 
           [0021]      FIG. 11  is a block diagram illustrating an example method for protection switching, according to a particular embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]      FIG. 1  is an example of a current (1:1) n  protection architecture in a network as described in the ITU-T G808.1 specification. A network may include a plurality of network elements configured to transmit data on a plurality of working paths coupled to the network elements. In certain embodiments, the network includes network elements or nodes  100  that are communicatively coupled via working paths  120  and protection path  150 . However, any suitable configuration of any suitable number of network elements  100  may create the network. The network elements  100  may be located in similar or geographically disparate locations. Although the network is shown as a logical point-to-point network, the network may also be configured as a ring network, mesh network, or any other suitable network or combination of networks. 
         [0023]    Network elements may be coupled via optical fiber, an Ethernet cable, a WiFi signal, or other suitable medium. Network elements  100   a  and  100   b  may exchange data transmissions (flows), Continuity Check Messages (CCM) and Automatic 
         [0024]    Protection Switching (APS) signals. CCMs are uni-directional, broadcast messages that provide a means to check connectivity of paths in a network. Each working path and protection path has a unique CCM signal between network elements  100 . The APS signal is a frame that contains information specific to the protection scheme and to switching data from the working path to the protection path. The APS signal may be transmitted periodically on the protection path  150  during normal operation. When a working path failure occurs, the APS frame may be immediately transmitted between the network elements bounding the path. When there is a need to switch a flow  110  from a working path  120  to a protection path  150 , the APS frame may perform the handshaking between network elements  100 . In addition, each working path has an associated flow. Flows  110  are the traffic or data transmitted on the working paths  120  and protection path  150 . Such traffic may comprise optical or electrical signals configured to encode audio, video, textual, and/or any other suitable data. In addition, each working path has a finite bandwidth. In the current example, working path  120   a  has 400 MB, working path  120   b  has 200 MB, working path  120   c  has 100 MB and working path  120   d  has 100 MB. Protection path  150  has a bandwidth equal to the bandwidth of the largest working path bandwidth that it is protecting. In this example, the protection path  150  has bandwidth of at least 400 MB, which is the bandwidth of highest bandwidth working path  120   a.  However, the bandwidth of each working path and the protection path may be any value suitable to meet the data transmission needs. Additionally, in the network, only one working path may be protected at a time. In the case of multiple working path failures, certain flows will not be protected. 
         [0025]      FIG. 2  is an illustration of the Automatic Protection Switching (APS) Frame for current protection schemes. Automatic Protection Switching is described in the ITU-T G.8031 specification and further defined in Telcordia GR-253. The ITU-T G.808.1 specification defines a required communication channel called the protection path or protection flow between two network elements. It is separate from the working entity or path and is used to synchronize the two network elements defining the boundaries of the protection path. In the frame shown in the example, the APS specific information is the following: Request/State  300 , Protection Type  310 , Requested Signal  320  and Bridged Signal  330  as defined in the ITU-T G.8031 specification. There is also a Reserved Field  340  that is not currently defined in the ITU-T G.8031 specification. The Request/State  300  is a four bit field which indicates the type of request in the switching algorithm. For example, the Request/State  300  may be “Forced Switch” as indicated by  1101  in the field or “Wait to Restore” as indicated by  0101  in the field. The Protection Type  310  designates A, B, D or R which are defined as follows: A=APS or not, B=1:1 or 1+1 protection algorithm, D=bi-directional or uni-directional protection paths and R=revertive or not revertive. The Protection Type  310  (A and B bits) indicates to the network if Automatic Protection Switching is active and what type of protection scheme is active. The D bit provides further detail so that the network elements  100  know whether the data flow switched to the protection path is uni-directional or bi-directional. The Requested Signal  320  indicates the request by the near end node to be switched over to the protection path. The Bridged Signal  330  indicates that the signal is switched by the near end node over the protection path. The Requested Signal  320  and the Bridged Signal  330  allow the network elements  100   a  and  100   b  to remain synchronized when switching a flow from a failed working path to the protection path. 
         [0026]    For example, in the current protection scheme as described in  FIGS. 1 and 2 , if a connectivity failure was detected via the CCM signal on a working path, the APS mechanism may activate. An APS frame may be sent between network elements  100  to ensure that each node agrees to switch the traffic or flow from the working path failure to the protection path. For example, network element  100   a  may send an 
         [0027]    APS frame to network element  100   b  that has the “Requested Signal”  320  bit set. Network element  100   b  receives the APS frame and returns an APS frame with the “Requested Signal”  320  bit set. Network element  100   a  responds with another APS frame with both the “Requested Signal”  320  and the “Bridged Signal”  330  set. Network element  100   b  receives the frame and responds with an APS frame with the same bits set. With the appropriate bits in the APS frame set, the network elements  100  are in agreement and the data switch occurs. The CCM signal for the working path with a failure may continue to be monitored. Once the CCM signal restores, a “Wait to Restore” will be set in the APS frame “Request/State”  300  field and the process described above may be repeated but the bits may be un-set instead of set. 
         [0028]      FIG. 3  is a block diagram illustrating an embodiment for a (1:1) n  priority based protection scheme in a network. In the example scheme, multiple working paths may be protected and unique priorities may be assigned to the flows associated with each working path. The network is communicatively coupled via working paths  220  and protection path  250  through network elements  200 . In some embodiments, the working paths grouped with a particular protection path may be defined in the software of network elements  200 . In other embodiments the working paths grouped with a particular protection path may be defined in hardware of network elements  200 . Flows  210  are the data transmitted on the working paths  220 . The working paths  220  in  FIG. 3  have a finite bandwidth and the flows  210  have a unique priority. In the example embodiment, working paths  220  have the following bandwidth and priority: working path  220   a  has 400 MB and Priority  1 , working path  220   b  has 200 MB and Priority  2 , working path  220   c  has 100 MB and Priority  3 , and working path  220   d  has 100 MB and Priority  4 . Protection path  250  may have a bandwidth greater than or equal to the sum of the bandwidth of the largest working path bandwidth that it is protecting and the APS frame bandwidth. In this example, the protection path  250  has a bandwidth of 500 MB which is greater than the 400 MB bandwidth of working path  220   a.  In general, the protection path bandwidth may be greater than or equal to the bandwidth of the largest working path. 
         [0029]    The network elements  200   a  and  200   b  shown in  FIG. 3  may be located in similar or geographically disparate locations. The network elements  200   a  and  200   b  may also define the boundaries of the protection path. Network elements  200  may be a switch with a single network card or a distributed switch with multiple network cards. The network cards in network elements  200  may have Ethernet ports and processing resources. Within the processing resources of network elements  200 , the configuration of the network may be defined. Each network element may have the working paths and the protection path defined as well as the bandwidth of each path stored. Also an APS State Machine Module (SMM), a Configuration Module and a Flow Admission Module (FAM), not explicitly shown, may be present on the processing resources within the network elements. The APS State Machine Module (SMM) and Flow Admission Module (FAM) are the mechanism for supporting traffic switching from the working path to the protection path. The Configuration Module assigns the priority of the flow on the working path. The SMM is the state machine that facilitates sending the APS frame between network elements negotiating a switch to the protection path. The FAM tracks the status of the protection path in terms of priority and bandwidth and stores the bandwidth of the working paths grouped with the protection path. The FAM may be similar to a Connection Admission Control (CAC) algorithm that determines whether connections should be allowed based on sufficient resource availability. These modules assess the bandwidth and priority and control the switching of the flow(s)  210  from the failing working path(s)  220  to the protection path  250 . In addition, in this embodiment, the FAM and SMM may facilitate protecting more than one working path at a time. When there are multiple working path failures, for example, assigned priorities and available/required bandwidth may be used as decision criteria in the FAM when deciding which flow to protect. When multiple failures occur during the same time period, the flows  210  from the working paths  220  may be admitted to the protection path  250  in decreasing order of priority. If the bandwidth of the protection path  250  is fully utilized, the priority of the flow from the newly failed working path  220  may be used to pre-empt existing lower priority flows on the protection path  250 . When a working path  220  with the higher priority flow is restored, then the lower priority flow from working paths  220  with the failure will be given an opportunity to have the flow  210  be admitted on to the protection path  250 , provided the required bandwidth is available. Once the SMM has determined the traffic to allow on the protection path, the SMM will initiate APS frames to begin the switch of flows  210  from the failed working path  220  to the protection path  250 . This will be described in further detail in the descriptions of the Figures below. 
         [0030]    Also shown in  FIG. 3 , the working paths  220  may have a Continuity Check Message (CCM) to indicate current status. The CCM is a standard Ethernet mechanism as described in IEEE 802.1ag that detects and signals connectivity failures, as described in  FIG. 1 . For example, the CCM signal may be monitored and generated by a Fault Detection Module (FDM), not explicitly shown, that may be present on the processing resources of the network elements  200 . A CCM signal may be broadcast, as an example, at a periodic rate of 3.3 ms. The CCM may be monitored to determine if a flow  210  needs to be switched to the protection path  250 . A failure of the CCM signal may be defined as a minimum of three missed CCM broadcasts. The APS signals for each working path  220  are transmitted by the APS State Machine Module (SMM) on the protection path  250  when their associated working path has failed. The APS signals in the example embodiment are based on the ITU-T G.8031 specification, as illustrated in  FIG. 2 . In the example embodiment, the standard 
         [0031]    APS signal may be augmented to include information that creates an Flow Identifier (Flow ID) for a flow associated with a particular working path, as described below in conjunction with  FIG. 4 . The APS frame for each flow  210  is transmitted on the protection path  250 . 
         [0032]      FIG. 4  is an illustration of an example APS frame, according to a particular embodiment of the present disclosure. The 4th byte in the APS specific information may be used to carry the Flow ID  440  to represent a specific flow. The Flow ID  440  may also be used to define the priority of the flow. To achieve priority based (1:1) n  architecture for a network, the following fields in the APS specific section of the frame may be set to the following for the Protection Type  410 : A=APS, B=1:1, D=Bi-directional, R=Revertive. The A bit shows that the APS mechanism will be used in the protection scheme (1:1) as indicated in bit B. The D bit set as bi-directional indicates that a working path failure will have both directions of data flow switched to the protection path. The R bit indicates that if a flow is present on a protection path, it will return to the working path if the path is restored. The Requested Signal  420  and the Bridged Signal  430  may be a 0 or 1 to indicate a request and a transition to the protection path. These two bits may be used as a handshaking mechanism to allow to nodes of a network to negotiate switching a flow from the working path to the protection path. 
         [0033]      FIG. 5  is an illustration of the APS Frame for communicating APS information for multiple flows, according to a particular embodiment of the present disclosure. If the Type-Length-Value (TLV) Offset  500  and End TLV  510  portion of the frame is utilized, then multiple APS signal information may be transmitted together on the protection path to facilitate multiple flows sharing a protection path. The TLV Offset  500  separates the APS frames for a specific flow. Within each APS frame the Flow ID  540  may identify the flow associated with this frame. The End TLV  510  field indicates that end of the grouping of APS frames. In the embodiment shown in  FIG. 5 , four working paths share a protection path. The APS signals associated with each flow may be transmitted periodically on the protection path. When a working path fails, the APS frame associated with its flow may have the appropriate bits set to begin the handshake mechanism between network elements. The non-failing working path APS frames may be unaffected. 
         [0034]      FIG. 6  is a block diagram illustrating an example of the network of  FIG. 3  when a single working path fails according to a particular embodiment of the present disclosure. In this example, a failure occurs in working path  220   c  as indicated by a loss of CCM signal. The APS mechanism in the SMM is activated and communicates with the FAM to determine if there is bandwidth available. The FAM determines that working path  220   c  has 100 MB of bandwidth. Since this is less than the 500 MB bandwidth of the protection path and no other traffic is on the protection path, the FAM allows the flow  210   c  from working path  220   c  to switch to the protection path  250  regardless of the priority reflected in its APS signal. The FAM communicates to the SMM that the switch may occur. The SMM sends an APS frame from network element  200   a  to network element  200   b  that has the “Requested Signal” bit set. Network element  200   b  receives the APS frame and returns an APS frame with the “Requested Signal” bit set. Network element  200   a  responds with another APS frame with both the “Requested Signal” and the “Bridged Signal” set. Network element  200   b  receives the frame and responds with an APS frame with the same bits set. With the appropriate bits in the APS frame set, the network elements  200  are in agreement and the data switch occurs. Now the available bandwidth on the protection path  250  is 400 MB. In this embodiment, the protection scheme is revertive therefore the CCM signal on the working path  220   c  is constantly monitored. If the CCM is restored, thus indicating recovery of the working path, then the traffic would return to the working path. 
         [0035]      FIG. 7  continues illustrating the example of the network of  FIG. 6  when a second working path fails according to a particular embodiment of the present disclosure. As shown in  FIG. 6 , working path  220   c  has already failed and the flow  210   c  has been admitted to the protection path  250 . In the example in  FIG. 7 , a failure now occurs in working path flow  220   d  as indicated by a loss of CCM signal. The FAM determines that working path  220   d  has 100 MB of bandwidth and the protection path has 400 MB of available bandwidth. Since the protection path bandwidth is sufficient (400 MB &gt;100 MB), the FAM allows working path  220   d  to be admitted to the protection path  250  regardless of the priority. The FAM indicates to the SMM to initiate the switch of traffic from the failed working path to the protection path. The traffic switch occurs with the APS frames as described in  FIG. 6 . There is now 300 MB of available bandwidth on protection path  250 . 
         [0036]      FIG. 8  continues illustrating the example of the network of  FIG. 6  when a third working path fails according to a particular embodiment of the present disclosure. As shown in  FIGS. 6 and 7 , working path  220   c  and working path  220   d  have already failed and been admitted to the protection path  250 . There is 300 MB of available bandwidth on the protection path  250  when a loss of CCM signal indicates a failure occurred in working path  220   a.  The SMM sends a request to the FAM to switch. The FAM determines that working path  220   a  has a 400 MB bandwidth requirement which is larger than the available bandwidth (300 MB) of the protection path  250 . The FAM compares the priorities of the traffic from working paths  220   c,    220   d  and  220   a  and determines that the new failure on working path  220   a  has the lowest priority signal so it is not admitted to the protection path  250 . The 
         [0037]    FAM denies the switch and places the working path failure in the pending state for the protection path. The SMM sends an APS frame between network elements  200   a  and  200   b  noting the denial in the “Request/State” field. In addition, the flow  210   a  from working path  220   a  is not transmitted during the time it is in the pending state. The protection architecture does not track or maintain any knowledge of the data while the working path is in the fail condition. The CCM signal may be monitored to determine whether the working path is repaired and monitor the availability of the protection path in order to create a link for data transmission. 
         [0038]      FIG. 9  continues illustrating the example of the network of  FIG. 10  when a working path recovers and a pending flow from a previous failed working path is admitted to the protection path according to a particular embodiment of the present disclosure. As shown in  FIGS. 6 ,  7  and  8 , working path  220   c  and working path  220   d  have already failed and their flows,  210   c  and  210   d  respectively, have been admitted to the protection path  250 . The flow&#39;s  210   a  admittance to the protection path  250  is pending due to insufficient bandwidth and lower priority. As discussed above, in this embodiment, the protection scheme is revertive therefore the CCM signal on the working path  220   c  may be constantly monitored. The FAM recognizes that working path  220   c  has recovered and communicates to the SMM to initiate the traffic switch back to the working path. The SMM sends an APS frame with “Wait to Restore” set in the “Request/State” field between network elements  200 . Network element  200   a  sends an APS frame to network element  200   b  with the Requested Signal field set to zero. Network element  200   b  responds with an APS frame with the Bridged Signal and Requested Signal set to zero. Working path  220   c  is now transmitting flow  210   c.    
         [0039]    The FAM recalculates the available bandwidth on the protection path and determines that there is now 400 MB of bandwidth available. Prior to working path  220   c  recovering, there was 300 MB of available bandwidth on the protection path  250  and, since flow  210   c  required 100 MB of bandwidth, there is now 400 MB of bandwidth available on the protection path  250 . The FAM determines that the pending data from working path  220   a  can now be admitted since there is sufficient bandwidth on the protection path and no other higher priority fails pending. Once flow  210   a  is admitted, there is zero bandwidth available on the protection path  250 . 
         [0040]    The FAM notifies the SMM to begin switching the traffic of working path  220   a  to the protection path. The switch of flow  210   a  to the protection path  250  occurs as described in the figures above. 
         [0041]      FIG. 10  continues illustrating the example of the network of  FIG. 9  when a working path with a higher priority flow fails and a lower priority flow is dropped from the protection path according to a particular embodiment of the present disclosure. As shown in  FIGS. 6-10 , working path  220   c  and working path  220   d  have already failed and their respective flows have been admitted to the protection path  250 . Working path  220   a  was pending until working path  220   c  recovered and then flow  210   a  was admitted to the protection path. There is zero available bandwidth when working path  220   b  fails as indicated by its CCM signal. The FAM determines that flow  210   b  has a higher priority than flow  210   a  which is already transmitting on the protection path. The FAM also determines that if flow  210   a  is dropped, there will be sufficient bandwidth for flow  210   b.  The FAM signals the SMM to initiate dropping flow  210   a  from the protection path  250  and admitting flow  210   b.  There is now 200 MB of available 500 MB bandwidth on the protection path  250  since flows 2+3+4 requires a total 200 MB+100 MB+100 MB=300 MB. The SMM initiates the APS mechanism and sends APS frames on the protection path  250  for working path  220   a  between network elements  200  with the appropriate bits in the “Request State” field set as described in the ITU-T G.8031 specification. The SMM notes that working path  220   a  is not functional so it will be in the pending state. Flow  210   b  will be admitted to the protection path with the APS handshaking mechanism described above. 
         [0042]      FIG. 11  is a block diagram illustrating an example method for protection switching, according to a particular embodiment of the present disclosure. In step  300 , the working paths are functional and monitored periodically to determine if there is a failure. In step  304 , if one or more failures have occurred there is a check for sufficient bandwidth. If there is sufficient bandwidth, then the flow(s) are switched to the protection path in step  306 . In step  307 , the available bandwidth on the protected path is recalculated. In step  308 , the state of the failed working paths is monitored. If the failed path recovers, then the flow reverts back to the working path in step  310 . In step  311 , the amount of available bandwidth on the protected path may be updated. In addition at step  311 , after the available bandwidth is updated, the pending flows will be checked in step  316 . If there are pending flows in  316 , then the process will continue at step  304 . If there is not sufficient bandwidth in  304 , then in step  312 , the priority of the flows is determined. In step  314 , if the newly failed flow is higher priority than one or more of flows currently on the protection path, determine in step  318  if dropping one or more of them provides sufficient bandwidth for the higher priority failed flow. If yes, then the lower priority failures are dropped in step  320  and placed in the pending queue to make room for the higher priority failed flow and the higher priority flow is switched to the protection path in step  306 . If not, the current failure is in the pending state in step  313  and will be monitored in step  316  for admittance to the protection path. In addition at step  314 , if the new failure is not higher priority than the current fails on the protection path, then the latest failure is pending in step  313  until sufficient bandwidth is available as determined in step  304 . 
         [0043]    Although  FIG. 11  discloses a particular number of steps to be taken with respect to the method of implementing priority based Ethernet protection, the steps may be executed with more or fewer steps than those depicted in  FIG. 11 . In addition, although  FIGS. 5 through 10  disclose a certain order of steps that may be taken with respect to the method implementing priority based Ethernet protection, the steps comprising the method of implementing priority based Ethernet protection may be completed in any suitable order. 
         [0044]    Although the present disclosure 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 disclosure encompass such changes and modifications as fall within the scope of the appended claims. For example, modifications, additions, or omissions may be made to the working paths, switches, signals and network described without departing from the scope of the disclosure.