Patent Publication Number: US-7916636-B2

Title: Ring network aggregate rates

Description:
FIELD OF THE INVENTION 
     The present invention relates to packet ring networks and, more particularly, to bandwidth allocation and traffic management thereof. 
     BACKGROUND OF THE INVENTION 
     Managing the data traffic in a ring network, such as an Ethernet Ring, involves two general procedures: determining the applicable bandwidth parameters at each point in the ring; and moderating the actual (real-time) data traffic at each point according to the applicable bandwidth parameters. 
     Bandwidth parameters take into account factors including, but not limited to: Quality of Service (QoS); Class of Service (CoS); Class Type (CT); ringlet (also denoted as “ring side”, being one of: “inner” and “outer”); and failure protection scenario. Moreover, rates are categorized in terms of Committed Information Rate (CIR) and Excess Information Rate (EIR), as well as combinations thereof in cases of shared resources. 
     Moderating the real-time traffic is typically done via hardware modules which detect real-time traffic rates, and which buffer and schedule transmission of data packets according to various prior-art strategies and algorithms. A typical goal of traffic management is to minimize network latency, especially for high-priority classes of service, by versatile utilization of bandwidth resources. At the same time, however, it is also desired to avoid traffic congestion, because this can cause failures in sustaining QoS for certain classes. It is therefore highly desirable to know the details of the available bandwidth distribution in order to moderate real-time traffic efficiently while minimizing the probability of congestion. 
     The available bandwidth distribution (as a function of the factors listed above) typically varies, however, especially in cases of node and/or segment failure. Failure of a single node and/or segment typically has an effect on the available bandwidth throughout the ring, and the effect is typically different from one node to another. 
     Unfortunately, however, when configuring or reconfiguring a network ring, the network elements currently have limited information about the available bandwidth parameters, and therefore cannot configure traffic management in the best way possible. 
     There is thus a need for, and it would be highly advantageous to have, an improved way of dependably determining the available bandwidth parameters of a ring network and thereby providing efficient traffic management functionality to the network elements thereof. This goal is met by the present invention. 
     SUMMARY OF THE INVENTION 
     The present invention provides a functionality and method for determining aggregate bandwidth requirements for an Ethernet ring network, based on a priori knowledge of the ring network, including the topology, path utilization, bandwidth sharing, and the failure protection scenarios of the ring network. It is therefore assumed that the topology and failure scenarios are known a priori, and that a priori primary bandwidth allocation data is available from a resource or agent such as a bandwidth broker. 
     According to embodiments of the present invention, aggregate bandwidth requirements are furnished in an aggregate bandwidth database; only transit bandwidth requirements through each node are determined—add traffic and download traffic are not taken into account; the aggregate bandwidth requirements are separately determined for each node of the ring network; aggregate bandwidth is automatically determined upon configuration or reconfiguration of the ring network; and aggregate bandwidth requirements are determined in a manner that is independent of the actual real-time data traffic rates—i.e., actual real-time data traffic rates do not affect the aggregate bandwidth. The present invention therefore does not require any actual real-time data traffic rate information. 
     The resulting aggregate bandwidth requirements are available for traffic management and configuring the ring network, to improve the operation, efficiency, and Quality of Service. 
     Therefore, according to the present invention there is provided a traffic management functionality for an Ethernet ring network having a plurality of nodes and segments, the traffic management functionality including: (a) a priori knowledge based bandwidth responsive functionality for automatically configuring a set of traffic management parameters at at least one of the plurality of nodes; and (b) a priori knowledge based bandwidth change responsive functionality for automatically reconfiguring the set of traffic management parameters at at least one of the plurality of nodes; (c) the bandwidth responsive functionality and,the bandwidth change responsive functionality being: (d) based on a priori knowledge of available bandwidths of the plurality of nodes and segments; and (e) independent of traffic rates within the Ethernet ring. 
     In addition, according to the present invention there is also provided a method for providing to a traffic management module an aggregate bandwidth database for an Ethernet ring having a plurality of nodes, the method including: (a) obtaining a bandwidth allocation database containing an allocated pass-through bandwidth corresponding to each node of the plurality of nodes; (b) providing an aggregate bandwidth database containing at least one field, the field having at least one value initialized to zero and associated with a predetermined set of keys having at least one key selected from: a Class of Service; a Class Type; a ring side; and a protection scenario; (c) for a given node of the plurality of nodes, aggregating to the at least one value the allocated pass-through bandwidth corresponding to the given node according to a predetermined rule; and (d) furnishing the aggregate bandwidth database to the traffic management module. 
     The present invention will be more fully understood from the following detailed description of the embodiments thereof, taken together with the drawings in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified illustration conceptually showing a ring network, showing a traffic management module and bandwidth responsive functionalities according to an embodiment of the present invention. 
         FIG. 2A  is a simplified illustration conceptually showing a bandwidth responsive functionality according to an embodiment of the present invention. 
         FIG. 2B  is a flowchart illustrating the aggregation procedure according to embodiments of the present invention. 
         FIG. 3  is a simplified illustration conceptually showing the components of an aggregate bandwidth database according to embodiments of the present invention. 
         FIG. 4  is a simplified illustration conceptually showing a non-limiting example of bandwidth responsive functionality for a ring with LSP&#39;s according to an embodiment of the present invention. 
         FIG. 5  is a simplified illustration conceptually showing a non-limiting example of bandwidth responsive functionality for a ring supporting Virtual Private LAN Services (VPLS&#39;s) according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The principles and operation of traffic management functionality and method according to the present invention may be understood with reference to the drawings and the accompanying description. 
       FIG. 1  illustrates a ring network  100 , showing a traffic management module  101 . In addition, according to an embodiment of the present invention there is shown a traffic management functionality  102  which includes a bandwidth responsive functionality  103  and a bandwidth change responsive functionality  105 . In an embodiment of the present invention, traffic management functionality  102  is associated with traffic management module  101 . In a further embodiment of the present invention, traffic management module  101  is associated with ring network  100 . 
     Ring  100  has multiple nodes, including a node A  107 , which is the node containing traffic management module  101  and traffic management functionality  102 . Other nodes contain similar modules and functionalities (not shown). A typical other node is a node B  109 . Also shown are multiple transmission media segments (“segments”), such as a segment  111  denoted as DA; and a segment  113  denoted as CB. Data packets input through a node into the ring constitute what is commonly called “add” traffic, and this is generally known any given node. Data packets which pass through a node from one segment of the ring to another, however, constitute what is commonly called “transit” traffic, and this is generally unknown. 
     In certain embodiments of the present invention, the ring network is an Ethernet ring. 
     A Priori Knowledge Based Functionality 
     According to embodiments of the present invention, functionalities are based on pre-existing information related to bandwidth capacities in a ring network. Certain embodiments of the present invention rely for this on a predetermined bandwidth allocation database, as is typically provided by a Bandwidth Broker (BWB). 
     In particular, certain embodiments of the present invention make no use of actual real-time traffic rates within the ring network, and the functionalities thereof are for automatically configuring traffic management parameters for the ring network in a manner that is independent of the traffic rates in the ring. 
     Bandwidth Responsive Functionality 
     In embodiments of the present invention, traffic management parameters of the ring network are data transmission bandwidths. A non-limiting example of traffic management configuration is the setting of the parameters for a Weighted Fair Quality (WFQ) shaper. 
       FIG. 2A  conceptually illustrates the detailed operation of bandwidth responsive functionality  103  and bandwidth change responsive functionality  105  according to an embodiment of the present invention. According to certain embodiments of the present invention, the detailed operation of bandwidth change responsive functionality  105  is the same as that of bandwidth responsive functionality  103 , but responds specifically to changes in ring bandwidth capacity  202 . Bandwidth responsive functionality  103  responds to conditions including, but not limited to ring setup (or initialization)  204 . 
     The details of response operation according to an embodiment of the present invention are as follows: 
     A loop entry point  203  with a loop exit point  213  defines a procedure which iterates on the ring nodes. For each node, a step  205  initializes the value of an aggregate bandwidth database field  215  to zero. The details of an aggregate bandwidth database  219  and the structure thereof are illustrated in  FIG. 3  and are discussed below. In this discussion, a ring has N nodes: 1, 2, . . . , N, and the node which is currently being iterated at loop entry point  203  is denoted as node i , where 1≦i≦N. 
     Next, a loop entry point  207  with a loop exit point  211  defines a procedure which iterates on the fields of bandwidth allocation database  202  which are applicable to node i . Details of the database fields are also discussed in detail below. It is understood that aggregate bandwidth database field  215  is shown as being representative of a general aggregate bandwidth database  219  field denoted as field j  for the purpose of illustrating the procedure, and does not represent any given field in particular. Specifically, as loop entry point  207  iterates over all values of j for bandwidth allocation database  202 , all applicable fields of aggregate bandwidth database  219  will be updated as provided by predetermined rules  217 . 
     According to certain embodiments of the present invention, it is assumed that bandwidth responsive functionality  103  has access to: the ring reference topology; and a ring-wide database of bandwidth allocations. 
     As is common practice in the field, a ring-wide database of bandwidth allocations  202  is constructed and distributed by a Bandwidth Broker (BWB)  201 . 
     In a step  209 , the bandwidth parameter values in bandwidth allocation database  202  which are associated with the various fields whose bandwidths are applicable to node i  are aggregated to the value of field j    215  in accordance with the rules of a predetermined rule set  217 . 
     Predetermined rule set  217  determines conditions including, but not limited to: whether a parameter value in bandwidth allocation database  202  is aggregated to the value of field j    215  (or not aggregated); and, if so, specifically how a parameter value in bandwidth allocation database  202  is aggregated to the value of field j    215 . 
     The term “predetermined rule” herein denotes a rule based on factors including, but not limited to: network topology; failure scenario; and bandwidth sharing. 
     Although a rule&#39;s structure is predetermined, it is understood that the factors above (network topology, failure scenario, etc.) may change and are therefore determined at the time the rule is applied. This is illustrated in the LSP example presented below. 
     Aggregation 
     The terms “aggregate”, “aggregated”, and related forms herein denote the inclusion of a parameter value into a collective overall amount. Depending on the predetermined rule in effect, aggregation is performed in ways including, but not limited to: addition; and selecting the greater (or maximum) of two or more values. 
     The LSP example given below shows the application of some predetermined rules. 
     Bandwidth Sharing 
     Elements of a ring can be shared among different paths, and, according to embodiments of the present invention, this case is taken into account by the predetermined rules for aggregating bandwidth capacity. As illustrated in  FIG. 2B , at a decision point  251 , it is determined whether the bandwidth allocations are shared. If the allocations are not shared, in a step  253  the absolute values of the bandwidths are added. If the allocations are shared, in a step  255  the maximum bandwidth is selected. (This is illustrated in the LSP example below, for paths LSP 1  and LSP 3 .) 
     After iteration loop  203  has iterated all applicable nodes, aggregate bandwidth database  219  contains the aggregate bandwidth data for the ring. In embodiments of the present invention, an application can then use this data for ring management or analysis. A non-limiting example of an application is a traffic management module  221 , which provides traffic management functionality for an Ethernet ring network. 
     In an embodiment of the present invention, the application is external to the bandwidth responsive functionality. In another embodiment of the present invention, the application and the bandwidth responsive functionality are contained in a common hardware, software, or hardware/software module. In yet another embodiment of the present invention, the bandwidth responsive functionality contains the application. In a further embodiment of the present invention, the application contains the bandwidth responsive functionality. In a still further embodiment of the present invention, the functionality is contained within a ring network, within a node thereof, or within a network entity or network element (NE) thereof. 
     Aggregate Bandwidth Database 
     An aggregate bandwidth database (such as aggregate bandwidth database  219  in  FIG. 2A ) is produced by a bandwidth responsive functionality according to embodiments of the present invention.  FIG. 3  conceptually illustrates the basic structure of aggregate bandwidth database  219 . 
     The term “database” herein denotes any data structure, or part thereof, which is arranged according to a schema for storing and retrieving at least one data value organized by at least one key and contained in machine-readable data storage of any kind, including, but not limited to: computer memory, RAM, ROM, and the like; magnetic and optical storage, and the like; flash memory storage; computer and network data storage devices; or in similar devices, apparatus, or media. 
     In particular, the term “database” is herein expansively construed to include data organized in tabular format, where data values appear in cells arranged in one or more rows and/or one or more columns serving as keys. Representations of databases in table format herein are understood to correspond to data stored in machine-readable devices and media. 
     As shown in  FIG. 3 , field  215  has a value  301  and is selected from other fields in the database by one or more keys, shown in a non-limiting case of a key 1    303 , a key 2    305 , and a key k    307 . 
     Keys for an aggregate bandwidth database according to embodiments of the present invention include, but are not limited to: a Class of Service (such as: High Priority; Expedited Forwarding; Assured Forwarding; Best Effort; and Expedited Forwarding multicast), a Class Type (such as: Real Time; T1 Committed Information Rate (CIR); T1 Excess Information Rate (EIR); T2 Committed Information Rate; and T2 Excess Information Rate); a ring side (Outer side, also referred to as “East ringlet”; and Inner side, also referred to as “West ringlet”); and a protection scenario (such as a normal scenario, where all ring nodes and segments are functioning properly; and a failure scenario, where a particular node and/or segment has failed). 
     In a non-limiting example of the present invention, an aggregate bandwidth database is represented as follows, for a ring having four nodes (“A”, “B”, “C”, and “D”) and four segments (“AB”, “BC”, “CD”, and “DA”): 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Example of an Aggregate Bandwidth Database 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 High 
                 Expedited 
                 Expedited 
                   
                   
               
               
                   
                 Priority 
                 Forwarding 
                 Forwarding 
                 Assured Forwarding 
                 Best Effort 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 Real 
                 Multicast 
                 Real 
                 T1- 
                 T2- 
                 Real 
                 T1- 
                 T1- 
                 T2- 
                 T2- 
                 Real 
                 T1- 
                 T2- 
               
               
                   
                 Time 
                 Real Time 
                 Time 
                 CIR 
                 CIR 
                 Time 
                 CIR 
                 EIR 
                 CIR 
                 EIR 
                 Time 
                 EIR 
                 EIR 
               
               
                   
                   
               
            
           
           
               
            
               
                 Normal 
               
               
                 Fail 
               
               
                 AB 
               
               
                 Fail 
               
               
                 BC 
               
               
                 Fail 
               
               
                 CD 
               
               
                 Fail 
               
               
                 DA 
               
               
                   
               
            
           
         
       
     
     The rows and columns of Table 1 are the keys, and the cells are the fields holding the values. The database example shown in Table 1 is initialized and is currently empty (as initialized in step  205  of  FIG. 2A ). An empty cell (or field) is considered to represent a data value of zero, i.e., no bandwidth, no data-carrying capacity. 
     It is emphasized that an aggregate bandwidth database can have additional keys and key values. For example, there are additional classes of Assured Forwarding service than are shown in the non-limiting example of Table 1. 
     Bandwidth Allocation Database 
     A bandwidth allocation database (such as bandwidth allocation database  202  in  FIG. 2A ) contains a priori knowledge for a bandwidth responsive functionality according to embodiments of the present invention. 
     In a non-limiting example, a bandwidth allocation database is represented as follows: 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Example of a Bandwidth Allocation Database 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                 Tunnel 
                 Tunnel 
                 Tunnel 
                 Configured 
                 Prot 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                 ID 
                 Src 
                 Dest 
                 Ringlet 
                 Method 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 D 
                 B 
                 Outer 
                 none 
                 20 
                 40 
                 50 
                 30 
                 40 
               
               
                 2 
                 D 
                 B 
                 Inner 
                 SteerR 
                 30 
                 100 
                 200 
                 50 
                 200 
               
               
                 1 
                 D 
                 B 
                 Inner 
                 SteerR 
                 50 
                 60 
                 70 
                 10 
                 80 
               
               
                 3 
                 C 
                 B 
                 Inner 
                 SteerR 
                 100 
                 200 
                 60 
                 90 
                 10 
               
               
                   
               
            
           
         
       
     
     In this non-limiting example, the database keys include the ID, Source (“Src”) Destination (“Dest”), ringlet, and protection method (“none” for unprotected; “SteerR” for steer-revertive) of a particular path (“Tunnel”). Other keys are also possible. The data values of the fields are in kbps, representing the bandwidth allocations. 
     As is well-known, a bandwidth allocation database of this sort is provided by a Bandwidth Broker (such as Bandwidth Broker  201  in  FIG. 2A ), and constitutes a priori information about a ring network which is independent of the actual real-time traffic rates of the network. 
     Protection Scenarios 
     Ring networks in general offer a number of different failure recovery mechanism broadly classified as either wrapping or steering. Certain embodiments of the present invention recognize two protection scenarios: non-protected, and steer-revertive protected. In the non-protected case, if a failure occurs on the path designated for the service, then the service itself unconditionally fails. In the case of steer-revertive protection, the ring is temporarily reconfigured to route the traffic through alternative segments and nodes around the failure. 
     General Predetermined Rules 
     According to embodiments of the present invention, general predetermined rules provide for excluding traffic that is not transit traffic:
         Traffic that is added at a source node is not aggregated at that node.   Traffic that is dropped at a destination node is not considered in computing aggregate rates.       

     Predetermined Rules for LSP Aggregation 
     According to an embodiment of the present invention, predetermined rules for LSP rate aggregation include:
         The LSP normal bandwidths are aggregated for a node only when the LSP normally passes through that node (i.e., when there is no failure in the ring).   In the case of an unprotected LSP, the LSP bandwidths for cases of segment failure are not aggregated for a node when the LSP does not pass through that node.   In case of an LSP that is “steer revertive”, the LSP bandwidths for cases of segment failure are aggregated as follows:
           If the LSP is steered through a node, the relevant LSP protection bandwidths (for CoS and CT) are aggregated for that node.   If the LSP is steered and does not pass through a node, the LSP protection bandwidths are not aggregated for that node.   For a node in the LSP&#39;s normal path, for segment failure that is not in the LSP&#39;s normal path, only the LSP&#39;s normal rate bandwidths (for CoS and CT) are aggregated for that node.   
               

     LSP Example 
     A non-limiting example is illustrated in  FIG. 4 . A ring network  400  has a node “A”  401 , a node “B”  403 , a node “C”  405 , and a node “D”  407 . 
     A label switched path (LSP), denoted as LSP 1   409  has node “D”  407  as a source and node “B”  403  as a destination. LSP&#39;s are unidirectional, and LSP 1   409  is directed through node “A”  401  via an outer ringlet  417 . 
     (It is noted that an LSP is sometimes referred to as a “tunnel” in Multi-Protocol Label Switching, and the term “tunnel” is also used herein with reference to LSP&#39;s. In addition, the term “path” is herein expansively construed to denote any data route over one or more segments of a network. A path having more than one segment also involves one or more nodes connecting the segments.) 
     Another LSP, denoted as LSP 2   411  also has node “D”  407  as a source and node “B”  403  as a destination. LSP 2   411 , however, is directed through node “C”  405  via an inner ringlet  419 . 
     Still another LSP, denoted as LSP 3   413  also has node “D”  407  as a source and node “B”  403  as a destination. Like LSP 2   411 , LSP 3   413  is directed through node “C”  405  via inner ringlet  419 . It is furthermore stipulated that LSP 3  is shared with LSP 1 , as described previously for bandwidth sharing. 
     Yet another LSP, denoted as LSP 4   415  has node “C”  405  as a source and node “B”  403  as a destination, and is also via inner ringlet  419 . 
     In this non-limiting example, an aggregate bandwidth database is generated for node “A”  401 . (To generate a complete aggregate bandwidth database according to certain embodiments of the present invention, a loop would iterate over all the nodes of the ring, as shown by loop entry point  203  in  FIG. 2A .) According to certain embodiments of the present invention, however, a separate RAR application is installed in each individual node, and the aggregate bandwidth database for node “A”  401  is sufficient for the RAR application installed in that node. In these embodiments, node “B”  403  has an aggregate bandwidth database for node “B”  403 , separately generated in a similar fashion. 
     In order to generate the aggregate bandwidth database, the bandwidth allocation database with a priori knowledge of the network is first obtained, such as through a Bandwidth Broker or similar agent. For this non-limiting example, the bandwidth allocation database is shown in Table 3. In addition, the Class of Service for all LSP&#39;s in this non-limiting example is given as Assured Forwarding at T1 rates. 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Bandwidth Allocation Database for LSP Example 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                 Tunnel 
                 Tunnel 
                 Tunnel 
                 Configured 
                 Prot 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                 ID 
                 Src 
                 Dest 
                 Ringlet 
                 Method 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 1 
                 D 
                 B 
                 Outer 
                 none 
                 20 
                 40 
                 50 
                 30 
                 40 
               
               
                 2 
                 D 
                 B 
                 Inner 
                 SteerR 
                 30 
                 100 
                 200 
                 50 
                 200 
               
               
                 1 
                 D 
                 B 
                 Inner 
                 SteerR 
                 50 
                 60 
                 70 
                 10 
                 80 
               
               
                 3 
                 C 
                 B 
                 Inner 
                 SteerR 
                 100 
                 200 
                 60 
                 90 
                 10 
               
               
                   
               
            
           
         
       
     
     As indicated in initialization step  205  of  FIG. 2A , we begin by initializing the aggregate bandwidth database for node “A”  401 . Note that for this particular node, only outer ringlet  417  is of interest, because none of the LSP&#39;s defined for this example make use of inner ringlet  419 , even in a failure scenario. This is not the case in general, however. 
     The initialized aggregate bandwidth database is the same as shown in Table 1 above, and simplified for the Assured Forwarding CoS at T1 rates is: 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Initialized Aggregate Bandwidth Database 
               
               
                 for LSP Example 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
            
               
                   
                 Real 
                 T1- 
                 T1- 
               
               
                   
                 Time 
                 CIR 
                 EIR 
               
               
                   
                   
               
            
           
           
               
               
            
               
                   
                 Normal 
               
               
                   
                 Fail 
               
               
                   
                 AB 
               
               
                   
                 Fail 
               
               
                   
                 BC 
               
               
                   
                 Fail 
               
               
                   
                 CD 
               
               
                   
                 Fail 
               
               
                   
                 DA 
               
               
                   
                   
               
            
           
         
       
     
     Table 4, as well as the other aggregate bandwidth database tables for the LSP example applies only to the outer ringlet of the ring shown in  FIG. 4 . The inner ringlet is not relevant in this example, so there are no values computed for the inner ringlet. 
     As noted previously, an empty cell in table format represents a zero value in the corresponding database field. In addition, this is for outer ringlet  417 . 
     Next, to iterate through the various fields of the Bandwidth Allocation Database (as indicated by loop entry point  207  of  FIG. 2A .), we start first with LSP 1  fields from Table 3 as show in Table 5: 
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 First iteration group in Bandwidth Allocation 
               
               
                 Database for LSP Example 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                   
                 Tunnel 
                 Tunnel 
                 Tunnel 
                 Configured 
                 Prot 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                   
                 ID 
                 Src 
                 Dest 
                 Ringlet 
                 Method 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 LSP1 
                 1 
                 D 
                 B 
                 Outer 
                 none 
                 
                   20 
                 
                 
                   40 
                 
                 
                   50 
                 
                 30 
                 40 
               
               
                   
               
            
           
         
       
     
     The data values shown in Table 5 apply to the “Normal” scenario (i.e., no failures of any part of the ring) of the Aggregate Bandwidth Database as well as the scenarios involving the failure of segment “BC” or segment “CD”. If, however, segment “AB” or segment. “DA” fails, the data from Table 5 does not apply. 
     These data values correspond to an “iteration group”, because there are, in this case, three applicable fields, shown with underlined values in Table 5. After iterating on the applicable fields of Table 5, the Aggregate Bandwidth Database is: 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 Aggregate Bandwidth Database for LSP Example - 
               
               
                 after 1 st  Iteration Group 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
            
               
                   
                 Real 
                 T1- 
                 T1- 
               
               
                   
                 Time 
                 CIR 
                 EIR 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 Normal 
                 
                   20 
                 
                 
                   40 
                 
                 
                   50 
                 
               
               
                   
                 Fail 
               
               
                   
                 AB 
               
               
                   
                 Fail 
                 
                   20 
                 
                 
                   40 
                 
                 
                   50 
                 
               
               
                   
                 BC 
               
               
                   
                 Fail 
                 
                   20 
                 
                 
                   40 
                 
                 
                   50 
                 
               
               
                   
                 CD 
               
               
                   
                 Fail 
               
               
                   
                 DA 
               
               
                   
                   
               
            
           
         
       
     
     In a like manner, the second iteration group uses LSP 2  fields: 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 Second iteration group in Bandwidth Allocation 
               
               
                 Database for LSP Example 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                   
                 Tunnel 
                 Tunnel 
                 Tunnel 
                 Configured 
                 Prot 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                   
                 ID 
                 Src 
                 Dest 
                 Ringlet 
                 Method 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 LSP1 
                 1 
                 D 
                 B 
                 Outer 
                 none 
                 20 
                 40 
                 50 
                 30 
                  40 
               
               
                 LSP2 
                 2 
                 D 
                 B 
                 Inner 
                 SteerR 
                 
                   30 
                 
                 100 
                 200 
                 
                   50 
                 
                 
                   200 
                 
               
               
                   
               
            
           
         
       
     
     In Table 7, fields for LSP 1  are also featured for convenient reference, although they are not used in this iteration. The applicable field values in this iteration are underlined in Table 7. 
     Reference to  FIG. 4  and Table 7 shows that LSP 2  is directed through node “C” via inner ringlet  419 , and therefore under normal circumstances (no failure) does not affect node “A”. Under failure conditions of segment “BC” or segment “CD”, however, traffic of LSP 2  will be routed through node “A”. Thus, after iterating on the applicable fields of Table 7, the Aggregate Bandwidth Database is: 
     
       
         
           
               
             
               
                 TABLE 8 
               
             
            
               
                   
               
               
                 Aggregate Bandwidth Database for LSP Example - 
               
               
                 after 2 nd  Iteration Group 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 Real Time 
                 T1-CIR 
                 T1-EIR 
               
               
                   
                   
               
               
                   
                 Normal 
                 20 
                 40 
                 50 
               
               
                   
                 Fail 
               
               
                   
                 AB 
               
               
                   
                 Fail 
                 20 +  30  = 50 
                 40 +  50  = 90 
                 50 +  200  = 250 
               
               
                   
                 BC 
               
               
                   
                 Fail 
                 20 +  30  = 50 
                 40 +  50  = 90 
                 50 +  200  = 250 
               
               
                   
                 CD 
               
               
                   
                 Fail 
               
               
                   
                 DA 
               
               
                   
                   
               
            
           
         
       
     
     The underlined values in Table 8 are those aggregated from Table 7. 
     Continuing with the third iteration group using LSP 3  fields: 
     
       
         
           
               
             
               
                 TABLE 9 
               
             
            
               
                   
               
               
                 Third iteration group in Bandwidth Allocation 
               
               
                 Database for LSP Example 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                   
                 Tunnel 
                 Tunnel 
                 Tunnel 
                 Configured 
                 Prot 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                   
                 ID 
                 Src 
                 Dest 
                 Ringlet 
                 Method 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 LSP1 
                 1 
                 D 
                 B 
                 Outer 
                 none 
                 20 
                 40 
                 50 
                 30 
                 40 
               
               
                 LSP2 
                 2 
                 D 
                 B 
                 Inner 
                 SteerR 
                 30 
                 100 
                 200 
                 50 
                 200  
               
               
                 LSP3 
                 1 
                 D 
                 B 
                 Inner 
                 SteerR 
                 
                   50 
                 
                 60 
                 70 
                 
                   10 
                 
                 
                   80 
                 
               
               
                   
               
            
           
         
       
     
     As before, in Table 9, fields for LSP 1  and LSP 2  are also featured for convenient reference, although they are not used in this iteration. The applicable field values in this iteration are underlined in Table 9. 
     In the event of a failure of segment “BC” and/or segment “CD”, LSP 3  will be reconfigured to utilize segments “DA” and “AB”. As previously given, LSP 3  is shared with LSP 1 . Therefore, according to the procedure for aggregation as specified previously, the bandwidths thereof are aggregated by taking the maximum of LSP 1  and LSP 3  in the failure cases of interest: 
     
       
         
           
               
             
               
                 TABLE 10 
               
             
            
               
                   
               
               
                 Aggregate Bandwidth Database for LSP Example - 
               
               
                 after 3 rd  Iteration Group 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
            
               
                   
                 Real Time 
                 T1-CIR 
                 T1-EIR 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                 Normal 
                 20 
                 40 
                 50 
               
               
                 Fail 
               
               
                 AB 
               
               
                 Fail 
                 (MAX ( 20 ,  50 ) + 30) = 80 
                 (MAX ( 40 ,  10 ) + 50) = 90 
                 (MAX ( 50 ,  80 ) + 200 = 280 
               
               
                 BC 
               
               
                 Fail 
                 (MAX ( 20 ,  50 ) + 30) = 80 
                 (MAX ( 40 ,  10 ) + 50) = 90 
                 (MAX ( 50 ,  80 ) + 200 = 280 
               
               
                 CD 
               
               
                 Fail 
               
               
                 DA 
               
               
                   
               
            
           
         
       
     
     Here it is seen that the reference information for LSP 1  in Table 9 is useful for identifying the arguments of the MAX( ) function. In Table 10, the values from LSP 1  are in italics, and the values from LSP 3  are underlined. Note that the CIR and EIR values from LSP 1  are for the normal case, not the failure-protected case, whereas the CIR and EIR values from LSP 3  are for the failure-protected case, because it is LSP 3  that is reconfigured in the event of “BC” and/or “CD” failure. 
     And finishing with the fourth iteration group using LSP 4  fields: 
     
       
         
           
               
             
               
                 TABLE 11 
               
             
            
               
                   
               
               
                 Fourth iteration group in Bandwidth Allocation 
               
               
                 Database for LSP Example 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                   
                 Tunnel 
                 Tunnel 
                 Tunnel 
                 Configured 
                 Prot 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                   
                 ID 
                 Src 
                 Dest 
                 Ringlet 
                 Method 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 LSP1 
                 1 
                 D 
                 B 
                 Outer 
                 none 
                 20 
                 40 
                 50 
                 30 
                 40 
               
               
                 LSP2 
                 2 
                 D 
                 B 
                 Inner 
                 SteerR 
                 30 
                 100 
                 200 
                 50 
                 200  
               
               
                 LSP3 
                 1 
                 D 
                 B 
                 Inner 
                 SteerR 
                 50 
                 60 
                 70 
                 10 
                 80 
               
               
                 LSP4 
                 3 
                 C 
                 B 
                 Inner 
                 SteerR 
                   100   
                 200 
                 60 
                 
                   90 
                 
                 
                   10 
                 
               
               
                   
               
            
           
         
       
     
     Once again, in Table 11, fields for LSP 1 , LSP 2 , and LSP 3  are also featured for convenient reference, although they are not used in this iteration. The applicable field values in this iteration are underlined in Table 11. 
     It is seen in  FIG. 4 , in the event of a “BC” failure, LSP 4   415  will be reconfigured from the inner “CB” ringlet to use the outer ringlet via node “A”  401 . A “CD” failure, however, will not affect LSP 4   415 . The final aggregate bandwidth database is thus: 
     
       
         
           
               
             
               
                 TABLE 12 
               
             
            
               
                   
               
               
                 Aggregate Bandwidth Database for LSP Example - 
               
               
                 after 4 th  Iteration Group 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 Real Time 
                 T1-CIR 
                 T1-EIR 
               
               
                   
                   
               
               
                   
                 Normal 
                 20 
                 40 
                  50 
               
               
                   
                 Fail 
               
               
                   
                 AB 
               
               
                   
                 Fail 
                 80 +  100  = 180 
                 90 +  90  = 180 
                 280 +  10  = 290 
               
               
                   
                 BC 
               
               
                   
                 Fail 
                 80 
                 90 
                 280 
               
               
                   
                 CD 
               
               
                   
                 Fail 
               
               
                   
                 DA 
               
               
                   
                   
               
            
           
         
       
     
     Therefore, the aggregate bandwidth database for node “A”  401  as used for traffic management is: 
     
       
         
           
               
             
               
                 TABLE 13 
               
             
            
               
                   
               
               
                 Deliverable Node “A” Aggregate Bandwidth 
               
               
                 Database for LSP Example 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
            
               
                   
                 Real Time 
                 T1-CIR 
                 T1-EIR 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 Normal 
                 20 
                 40 
                 50 
               
               
                   
                 Fail 
               
               
                   
                 AB 
               
               
                   
                 Fail 
                 180 
                 180 
                 290 
               
               
                   
                 BC 
               
               
                   
                 Fail 
                 80 
                 90 
                 280 
               
               
                   
                 CD 
               
               
                   
                 Fail 
               
               
                   
                 DA 
               
               
                   
                   
               
            
           
         
       
     
     Predetermined Rules for VPLS Aggregation 
     According to an embodiment of the present invention, the aggregation rules for VPLS are simplified by aggregating unicast, multicast, and broadcast traffic in the same manner, by considering only the source of the traffic, but not the destination. This simplification is a conservative approach to bandwidth aggregation, representing the worst-case situation: VPLS traffic is aggregated throughout the entire ring (subject to the predetermined rules, of course), even if the VPLS utilizes only a portion of the ring. In addition to simplifying the calculations, this approach allows for the possibility of adding a node of the ring to support expansion of the Virtual LAN. 
     According to an embodiment of the present invention, predetermined rules for VPLS rate aggregation include:
         Each VPLS bandwidth allocation field shall be added to the corresponding traffic bandwidth for the normal case, except that bandwidth allocation for the source node shall not be added.   For non-protected cases, bandwidth allocations shall not be added in any case of segment failure.   For steer-revertive cases, the corresponding protected traffic bandwidth allocations shall be added, except for the source node.       

     In this non-limiting example, an aggregate bandwidth database is generated for node “A”  501 . (The previous comments in the LSP example above, pertaining to the generating of similar aggregate bandwidth databases for the other nodes of ring  500  are also applicable in this case.) 
     VPLS Example 
     A non-limiting example is illustrated in  FIG. 5 . A ring network  500  has a node “A”  501 , a node “B”  503 , a node “C”  505 , and a node “D”  507 . 
     A virtual private LAN service (VPLS), denoted as VPLS 1   519  has a device  511  connected to node “D”  507 , a device  513  connected to node “A”  501 , a device  515  connected to node “B”  503 , and a device  517  connected to node “C”  505 . The virtual LAN connections  519  between the respective devices  511 ,  513 ,  515 , and  517  are implemented physically by ring network  500 . 
     Similarly, a VPLS denoted as VPLS 2   529  has a device  521  connected to node “D”  507 , a device  523  connected to node “A”  501 , and a device  525  connected to node “B”  503 . The virtual LAN connections  529  between the respective devices  521 ,  523 , and  525  are also implemented physically by ring network  500 . 
     For this non-limiting example, the bandwidth allocation database is shown in Table 14. Note that in all cases, the protection is steer revertive, and as previously discussed, only the VPLS source is taken into account; the VPLS destination is not considered when aggregating rates. 
     
       
         
           
               
             
               
                 TABLE 14 
               
             
            
               
                   
               
               
                 Bandwidth Allocation Database for VPLS Example 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                 VPLS 
                 VPLS 
                 Configured 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                 ID 
                 Source 
                 Ringlet 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 1 
                 D 
                 Outer 
                 50 
                 20 
                 70 
                 10 
                 40 
               
               
                 1 
                 A 
                 Inner 
                 60 
                 30 
                 80 
                 20 
                 50 
               
               
                 1 
                 B 
                 Outer 
                 70 
                 40 
                 90 
                 30 
                 60 
               
               
                 1 
                 C 
                 Inner 
                 80 
                 50 
                 100 
                 40 
                 70 
               
               
                 2 
                 D 
                 Inner 
                 90 
                 60 
                 110 
                 50 
                 80 
               
               
                 2 
                 A 
                 Outer 
                 100 
                 70 
                 120 
                 60 
                 90 
               
               
                 2 
                 B 
                 Inner 
                 110 
                 80 
                 130 
                 70 
                 100 
               
               
                   
               
            
           
         
       
     
     As done previously for the LSP example and as indicated in initialization step  205  of  FIG. 2A , we begin by initializing the aggregate bandwidth database for node “A”  501 . In contrast to the LSP example, however, both the outer and inner ringlets are of interest, as shown in Table 15. 
     
       
         
           
               
             
               
                 TABLE 15 
               
             
            
               
                   
               
               
                 Initialized Aggregate Bandwidth Database 
               
               
                 for VPLS Example 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
            
               
                   
                 Real Time 
                 T1-CIR 
                 T1-EIR 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                   
                 Outer 
                 Normal 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 AB 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 BC 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 CD 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 DA 
               
               
                   
                 Inner 
                 Normal 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 AB 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 BC 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 CD 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 DA 
               
               
                   
                   
               
            
           
         
       
     
     Next, to iterate through the various fields of the Bandwidth Allocation Database (as indicated by loop entry point  207  of  FIG. 2A ), we start with the first VPLS 1  entry from Table 14 as shown in Table 16: 
     
       
         
           
               
             
               
                 TABLE 16 
               
             
            
               
                   
               
               
                 First iteration group in Bandwidth Allocation 
               
               
                 Database for VPLS Example 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                 VPLS 
                 VPLS 
                 Configured 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                 ID 
                 Source 
                 Ringlet 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
               
               
                 1 
                 D 
                 Outer 
                 
                   50 
                 
                 
                   20 
                 
                 
                   70 
                 
                 
                   10 
                 
                 
                   40 
                 
               
               
                   
               
            
           
         
       
     
     After iterating on the applicable fields of Table 16 according to the predetermined rules for VPLS aggregation as presented above, the Aggregate Bandwidth Database is: 
     
       
         
           
               
             
               
                 TABLE 17 
               
             
            
               
                   
               
               
                 Aggregate Bandwidth Database for VPLS Example - 
               
               
                 after 1 st  Iteration Group 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
            
               
                   
                 Real Time 
                 T1-CIR 
                 T1-EIR 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Outer 
                 Normal 
                 
                   50 
                 
                 
                   20 
                 
                 
                   70 
                 
               
               
                   
                   
                 Fail 
                 
                   50 
                 
                 
                   10 
                 
                 
                   40 
                 
               
               
                   
                   
                 AB 
               
               
                   
                   
                 Fail 
                 
                   50 
                 
                 
                   10 
                 
                 
                   40 
                 
               
               
                   
                   
                 BC 
               
               
                   
                   
                 Fail 
                 
                   50 
                 
                 
                   10 
                 
                 
                   40 
                 
               
               
                   
                   
                 CD 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 DA 
               
               
                   
                 Inner 
                 Normal 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 AB 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 BC 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 CD 
               
               
                   
                   
                 Fail 
                 
                   50 
                 
                 
                   10 
                 
                 
                   40 
                 
               
               
                   
                   
                 DA 
               
               
                   
                   
               
            
           
         
       
     
     Proceeding to the second VPLS 1  entry from Table 14, the iteration group is shown in Table 18: 
     
       
         
           
               
             
               
                 TABLE 18 
               
             
            
               
                   
               
               
                 Second iteration group in Bandwidth Allocation 
               
               
                 Database for VPLS Example 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                 VPLS 
                 VPLS 
                 Configured 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                 ID 
                 Source 
                 Ringlet 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
               
               
                 1 
                 A 
                 Inner 
                 60 
                 30 
                 80 
                 20 
                 50 
               
               
                   
               
            
           
         
       
     
     This second iteration results in: 
     
       
         
           
               
             
               
                 TABLE 19 
               
             
            
               
                   
               
               
                 Aggregate Bandwidth Database for VPLS Example - 
               
               
                 after 2 nd  Iteration Group 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
            
               
                   
                 Real Time 
                 T1-CIR 
                 T1-EIR 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Outer 
                 Normal 
                 50 
                 20 
                 70 
               
               
                   
                   
                 Fail 
                 50 
                 10 
                 40 
               
               
                   
                   
                 AB 
               
               
                   
                   
                 Fail 
                 50 
                 10 
                 40 
               
               
                   
                   
                 BC 
               
               
                   
                   
                 Fail 
                 50 
                 10 
                 40 
               
               
                   
                   
                 CD 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 DA 
               
               
                   
                 Inner 
                 Normal 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 AB 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 BC 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 CD 
               
               
                   
                   
                 Fail 
                 50 
                 10 
                 40 
               
               
                   
                   
                 DA 
               
               
                   
                   
               
            
           
         
       
     
     It is seen that Table 19 is identical to Table 17, because we are aggregating bandwidth requirements for node “A”  501 , and the source in Table 18 is also node “A”  501 . As previously presented in the general predetermined rules, the bandwidths for the source node are not added. 
     Proceeding to the third VPLS 1  entry from Table 14, the iteration group is shown in Table 18: 
     
       
         
           
               
             
               
                 TABLE 20 
               
             
            
               
                   
               
               
                 Third iteration group in Bandwidth Allocation 
               
               
                 Database for VPLS Example 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                 VPLS 
                 VPLS 
                 Configured 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                 ID 
                 Source 
                 Ringlet 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
               
               
                 1 
                 B 
                 Outer 
                 
                   70 
                 
                 
                   40 
                 
                 
                   90 
                 
                 
                   30 
                 
                 
                   60 
                 
               
               
                   
               
            
           
         
       
     
     This third iteration results in: 
     
       
         
           
               
             
               
                 TABLE 21 
               
             
            
               
                   
               
               
                 Aggregate Bandwidth Database for VPLS Example - 
               
               
                 after 3 rd  Iteration Group 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
            
               
                   
                 Real Time 
                 T1-CIR 
                 T1-EIR 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Outer 
                 Normal 
                 50 +  70  = 120 
                 20 +  40  = 60 
                 70 +  90  = 160 
               
               
                   
                 Fail 
                 50 +  70  = 120 
                 10 +  30  = 40 
                 40 +  60  = 100 
               
               
                   
                 AB 
               
               
                   
                 Fail 
                 50 
                 10 
                 40 
               
               
                   
                 BC 
               
               
                   
                 Fail 
                 50 
                 10 
                 40 
               
               
                   
                 CD 
               
               
                   
                 Fail 
               
               
                   
                 DA 
               
               
                 Inner 
                 Normal 
               
               
                   
                 Fail 
               
               
                   
                 AB 
               
               
                   
                 Fail 
                 
                   70 
                 
                 
                   30 
                 
                 
                   60 
                 
               
               
                   
                 BC 
               
               
                   
                 Fail 
                 
                   70 
                 
                 
                   30 
                 
                 
                   60 
                 
               
               
                   
                 CD 
               
               
                   
                 Fail 
                 50 +  70  = 120 
                 10 +  30  = 40 
                 40 +  60  = 100 
               
               
                   
                 DA 
               
               
                   
               
            
           
         
       
     
     Proceeding to the fourth and last VPLS 1  entry from Table 14, the iteration group is shown in Table 22: 
     
       
         
           
               
             
               
                 TABLE 22 
               
             
            
               
                   
               
               
                 Fourth iteration group in Bandwidth Allocation 
               
               
                 Database for VPLS Example 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                 VPLS 
                 VPLS 
                 Configured 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                 ID 
                 Source 
                 Ringlet 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
               
               
                 1 
                 C 
                 Inner 
                 
                   80 
                 
                 
                   50 
                 
                 
                   100 
                 
                 
                   40 
                 
                 
                   70 
                 
               
               
                   
               
            
           
         
       
     
     This fourth iteration results in: 
     
       
         
           
               
             
               
                 TABLE 23 
               
             
            
               
                   
               
               
                 Aggregate Bandwidth Database for VPLS Example - 
               
               
                 after 4 th  Iteration Group 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
            
               
                   
                 Real Time 
                 T1-CIR 
                 T1-EIR 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Outer 
                 Normal 
                 120  
                 60 
                 160 
               
               
                   
                 Fail 
                 120 +  80  = 200 
                 40 +  40  = 80 
                 100 +  70  = 170 
               
               
                   
                 AB 
               
               
                   
                 Fail 
                  50 +  80  = 130 
                 10 +  40  = 50 
                  40 +  70  = 110 
               
               
                   
                 BC 
               
               
                   
                 Fail 
                 50 
                 10 
                  40 
               
               
                   
                 CD 
               
               
                   
                 Fail 
               
               
                   
                 DA 
               
               
                 Inner 
                 Normal 
                 80 
                 50 
                 100 
               
               
                   
                 Fail 
               
               
                   
                 AB 
               
               
                   
                 Fail 
                 70 
                 30 
                  60 
               
               
                   
                 BC 
               
               
                   
                 Fail 
                  70 + 80 = 150 
                 30 + 40 = 70 
                  60 + 70 = 130 
               
               
                   
                 CD 
               
               
                   
                 Fail 
                 120 +  80  = 200 
                 40 +  40  = 80 
                 100 +  70  = 170 
               
               
                   
                 DA 
               
               
                   
               
            
           
         
       
     
     At this point, there are three more iterations to perform, for the bandwidth allocations of VPLS 2 . 
     Proceeding to the first VPLS 2  entry from Table 14, the iteration group is shown in Table 24: 
     
       
         
           
               
             
               
                 TABLE 24 
               
             
            
               
                   
               
               
                 Fifth iteration group in Bandwidth Allocation 
               
               
                 Database for VPLS Example 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                 VPLS 
                 VPLS 
                 Configured 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                 ID 
                 Source 
                 Ringlet 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
               
               
                 2 
                 D 
                 Inner 
                 90 
                 60 
                 110 
                 50 
                 80 
               
               
                   
               
            
           
         
       
     
     This fifth iteration results in: 
     
       
         
           
               
             
               
                 TABLE 25 
               
             
            
               
                   
               
               
                 Aggregate Bandwidth Database for VPLS Example - 
               
               
                 after 5 th  Iteration Group 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
            
               
                   
                 Real Time 
                 T1-CIR 
                 T1-EIR 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Outer 
                 Normal 
                 120 
                 60 
                 160 
               
               
                   
                 Fail 
                 200 +  90  = 290 
                 80 +  50  = 130 
                 170 +  80  = 250 
               
               
                   
                 AB 
               
               
                   
                 Fail 
                 130 +  90  = 220 
                 50 +  50  = 100 
                 110 +  80  = 190 
               
               
                   
                 BC 
               
               
                   
                 Fail 
                  50 +  90  = 140 
                 10 +  50  = 60 
                  40 +  80  = 120 
               
               
                   
                 CD 
               
               
                   
                 Fail 
               
               
                   
                 DA 
               
               
                 Inner 
                 Normal 
                  80 +  90  = 170 
                 50 +  60  = 110 
                 100 +  110  = 210  
               
               
                   
                 Fail 
               
               
                   
                 AB 
               
               
                   
                 Fail 
                  70 
                 30 
                  60 
               
               
                   
                 BC 
               
               
                   
                 Fail 
                 150 
                 70 
                 130 
               
               
                   
                 CD 
               
               
                   
                 Fail 
                 200 +  90  = 290 
                 80 +  50  = 130 
                 170 +  80  = 250 
               
               
                   
                 DA 
               
               
                   
               
            
           
         
       
     
     Proceeding to the second VPLS 2  entry from Table 14, the iteration group is shown in Table 26: 
     
       
         
           
               
             
               
                 TABLE 26 
               
             
            
               
                   
               
               
                 Sixth iteration group in Bandwidth Allocation 
               
               
                 Database for VPLS Example 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                 VPLS 
                 VPLS 
                 Configured 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                 ID 
                 Source 
                 Ringlet 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
               
               
                 2 
                 A 
                 Outer 
                 100 
                 70 
                 120 
                 60 
                 90 
               
               
                   
               
            
           
         
       
     
     This sixth iteration results in: 
     
       
         
           
               
             
               
                 TABLE 27 
               
             
            
               
                   
               
               
                 Aggregate Bandwidth Database for VPLS Example - 
               
               
                 after 6 th  Iteration Group 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
            
               
                   
                 Real Time 
                 T1-CIR 
                 T1-EIR 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Outer 
                 Normal 
                 120 
                 60 
                 160 
               
               
                   
                   
                 Fail 
                 290 
                 130 
                 250 
               
               
                   
                   
                 AB 
               
               
                   
                   
                 Fail 
                 220 
                 100 
                 190 
               
               
                   
                   
                 BC 
               
               
                   
                   
                 Fail 
                 140 
                 60 
                 120 
               
               
                   
                   
                 CD 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 DA 
               
               
                   
                 Inner 
                 Normal 
                 170 
                 110 
                 210 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 AB 
               
               
                   
                   
                 Fail 
                 70 
                 30 
                 60 
               
               
                   
                   
                 BC 
               
               
                   
                   
                 Fail 
                 150 
                 70 
                 130 
               
               
                   
                   
                 CD 
               
               
                   
                   
                 Fail 
                 290 
                 130 
                 250 
               
               
                   
                   
                 DA 
               
               
                   
                   
               
            
           
         
       
     
     It is seen that Table 27 is identical to Table 25, because we are aggregating bandwidth requirements for node “A”  501 , and the source in Table 26 is also node “A”  501 . As previously presented in the general predetermined rules, the bandwidths for the source node are not added. 
     Finally, proceeding to the third VPLS 2  entry from Table 14, the iteration group is shown in Table 28: 
     
       
         
           
               
             
               
                 TABLE 28 
               
             
            
               
                   
               
               
                 Seventh iteration group in Bandwidth Allocation 
               
               
                 Database for VPLS Example 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                 T1 
                 T1 
               
               
                 VPLS 
                 VPLS 
                 Configured 
                 RT 
                 T1 
                 T1 
                 CIR 
                 EIR 
               
               
                 ID 
                 Source 
                 Ringlet 
                 Rate 
                 CIR 
                 EIR 
                 Prot 
                 Prot 
               
               
                   
               
               
                 2 
                 B 
                 Inner 
                 
                   110 
                 
                 
                   80 
                 
                 
                   130 
                 
                 
                   70 
                 
                 
                   100 
                 
               
               
                   
               
            
           
         
       
     
     This seventh and final iteration results in: 
     
       
         
           
               
             
               
                 TABLE 29 
               
             
            
               
                   
               
               
                 Aggregate Bandwidth Database for VPLS Example - 
               
               
                 after 7 th  Iteration Group 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
            
               
                   
                 Real Time 
                 T1-CIR 
                 T1-EIR 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Outer 
                 Normal 
                 120 
                 60 
                 160 
               
               
                   
                 Fail 
                 290 +  110  = 400 
                 130 +  70  = 200 
                 250 +  100  = 350 
               
               
                   
                 AB 
               
               
                   
                 Fail 
                 220 
                 100  
                 190 
               
               
                   
                 BC 
               
               
                   
                 Fail 
                 140 
                 60 
                 120 
               
               
                   
                 CD 
               
               
                   
                 Fail 
               
               
                   
                 DA 
               
               
                 Inner 
                 Normal 
                 170 +  110  = 280 
                 110 +  80  = 190 
                 210 +  130  = 340 
               
               
                   
                 Fail 
               
               
                   
                 AB 
               
               
                   
                 Fail 
                  70 +  110  = 180 
                  30 +  70  = 100 
                  60 +  100  = 160 
               
               
                   
                 BC 
               
               
                   
                 Fail 
                 150 +  110  = 260 
                  70 +  70  = 140 
                 130 +  130  = 230 
               
               
                   
                 CD 
               
               
                   
                 Fail 
                 290 +  110  = 400 
                 130 +  70  = 200 
                 250 +  100  = 350 
               
               
                   
                 DA 
               
               
                   
               
            
           
         
       
     
     Therefore, the aggregate bandwidth database for node “A”  501  as used for traffic management is: 
     
       
         
           
               
             
               
                 TABLE 30 
               
             
            
               
                   
               
               
                 Deliverable Node “A” Aggregate Bandwidth 
               
               
                 Database for VPLS Example 
               
            
           
           
               
               
            
               
                   
                 Assured Forwarding 
               
            
           
           
               
               
               
               
            
               
                   
                 Real Time 
                 T1-CIR 
                 T1-EIR 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Outer 
                 Normal 
                 120 
                 60 
                 160 
               
               
                   
                   
                 Fail 
                 400 
                 200 
                 350 
               
               
                   
                   
                 AB 
               
               
                   
                   
                 Fail 
                 220 
                 100 
                 190 
               
               
                   
                   
                 BC 
               
               
                   
                   
                 Fail 
                 140 
                 60 
                 120 
               
               
                   
                   
                 CD 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 DA 
               
               
                   
                 Inner 
                 Normal 
                 280 
                 190 
                 340 
               
               
                   
                   
                 Fail 
               
               
                   
                   
                 AB 
               
               
                   
                   
                 Fail 
                 180 
                 100 
                 160 
               
               
                   
                   
                 BC 
               
               
                   
                   
                 Fail 
                 260 
                 140 
                 230 
               
               
                   
                   
                 CD 
               
               
                   
                   
                 Fail 
                 400 
                 200 
                 350 
               
               
                   
                   
                 DA 
               
               
                   
                   
               
            
           
         
       
     
     Computer Program Product 
     A further embodiment of the present invention provides a computer program product for performing a method disclosed in the present application or any variant derived therefrom. A computer program product according to this embodiment includes a set of executable commands for a computer, and is incorporated within tangible and persistent machine-readable data storage including, but not limited to: computer media of any kind, such as magnetic media and optical media; computer memory; semiconductor memory storage; flash memory storage; data storage devices; and a computer or communications network. The terms “perform”, “performing”, etc., and “run”, “running”, when used with reference to a computer program product herein denote the action of a computer when executing the computer program product, as if the computer program product were performing the actions. The term “computer” herein denotes any data processing apparatus capable of, or configured for, executing a set of executable commands to perform a method, including, but not limited to: computers; workstations; servers; gateways; routers; switches; networks; processors; controllers; and other devices capable of processing data. 
     While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.