The cost value of a physical link in a particular direction is shown closest to the physical node from which the packets originate for that particular direction. The link from BB to BA has a cost value of 3. While a physical link denotes the adjacency-relationship s between a pair of physical nodes, a physical path denotes a physical route a packet follows from a physical source node to a physical destination node, in case of unicast networking.
This is illustrated by some example paths in figure 2E. In case of multicast or broadcast networking there are physical path relationships between a single physical source node and multiple physical destination nodes. Physical paths can have multiple cost types in each direction with typically a cost value equal to the sum of the cost values of that particular cost type in that particular direction of the physical links it consists of. A physical path is a sequence of physical PoAs through which the packet traverses from source node to destination node.
Alternative terminology for a 'path' is a 'flow', e. Putting the above elements together, a typical representation of a physical network is illustrated in figure 2F showing the physical network BAA, physical nodes BA through BD, physical PoAs plOl through pi 08 and cost values for each physical link. In order to be able to apply a forwarding policy e. The weighted directed graph of network BAA is given in figure 2G, showing the vertices nodes BA through BD and the directed edges that connect pairs of vertices.
When represented as a directed graph, a bi-directional physical link between two vertices is represented by 2 edges. Each edge corresponds to an adjacency. Also, not forwarding blocking the packet. Virtual nodes will be explained hereafter. In order to be able to create the appropriate instructions by the SDN Compiler for the physical and virtual nodes, we will now model physical and virtual equipment typically deployed in current networks. Figure 3A depicts a physical packet forwarding system BE e. A physical packet forwarding system has one or more PoAs pi A physical packet forwarding system is represented as a physical switch node, as depicted by the functional representation given in figure 3B.
The corresponding directed graph is given in figure 3C. Figure 4A depicts non-virtualized computing equipment BF e. Non-virtualized computing equipment has one or more PoAs pi Non-virtualized computing equipment is typically in use as a physical host node, as depicted by the functional representation given in figure 4B. The corresponding directed graph is given in figure 4C. Host node BF has been split into 2 nodes: node BF in figure 4C is representing a sending host, while node BF' in figure 4C is representing a receiving host.
This distinction is made as a host node is not allowed to forward any incoming packets, as per figure 2H. The functionality of the host node of sending source packets and receiving destination packets is represented by node BF and BF', respectively, in figure 4C. Figure 5A depicts virtualized computing equipment, e. Multiple virtual machines can be connected to a single virtual switch, as illustrated by virtual machines GC and GD and virtual switch BK. A single virtual machine can be connected to multiple virtual switches, as illustrated by virtual machine GB and virtual switches B J and BK.
We will refer to this as 1 : 1, 1 :N, N: 1 physical to virtual mapping respectively. The functional model of virtualized computing equipment shown in figure 5A is depicted in figure 5B. Please note that virtual switches BJ, BK are represented as physical switch nodes and represented by the physical switch node symbol as defined in figure 21, as virtual switches BJ, BK are functionally equivalent to physical forwarding equipment.
The difference is in implementation as virtual switches BJ, BK are typically implemented in software rather than hardware. The physical to virtual mapping is denoted by a dashed line with virtual PoAs p p identifying the point-of- attachment of the virtual switch BJ, BK and of the virtual machine GA-GD. The virtual PoAs pi pl26 identify the point-of-attachments of a physical node virtual switch and of a virtual node virtual machine of a physical to virtual mapping. Figures 6A-6C show the functional representation of 1 : 1 , 1 :N and N: 1 physical to virtual mapping.
Figure 6A depicts 1 : 1 physical to virtual mapping, figure 6B depicts 1 :N physical to virtual mapping, figure 6C depicts N: 1 physical to virtual mapping. A physical to virtual mapping can have an optional cost value for each direction of the mapping. In case of physical server virtualization typically reference is made to 1 : 1, 1 :N, N: 1 virtualization, referring to the ratio of number of physical servers to virtual machines.
Please note that in the physical to virtual mapping introduced above the ratio 1 : 1, 1 :N, N: 1 is referring to the ratio of number of virtual switches to virtual machines. As depicted in figure 2H we distinguish between 2 types of virtual nodes, both being virtual machines:. The above mentioned virtual switch node allows for Network Functions Virtualization NFV : a virtual switch node is implemented in a virtual machine through which traffic is forwarded.
Typically, the virtual switch node would perform optional operations on the packet as mentioned at d above. In analogy with the physical network, we define a virtual network as a collection of virtual nodes. It is observed that we refer to 'virtual switch node' when referring to a virtual machine that has the above properties of a switch, while we refer to a 'physical switch node' when referring to the virtual switch in the virtualized physical server.
It is also observed that the virtual machines depicted in figure 5B and figures 6A, 6C can either be a virtual switch node or a virtual host node.
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As such, the crosses symbol representing a switch and the circle symbol representing a host node are omitted in these figures. Virtual machine GJ is accommodated in both instances of computing equipment. Examples of connections are shown via links between respective PoAs plpl Figure 7A illustrates some additional properties of virtualized computing equipment. As illustrated by PoAs i 46 and pi 47, virtual switches can be interconnected, represented by a physical link in figure 7B. Note this interconnection is represented by a physical link as a virtual switch is represented by a physical switch node.
As illustrated by virtual machine GJ, a virtual machine can be connected to multiple virtual switches each residing in different computing equipment instances. For redundancy purposes virtual switches are typically connected to multiple NICs. To make efficient use of the NIC resources and physical links to other computing equipment or packet forwarding systems, multiple virtual switches can be connected to a single NIC. Figure 7B depicts a functional representation of the virtualized computing equipment shown in figure 7A.
This is depicted in figures 8A-8C and 9A-9C. The functional model is shown in figure 8B. The representation in a directed graph of a NIC is given in figure 8C. In case a Network Interface Card would be used that provides switching capabilities it would be modeled as a physical switch node. The NIC is situated at the boundary of the computing equipment and provides connectivity between the resources outside the computing equipment and resources within the computing equipment.
As explained in figure 2H, the NIC is never a source or destination node of packets. The exact same representation in directed graphs applies to virtual and logical nodes as well, with this exception that virtual and logical nodes are not NIC-type nodes. Today, this functionality is typically provided by dedicated hardware devices, referred to as middle-boxes, such as but not limited to firewalls, deep packet inspection devices and caching nodes. Realizing this functionality in a virtual switch node will create benefits for example but not limited to reduced equipment costs, reduced operational costs, faster provisioning of network services.
The SDN compiler provides the relevant instructions to the virtual switch node. The NFV functions could be realized in a virtual switch node implemented in virtualized computing equipment. As mentioned above, we consider Software Defined Networking as the capability to define a network in a high-level specification such as, but not limited to, a high-level programming or scripting language and through an automated process instructing the appropriate physical and virtual networking and computing resources in accordance with this specification.
By now, we have provided a functional model of the physical and virtual networking and computing resources. Now, to illustrate the present invention, we consider a logical network that can be defined in a high-level specification and is independent from physical and virtual resources. The logical network is defined by specifying:. This is depicted in figures 10AG, as follows:. The functional representation of a logical node is a dashed circle, as depicted in figure 1 IB. The user of the SDN Compiler defines the logical network.
The user could be, but is not limited to, a person, a network management system, a cloud management system, an application, another SDN Compiler. The logical network can consist of an arbitrary number of logical nodes, with arbitrary logical adjacencies, resulting in an arbitrary logical topology. For the logical nodes, we use a logical name space that is independent from the namespace of the physical and virtual resources.
The logical network can now be defined in terms of logical node names, which may be expressed in any suitable form with any suitable number of unique characters and are mapped to the appropriate virtual and physical resources as required. By changing this mapping, the logical network can be re-mapped to other virtual and physical resources. Please note that the logical network is independent from the physical network and virtual resources, of course with the constraint a path exists between physical and virtual resources, and as such provides an abstraction of the physical network and virtual resources.
As depicted in figure 11 A we distinguish between 2 types of logical nodes:. A physical NIC is not mapped to an entity in the logical network. The complete list of node types and symbols is summarized in figure 1 IB. The functional representation of all physical nodes is shown in figure 13 A, according to the approach explained above. In figure 13 A, the weights of the various links have been added for each direction of the bi-directional link.
The collection of these physical nodes is referred to as physical network DAA. Note that the virtual switch DA is a physical switch node in the functional representation of figure 13 A. The weighted directed graph representation of the network of figure 13A is given in figure 13B. Note that PoAs p85 through p88 are virtual PoAs. Also note that the cost of both mappings is zero in both directions. In the example here, virtual machine HA provides functionality of a virtual host node, while virtual machine HB provides functionality of a virtual switch node.
We will use this example to explain the mapping of a logical network onto the virtual and physical resources. The name of the logical node is used to make forwarding decisions upon. Please note that the logical node itself is named, not its interfaces. In analogy with the physical network, we define a logical network identified with UUU in figure 15 A as a collection of logical nodes. Logical nodes are interconnected by logical links denoted by a solid line. In case a logical link is bidirectional, a logical link creates a pair of adjacencies between a pair of logical nodes. In case a logical link is unidirectional, a logical link creates a single adjacency between a pair of physical nodes.
The set of logical nodes combined with the set of logical links determines the logical topology of the network. Each logical link has one or multiple cost types and cost value s associated with each cost type. Each bidirectional logical link has 2 cost values for each cost type, one for each direction. Each unidirectional logical link has 1 cost value for each cost type.
The cost value of a logical link in a particular direction is shown closest to the logical node from which the packets originate for that particular direction. While a logical link denotes the adjacency-relationship s between a pair of logical nodes, a logical path denotes a logical route a packet follows from a logical source node to a logical destination node, in case of unicast networking. In case of multi-cast or broadcast networking there are logical path relationships between a single logical source node and multiple logical destination nodes.
Logical paths can have multiple cost types in each direction with typically a cost value equal to the sum of the cost values of that particular cost type in that particular direction of the logical links it consists of. Here we have arrived at an important relationship: a relationship between logical source and logical destination nodes and a path described in terms of physical and virtual PoA's. The weighted directed graph representation of logical network UUU is shown in figure 15B. The mapping between physical and virtual nodes to logical nodes is depicted in figure 15C.
Figure 16 summarizes the relationship between physical, virtual, logical nodes and physical and logical networks for the example given in figures 12, 13 A, 13B, 14A, 14B and 15AC. At the bottom of figure 16 physical network DAA is shown. Two virtual machines named HA virtual host node and HB virtual switch node are mapped to physical node DA 1 :2 physical to virtual mapping. In general, the number of nodes in a logical network is independent from the number physical and virtual nodes it was mapped to.
This illustrates an important property of a logical network: the links in the logical network are independent from the links in the physical network and the mapping from physical to virtual nodes. Furthermore, the cost of the adjacencies in the logical network can differ from the cost of the same adjacencies in the physical network. This allows for forwarding of packets along a particular path in the logical network that is different from the forwarding policy specified in the physical network.
This is illustrated by using a cost value of 2 in both directions on the link between logical node UV and logical node UW cf. By selecting the appropriate cost values for the adjacencies in the logical network and applying a forwarding policy within the logical network, paths can be created between logical source and logical destination nodes that traverse particular virtual machine acting as virtual switch nodes performing certain functions other than forwarding on the packet.
For completeness, we summarize the physical, virtual and logical elements. Physical elements:. The relationship between the adjacencies in a network and the paths in a network is determined by the forwarding policy of the particular network. In essence, the forwarding policy of a network provides a translation of the adjacencies in the network to a set of forwarding paths. Examples of typical policies, but not limited to, used in networking are:.
As we define the network in terms of logical components, packet forwarding decisions will be based on logical node names. Physical and virtual nodes are named solely for the purpose of identifying physical and virtual resources. Never is the physical or virtual node name used in a forwarding decision. Figure 17 depicts packet forwarding in a packet forwarding system. Each entry in the forwarding table contains: logical source node, logical destination node, input port, optional load-balancing identifier, output port. In case a particular element is not relevant for the forwarding decision e.
Alternative terminology for a 'forwarding table' is a 'flow table', e. In case of a unicast each entry specifies a single output port to which the packet is forwarded. In case of multicast or broadcast the incoming packet is forwarded to multiple output ports. This relationship is crucial as it allows for the definition and creation of a network in terms of logical components, translating into physical and virtual output ports. Also, packets can be dropped or can optionally be encapsulated and redirected to the SDN Compiler.
The forwarding behavior of the three different types of nodes we have considered, i. Figure 18 A depicts a physical or virtual switch node with the capability to: a Send packets of which it is the source node to any of the output ports based on the forwarding function f b Receive packets of which it is the destination node based on the forwarding function f c Forward an incoming packet received on any of the input ports to any of the output ports including the port on which it was received based on the forwarding function f.
Figure 18B depicts a switch node providing the capabilities of the switch node of figure 18A and. This is referred to as an Optional function' in figure 18B. A switch node can perform multiple optional functions. Please note although at a and b above packets are not forwarded, we still refer to a 'forwarding function', to have a single function to refer to. Figure 19 depicts a physical or virtual host node with the capability to: a Send packets of which it is the source node to any of the output ports based on the forwarding function f.
The physical or virtual host node does not provide any forwarding of packets. We will however refer to the function f as a forwarding function also in case of a host node to be consistent in naming of this function irrespective of node type. In case of a host node the forwarding function f specifies to which output port packets originating from the host node destined for a particular node should be sent.
Also it specifies whether incoming packets should be received or dropped. Figures 20 A, 20B, 20C depict a physical NIC node forwarding an incoming packet received on a particular input port to a particular output port, in a fixed relationship between input and output ports. Packets are forwarded according to the forwarding table, which is essentially a filter table in case of a NIC.
In an implementation, some nodes might be limited in functionality. Although this provides less functionality in the overall system, this is a working implementation. Although this results in less security, this is a working implementation. Also, as an example a host might not support a forwarding table created by the SDN Compiler at all, but receive all incoming traffic and send all traffic out on a single output port PoA. In order to create a method to be performed by the SDN compiler, the above model is now described in terms of matrices. We distinguish between the following 6 matrix types:.
We refer to the first three matrices as PoA-type matrices. We refer to the last three matrices as Cost-type matrices. All matrices have rows and columns and are indexed by node names in both the row index i and the column index j direction. Index i indicates the source node while index j indicates the destination node in the adjacency, path or mapping relationship the matrix represents.
In case of an adjacency matrix and in case of a forwarding matrix the rows and columns are indexed by the same set of nodes. The order of the nodes indexing the rows can be different than the order of the nodes indexing the columns however. In case of a mapping matrix the set of nodes indexing the rows can either be different from or be identical to the set of nodes indexing the columns.
A generic representation of a PoA-type adjacency and forwarding matrices is depicted in figure 21 A. Each element of the matrix contains one or more rows, with on each row a sequence of PoAs of the form Output Port Input Port. In case of a PoA-type adjacency matrix, this sequence of PoAs denotes the adjacency from the node indexed by row i to the node indexed by column j. Multiple adjacencies between node i and node j result in multiple rows in element i, j, each representing an adjacency.
In case no adjacency exists between node i and node j, the value of element i,j in a PoA-type adjacency matrix is 0 zero. In case a node has no adjacency with itself, the value of the corresponding element of the PoA-type adjacency matrix is 0 zero. In case of a PoA-type forwarding matrix, this sequence of PoAs denotes the path from source node i to destination node j. Multiple paths between node i and node j result in multiple rows in element i, j, each representing a path.
In case no path exists between node i and node j, the value of element i,j is 0 zero. As there is no path needed for a node to get to itself, the corresponding value of cell i,j in case index i and index j identify the same node of a PoA-type forwarding matrix has value 1 one , indicating no output port input port is needed. Examples of adjacency PoA-type matrix are shown in figures 27B and 29B. Examples of forwarding PoA-type matrix are shown in figures 27D and 29C.
A generic representation of a PoA-type mapping matrix is given in figure 22A. The mapping statement contains either one of the following values:. The value Output Port Input Port. The value ' 1 ' indicates a mapping between the node indexed by row i and the node indexed by column j, without any specified PoAs. The value '0' indicates no mapping between the node indexed by row i and the node indexed by column j. The PoA-type matrices are accompanied by Cost-type matrices. The indexing of the rows and columns of the Cost-type matrix is identical to the indexing of rows and columns of the corresponding PoA-type matrix.
A generic representation of Cost-type adjacency and forwarding matrices is depicted in figure 2 IB. The adjacency cost matrix contains the cost values of the adjacencies specified in adjacency PoA matrix it accompanies. Each PoA-type adjacency matrix can have one or more accompanying Cost-type adjacency matrices each representing a particular Cost Type. Multiple adjacencies between node i and node j result in multiple rows in element i, j each representing a cost value corresponding to the particular row in element i, j of the PoA-type adjacency matrix it accompanies.
The forwarding Cost matrix contains the cost values of the paths specified in the forwarding PoA matrix it accompanies. Each PoA-type forwarding matrix can have one or more accompanying Cost-type forwarding matrices each representing a particular Cost Type. Multiple paths between node i and node j result in multiple rows in element i, j, each representing a cost value corresponding to the particular row in element i, j of the PoA- type forwarding matrix it accompanies. As there is no path needed for a node to get to itself, the corresponding element of a Cost-type forwarding matrix is 0 zero , indicating a cost of zero.
Examples of adjacency Cost-type matrix are shown in figures 27C and 29A. Examples of forwarding Cost-type matrix are shown in figures 27E and 29D. A generic representation of a Cost-type mapping matrix is given in figure 22A. Each PoA-type mapping matrix can have one or more accompanying Cost-type mapping matrices each representing a particular Cost Type.
The mapping statement contains either one of the following values: - one or more rows, with on each row a cost value. The cost value cannot be infinity. Another type of mapping matrix is introduced as well providing a mapping between nodes and networks. A generic representation of this type of mapping matrix is given in figure 22B. The single row of this type of matrix is indexed by a network name and the columns index j are indexed by one or more node names. The value of element i,j is:. We will refer to this matrix as network-mapping matrix. The network-mapping matrix is a PoA-type matrix.
Examples of mapping matrices between a network and nodes are shown in figures 27A, 28A 28F. The operation bears similarities to standard matrix multiplication, in which the elements of a row of the first matrix are multiplied with the corresponding elements in a column of the second matrix. The matrices involved in the matrix multiplication need to be of the same type, either PoA-type or Cost-type matrices.
We first consider matrix multiplication for PoA-type matrices. For the purpose of explaining matrix multiplication these matrices are 3 by 3 matrices, however in general matrices of arbitrary number of rows and columns can be used. The columns of the first matrix and the rows of the second matrix in the matrix multiplication should be equal in number and be indexed by the same set of nodes in the same order.
Each element of RRA consists of one or more rows as depicted in figure 23B for element 'sa' consisting of q rows, as depicted in figure 23C for element 'sb' consisting of r rows , as depicted in figure 23D for element 'sc' consisting of s rows. Each element of RRB consists of one or more rows as depicted in figure 23F for element 'sk' consisting of t rows, as depicted in figure 23G for element 'sn' consisting of u rows, as depicted in figure 23H for element 'sr' consisting of w rows. In case an element consists of two or more rows, the value of any of these rows cannot be 0 zero. In essence, the sequence of PoAs of the various rows of 'sa' are appended by the sequence of PoAs of the various rows of 'sk' in all possible combinations.
All values 0 zero are removed from the matrix resulting from the matrix multiplication, unless the resulting matrix element consists of one or more rows with value 0 zero in all these rows, in which case the matrix element is set to a single row with value 0 zero. This is illustrated in figure 24D in case 'sai ' has value 1 one. The matrix multiplication operation performed on the Cost-type matrices is explained in figures 23AH and 24E, 24F, 24G. For the purpose of explaining matrix multiplication these matrices are 3 by 3 matrices, however, in general matrices of arbitrary number of rows and columns can be used.
In essence, the cost values of various rows of 'sa' are added to the cost values of the various rows of 'sk' in all possible. We illustrate matrix multiplication using the example physical network of figure 24H. Essentially, matrix multiplication of PoA-type matrices is creating paths within the network expressed in terms of PoAs. Matrix multiplication of the associated Cost-type matrices is creating the cost of that path for the particular cost type the Cost-type matrix represents. A detailed example of a SDN Compiler method for a single physical network, a single virtual network and a single logical network is depicted in figure Step 1 :.
Network AAA is a physical network comprising physical switch nodes, host nodes and NIC nodes interconnected by physical links. The physical node names, physical node types switch, host, NIC , physical links, physical PoAs, optionally physical link costs for each cost type k, virtual PoAs, optionally cost of physical to virtual mapping in the direction from physical node to virtual node for each cost type k are retrieved and stored for physical network AAA.
Depending on the implementation this information could be retrieved from a SDN controller, the nodes directly, a network management system, a network operations system, a cloud management system, other means or a combination of the above. In case the cost type is 'latency', its value is typically retrieved from measurement. In case of other cost types, its value is typically defined in an operations system. M AAA is consisting of a single row i indexed by network AAA and one or multiple columns j indexed by the nodes of AAA in which we use the nodes as they are represented in the weighted directed graph representation.
In M AAA a host is represented by 2 nodes: a host. The value of all matrix elements of M AAA is 1 one. An example of a network-mapping matrix for the network DAA of figure 16 is given in figure 27A. Examples of PoA- type adjacency matrix and Cost-type adjacency matrix, respectively, for the network DAA of figure 16 are given in figure 27B and 27C, respectively.
As mentioned above, the relationship between the adjacencies in a network and the paths in a network is determined by the forwarding policy of the particular network. Examples of typical forwarding policies are given in the description of step 4 below. An example for network DAA of figure 16 is shown in figure 27D. In essence, the forwarding policy function P of a network provides a translation of the adjacencies in the network represented by matrices A PoA and one or more A Cost of that particular network to a set of forwarding paths in the network represented by matrices F PoA and one or more F Cost of that particular network.
We will now describe examples 15 of the forwarding policy function, based on typical currently used forwarding policies, such as:. In general, the forwarding policy function P can take any form, therefore our invention is not limited to the above mentioned policies. Further, multiple policies can also be combined into an overall policy. When applying 25 forwarding policy, the specific type of the physical node, being physical switch node, physical host node or physical NIC as depicted in figure 2H and 21 should be taken into account. A SPF policy, such as e.
Dijkstra's algorithm, can be applied to the Adjacency Matrices used in our model, which represent a weighted directed graph. The PoA-type 30 matrix contains the PoAs and can be used to calculate the sequence of PoAs denoting the path, while the Cost-type matrix contains the cost value of a particular cost type for each adjacency.
A firewall policy does not allow certain paths within the network. A Specified Path policy is an explicitly stated sequence of PoAs from source node to destination node. In F PoA the sequence of PoAs is stated, while the associated cost of a particular cost type is stated in F Cost of that particular cost type.
The next policy we consider is load-balancing. Load-balancing is the ability to utilize multiple paths between a source and a destination node simultaneously. Typically, a load-balancing policy is used to split network traffic among multiple paths. Applying load-balancing can increase bandwidth between source and destination node. As depicted in figure 21A and 21B and associated description above, F POA and F Cost can contain multiple paths in a particular element i,j, of the matrix, providing the ability to load-balance traffic.
Forwarding loops are not allowed by the SDN Compiler as they would result in a packet being forwarded in a loop. In case a forwarding loop is detected, any or more of the following possible actions or other appropriate actions can be taken:. The name of each virtual node, its node type virtual switch node or virtual host node , its virtual PoAs, a physical to virtual mapping in the direction from virtual node to physical node and optionally cost of the mapping for each cost type k are retrieved and stored.
Optionally, no virtual nodes are mapped to physical network AAA. We define virtual network KKK as a set of virtual nodes. Note there are no adjacencies between the nodes of network KKK, basically network KKK is just a collection of virtual nodes. We define a set of two PoA-type mapping matrices describing the 1 : 1, 1 :N or N: 1 physical to virtual mapping depicted in figures 6A-6C and 16 and explained above.
The PoA-type mapping matrix contains value zero in all cells, representing 'no mapping', with exception of the following cells:. The PoA-type mapping matrix contains zeros, representing 'no mapping', with exception of the following cells:. We define a set of two Cost-type mapping matrices describing the 1 : 1, 1 :N or N: 1 physical to virtual mapping depicted in figures 6A-6C and 16 and explained above for cost type k.
We define logical nodes and name each logical node with a logical name. We define network VVV as a set of logical nodes. The value of all matrix elements of Mvvv is 1 one. The PoA-type mapping matrix contains value 0 zero in all cells, representing 'no mapping', with exception of the following cells:. Note that a logical host node sending host is mapped to physical or virtual host node s and the corresponding logical host' receiving host node is mapped to physical or virtual host' node s.
The PoA-type mapping matrix contains value 0 zero in all cells, representing 'no mapping', with exception of the following cells: - cell i,j contains value of 1 one in case physical or virtual node i is mapped to logical node j. Note that a physical or virtual host node is mapped to logical host node s sending host and the corresponding physical or virtual host' node is mapped to logical host' receiving host node s.
The specific type of the logical node, being logical switch node or logical host node is determined by and identical to the specific type of physical or virtual node it is mapped to as depicted in figure 11 A, 1 IB. As the above mapping matrices will typically be sparse matrices, usual formats for storing sparse matrices can be used for efficient storage of the matrices and efficient matrix multiplication operations. Step The forwarding path relationships in physical network AAA are now transformed to, preferably all, possible adjacency relationships between all logical nodes of logical network VVV by:.
In which preferably after the complete operation the value of cell i,j is set to value 0 zero in case index i and index j identify the same node. Note that the paths between physical and virtual nodes of networks AAA and KKK respectively, have been translated to possible adjacency relationships between all logical nodes of logical network VVV. Its values could be used to define the costs of adjacencies in the logical network VVV.
It is observed that this step 6 can be summarized as performing two sub-steps: a transforming paths in the physical network to paths between a set of nodes comprising the physical nodes and virtual nodes in dependence on the physical forwarding point-of-attachment relation and on a first mapping relation, as well as b transforming paths between the set of physical nodes and virtual nodes to possible link relationships between the logical nodes in dependence on the paths between the set of physical nodes and virtual nodes and on a second mapping relation.
Here, the first mapping relation defines how the virtual nodes and the physical nodes are mapped to one another, and the second mapping relation defines how the logical nodes are mapped to the physical nodes and the virtual nodes. From possible adjacency relationships resulting from step 6, we define the adjacencies of logical network VVV and optionally a Cost for each adjacency for each Cost Type n.
One or more accompanying adjacency cost matrices A Cost vvv are created, one for each Cost Type n. An example adjacency cost matrix. Hence any of the cost types can be used in the above statement to determine A PoA V vv i,j. When applying forwarding policy, the specific type of the logical node, being logical switch node or logical host node as depicted in figure 13 should be taken into account.
Examples of various forwarding policies were given in the description of step 4 above for the physical network. The same examples apply to the forwarding policy of the logical network. One or more accompanying forwarding cost matrices F Cost "wv are created, one for each Cost Type n. Any forwarding loops resulting from the applied policy Pvvv are detected by scanning each row of element i,j of forwarding matrix F PoA vw for any duplicate input ports. In terms of forwarding entries created by the SDN compiler in step 11 , they would result in multiple forwarding entries with identical logical source, logical destination and physical or virtual input ports.
In case a forwarding loop is detected, any or more of the following possible actions or other appropriate actions can be taken: - The forwarding loop is removed from the path by removing the sequence of PoAs in between the duplicate input ports as well as the first occurrence of this duplicate input port. Forwarding matrix F PoA wv contains the 'network state', being all forwarding paths between a particular logical source node and a particular logical destination node expressed in physical and virtual PoAs.
Here we use the term 'state' as typically used in computing. Forwarding matrix F PoA vvv determines the forwarding behavior of the. As an example, forwarding matrix F PoA V vv could be checked against path traces e.
Also, the 'network state' contained in forwarding matrix F PoA vvv could be stored at particular moments e. Step 3: Remove each row in forwarding matrix table F PoA Table vw and F Cost n Table vw indexed by a host' node Step 4: For each column in forwarding matrix table F PoA Table vw and forwarding cost matrix table F Cost n Table vw indexed by a host' node, copy values of matrix elements to column indexed by corresponding host node for all rows, except for the row indexed by host. The host nodes are now identified by a single node in matrices forwarding matrix table.
For each output port in forwarding matrix table F PoA Table vw create a forwarding entry for physical or virtual node to whom the output port belongs, with the following items:. A forwarding entry with input port value "local" denotes a source node, hence the packet should be sent by that node. A forwarding entry with output port value "local" denotes a destination node, hence the packet should be received by that node.
An optional load-balancing identifier can be used in case multiple paths exist between a logical source and a logical destination node in network VVV. In case multiple paths exist between a logical source and a logical destination node the corresponding element of forwarding matrix F PoA wv contains multiple rows, each containing a particular sequence of PoAs denoting a path.
As an example the load-balancer identifier could be stored in a load-balancing matrix with the same dimensions and indexing as forwarding matrix F PoA wv, with the element value being a particular load-balancing identifier associated with that path. VVV- Similarly, the SDN Compiler could maintain a matrix containing backup path s that could be used in case the path currently in use cannot be used. This will allow for fast restoration of service, avoiding recalculation of part of the process of figure The usability of the backup path obviously depends on the exact cause that makes the path currently in use unusable.
The backup path s might be unusable as well, in which case a new path to be used will result from recalculation of the process as described below. Also, higher-layer identifiers, such as but not limited to an Application Port identifier, could be used to select a particular path from multiple possible paths in forwarding matrix F M wv between a logical source node and logical destination node for that particular Application Port.
This allows for forwarding traffic for a particular application along a particular path. As an alternative to the above process to create F PoA Table vw and F Cost n Table vw, and calculate forwarding table entries from F PoA Table vw, forwarding table entries can also be calculated directly from F PoA V vv, using the process described above and: - in case a column is indexed by a host', use the name of the corresponding host in the forwarding entry instead of host'. As rows indexed by host' and columns indexed by host do not contain PoAs, no iteration is needed over rows indexed by host' and columns indexed by host.
Note that this approach is functionally equivalent to the approach described above using F PoA. Note that said forwarding table entries can be used directly by the physical or virtual nodes and do not require translation by the physical or virtual nodes. The process as described above may be, in whole or partly, be repeated when any change takes place in any physical, virtual or logical network or mapping, such as: - Physical Node, physical node type switch node, host node, NIC node , physical network, physical link, physical PoA, physical link cost type, physical link cost value, physical forwarding policy.
In the above flowchart of figure 25, we have made a distinction between the various types of nodes: switch, host and NIC.blacksmithsurgical.com/t3-assets/instruction/word-fun.php
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We introduced NIC-type and host'-type nodes in the matrices used to be able to apply the appropriate forwarding policy e. SPF in the physical network and logical network. Alternatively, we could choose not to make a distinction between the various types of nodes and not introduce the NIC '-type and host'-type nodes in the matrices used. The same process described in the flowchart of figure 25 could be applied, but when applying Forwarding Policy in step 4 and step 10 additional information would have to be added identifying the particular node type: switch, host or NIC.
In the above flowchart of figure 25, we have used PoA-type matrices of the format specified in figure 21 A. Alternatively, the 'input port' which is indicated between brackets could be omitted in the PoA-type matrices. During step 11 of the flowchart of figure 25, the appropriate physical or virtual 'input port' could be added after each physical or virtual output port in the sequence of PoAs or alternatively in the forwarding table entry.
The values of the physical input port corresponding to a particular physical output port could be obtained from the appropriate physical PoA- type adjacency matrix. The values of the virtual input port corresponding to a particular virtual output port could be obtained from the appropriate PoA-type mapping matrices representing the corresponding physical to virtual mapping. Note that the rows and columns of the defined matrices could be interchanged, which is mathematically equivalent.
The process described in the flowchart of figure 25 is summarized in the diagram of figure The PoA-type forwarding matrix of logical network VVV contains all the paths between all logical nodes in logical network VVV, expressed in terms of physical and virtual PoAs, from which the forwarding tables for all physical and virtual nodes of physical network AAA and virtual network KK are derived. In the above process depicted in figure 25, typically the user of the SDN Compiler defines inputs the following items:. Name of virtual nodes resources. By now, we have reached our objective for a Software Defined Network.
The logical network can now entirely be defined in software by the user of the SDN Compiler and can be compiled against arbitrary physical and virtual networking and computing resources, resulting in the instructions for these resources. Furthermore, our method provides a tight integration with and control over the virtual networking and computing resources, creating instructions for both networking and computing resources.
It extends the creation of forwarding tables to physical host nodes, physical NIC nodes, virtual switch nodes and virtual host nodes, beyond the usual creation of forwarding tables for physical switch nodes.
As such, the SDN Compiler becomes the central component that can optimize physical and virtual networking and computing resources based on the needs of the user s of the SDN Compiler such as e. The described SDN Compiler method may be arranged to support all 3 above methods of path instantiation. The Ethernet MAC Address is globally unique, has sufficient length 48 bits to provide a large number of addresses, is used to identify both physical and virtual PoAs and is in widespread use.
In our method, we are naming both the network and the node with a logical name. As an example, in a typical implementation the subnet part of an IPv4 address could be used to identify the logical network and the host part of an IPv4 address could be used to identify the logical node. In current networks the IPv4 and IPv6 address denotes an interface not the node. This is creating well-known limitations in IP-networking such as the multi- homing issue. This can be dealt with in 2 ways: a Use the IP address to denote a node.
As a Software Defined Network will not require any control protocols between nodes dependency on control protocols that expect the IP address to denote an interface is removed. Each logical node would be given an IP address, resulting in multiple IP- addresses for a single physical or virtual node. We now consider the naming of the logical nodes and networks. In order to make the proposed approach scalable, we introduce hierarchy in the logical naming of networks and nodes of the following form: Network-of-Networks-of-Networks.
The dot symbol ". The above naming structure introduces hierarchy in a recursive way:. This creates an arbitrary number of hierarchy-levels in the network, obviously in a deployment limited to practical constraints. Using the above structure a Node is located by: Network-of-Networks-of-Networks. And so on for various levels in the hierarchy.
This provides a means to locate the node, through it's address, within a hierarchical network. Further, the above approach abstracts every network to a node at its particular level in the naming hierarchy. A NoNs is consisting of a collection of Networks with adjacencies between Networks, in the same way as a Network is consisting of a collection of Nodes with adjacencies between nodes. Following the hierarchy of the naming structure, we can distinguish between the following types of IDNs:. The resulting forwarding table entries depict the forwarding between IDNs.
The PoA- type forwarding matrix of the network consisting of IDNs also contains the forwarding behavior for one or more nodes within the network within which the IDN resides. In this way forwarding table entries can be created for interconnection between networks, NoNs, NoNoNs, etc depending on the hierarchy level the IDNs provides. Note that within the network of IDNs policy can be applied, determining the forwarding path s between networks, NoNs, NoNoNs, etc depending on the network hierarchy level the IDNs provide interconnectivity for.
The forwarding table entries for a are derived from the PoA-type forwarding matrix of the network of the source node. The forwarding table entries for c are derived from the PoA-type forwarding matrix of network of the destination node. The same process can be repeated for each level in the hierarchy in a recursive manner. NoNoNs's etc. Note that by using the above recursive naming structure, the Adjacency, Forwarding and Mapping matrices explained above can be kept to a reasonable size, allowing for fast computation of the matrices, while the size of the network can scale to a very large number of nodes.
Also the size of the forwarding tables can be kept within reasonable limits by forwarding traffic of a collection of nodes between networks through a limited set of paths between IDNs, determined by the forwarding policy of the network of IDNs. As stated above, as an example, but not limited to, in a typical implementation consisting of a single logical network, the subnet part of an IPv4 address could be used to identify the logical network and the host part of an IPv4 address could be used to identify the logical node.
When using the logical naming hierarchy presented above to support a hierarchy of networks, as an example, but not limited to, a host part of an IPv4 address could be used to identify the logical node, while a network, NoNs, NoNoNs, etc could be denoted by Classless Inter-Domain Routing CIDR notation of the subnet of the IPv4 address.
In order to support mobility of logical nodes within the network s controlled by the SDN Compiler, the logical node should be identified by a name unique within the network s being controlled by the SDN Compiler, or be globally unique to support global mobility. As an example, but not limited to, this can be realized in any of the folio wings ways: a Splitting the IPv6 address space into a part that denotes the network, NoNs, NoNoNs, etc.
The SDN compiler method for a single physical network, a single virtual network and a single logical network as depicted in the flowchart in figure 25 is now applied to the example network depicted in figures 12, 13A, 13B, 14A, 14B, 15AC, The physical nodes of figure 12 are depicted in the functional model of figure 13A and in the weighted directed graph of figure 13B. The dashed lines in figures 14A and 16 depict this mapping which is a 1 :2 mapping between physical node DA and virtual nodes HA and HB.
The mapping cost value is zero for all mappings between physical nodes and virtual nodes in this example. The logical network UUU is depicted in figure 15 A functional representation and figure 15B graph representation. In general 1 :N or N: 1 mapping can also be applied. Embed Embed this gist in your website.
Share Copy sharable link for this gist. Learn more about clone URLs. Download ZIP. Notes For further help refer to the original vpnc. Good luck! It runs entirely in userspace. IPSec gateway This lets you put any kind of weird character except CR, LF and NUL in your strings, but it does mean you can't add comments after a string, or spaces before them. It may be easier to use the --print-config option to generate the config file, and then delete any lines like a password that you want to be prompted for. If you don't know the Group ID and Secret string, ask your administrator.
If you have a working configuration file. You need to do this yourself, or use --script "Script" in the config file. This option is passed to system , so you can use any shell-specials you like. The connection is established, but vpnc will not begin forwarding pakets until the script finishs. Note that vpnc will not forward packets anymore while the script is running or therafter. The hash value can be calculated by e. Install cygwin onto vista. Make sure you install the development options for cygwin to give you access to make and gcc etc 3. Make sure you install libcrypt for cygwin as it is needed in the make 4.
Modify the bash. Unzip and explode the tarball 6.
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You should have a shinny new vpnc. I used openvpn Solution: Fix your dhcpclient. On Debian that problem can be fixed by installing and using resolvconf to modify that file instead of modifying it directly. Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment.
You signed in with another tab or window. Reload to refresh your session. You signed out in another tab or window. IPSec ID vpnserver. IPSec gateway vpn. Supports only. Required Libraries: libgcrypt version 1. It reads configuration data from the following places:. The configuration information it currently needs is:.
Option Config file item.
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