Simple topology transparent zoning in network communications

Abstract

An autonomous system (AS) comprising a topology transparent zone (TTZ) comprising a plurality of TTZ nodes, wherein the plurality of TTZ nodes includes an edge node and an internal node, wherein each of the plurality of TTZ nodes is configured to connect to another TTZ node via an internal link, and a plurality of neighboring external nodes connected to the TTZ edge nodes via a plurality of external links, wherein no link state advertisements (LSAs) describing the internal links are distributed to the neighboring external nodes.

What is claimed is: 
     
       1. An autonomous system (AS) comprising:
 a topology transparent zone (TTZ) comprising a plurality of TTZ nodes, wherein the plurality of TTZ nodes comprises an a TTZ edge node and an a TTZ internal node, wherein each of the plurality of TTZ nodes edge node is configured to connect to another the TTZ internal node via an internal link; and 
 a plurality of neighboring external nodes connected to the TTZ edge nodes node via a plurality of external links, 
 wherein no the TTZ edge node is configured to distribute link state advertisements (LSAs) describing the internal links are distributed link to the TTZ internal node but not to the neighboring external nodes, 
 wherein the TTZ edge node is configured to distribute a plurality of first LSAs describing the plurality of external links are distributed to the plurality of neighboring external nodes, wherein the TTZ edge node is configured to distribute a plurality of second LSAs describing the plurality of external links and the plurality of internal links are distributed link to each of the plurality of TTZ nodes, and wherein each of the second LSAs comprises: 
 a LSA header comprising a link state type field specifying a router LSA type; and 
 a number of router link fields, wherein each router link field comprises a bit flag, denoted as an I bit flag, to indicate whether a link is external or internal with respect to the TTZ. 
 
     
     
       2. The AS of  claim 1 , wherein the plurality of TTZ nodes comprises at least two TTZ edge nodes including the TTZ edge node, wherein the plurality of neighboring external nodes perceives the at least two TTZ edge nodes as fully connected. 
     
     
       3. The AS of  claim 2 , wherein a cost of an internal a link between two TTZ edge nodes in the AS is a cost of a shortest path between the two TTZ edge nodes. 
     
     
       4. The AS of  claim 2 , wherein a cost of an internal a link between two TTZ edge nodes in the AS is a predetermined value. 
     
     
       5. The AS of  claim 1 , wherein a positional relationship between any two of the TTZ nodes defines an inner-topology of the TTZ, and wherein no information regarding the inner-topology is distributed to or stored in any of the plurality of neighboring external nodes. 
     
     
       6. The AS of  claim 1 , wherein an the I bit flag of is set to one indicates to indicate an internal link, and wherein an the I bit flag of is set to zero indicates to indicate an external link. 
     
     
       7. The AS of  claim 1 , wherein an the I bit flag of is set to zero indicates to indicate an internal link, and wherein an the I bit flag of is set to one indicates to indicate an external link. 
     
     
       8. The AS of  claim 1 , wherein the area AS further comprises a second TTZ comprising a second plurality of TTZ nodes, wherein the second plurality of TTZ nodes includes at least two additional TTZ edge nodes and at least one additional TTZ internal node, wherein each of the second plurality of TTZ nodes is configured to connect to another node of the second plurality of TTZ nodes via an internal link of the second TTZ, and wherein the at least two additional edge nodes are configured to receive information regarding the at least two edge nodes. 
     
     
       9. A method of configuring a topology transparent zone (TTZ) in an area of an autonomous system (AS), the method comprising:
 assigning a same TTZ identifier (ID) to a plurality of all internal links that interconnect a plurality of TTZ nodes located within the TTZ, wherein each of the plurality of internal links interconnects a pair of the plurality of TTZ nodes, wherein the plurality of TTZ nodes includes at least one edge node and at least one internal node; 
 sending a link state advertisement (LSA) from each of the at least one edge node via a plurality of external links to each of a plurality of neighboring external nodes located in the area within the AS, wherein each LSA comprises a LSA header containing a link state type field specifying a router LSA type and a number of router link fields, wherein each router link field comprises a bit flag, denoted as an I bit flag, to indicate whether a link is external or internal with respect to the TTZ, and wherein each neighboring external node is connected to at least one of the edge nodes via at least one of the external links; and 
 updating topology graphs in the neighboring external nodes based on each LSA, wherein the topology graphs describe the TTZ as the at least one edge router, and wherein the topology graphs do not contain any information regarding the at least one internal node or the plurality of internal links, wherein each LSA comprises: 
 a LSA header comprising a link state type field specifying a router LSA type; and 
 a number of router link fields, wherein each router link field comprises a bit flag, denoted as an I bit flag, to indicate whether a link is external or internal with respect to the TTZ. 
 
     
     
       10. The method of  claim 9 , wherein the plurality of TTZ nodes comprises at least two edge nodes, wherein the topology graphs describe the at least two edge routers as fully connected. 
     
     
       11. The method of  claim 9 , further comprising distributing LSAs describing an inner-topology of the TTZ over the internal links, wherein no link state information describing the inner-topology of the TTZ is distributed over the external links. 
     
     
       12. The method of  claim 9 , wherein an the I bit flag of is set to one indicates to indicate an internal link, and wherein an the I bit flag of is set to zero indicates to indicate an external link. 
     
     
       13. A router used in an area network node within a topology transparent zone (TTZ) of an autonomous system (AS) comprising:
 a first port configured to connect to a first neighboring router network node via a first link; 
 a second port configured to connect to a second neighboring router network node via a second link; 
 a memory configured to store a topology graph comprising information regarding the first and second neighboring routers, network nodes and the first and second links, 
 wherein the router network node, the first neighboring router network node, and the second neighboring router network node are located within the area AS, and 
 wherein the first neighboring router does not contain any information regarding the second neighboring router or the second link, and 
 wherein the second neighboring router contains information regarding the first neighboring router and the first link; and 
 a processor configured to:
 generate a first link state advertisement (LSA) comprising describing the first and second links; 
 
 send the first LSA to the second neighboring router network node; 
 generate a second LSA comprising describing the first link and a third link between the router network node and an additional router network node but containing no information about the second link to hide the second link from the first neighboring network node when the second LSA is received by the first neighboring network node; and 
 send the second LSA to the first neighboring router network node, and 
 wherein the additional router network node is also located within the area, and wherein the second neighboring router contains information regarding the additional router and the third link AS. 
 
     
     
       14. The router network node of  claim 13 , wherein the first LSA comprises an I bit flag with a value of one. 
     
     
       15. The router network node of  claim 13 , wherein the additional router network node is not directly connected to the router network node, and wherein the third link is a virtual link. 
     
     
       16. The router network node of  claim 13 , wherein the router and the second neighboring router are network node is located within a common topology transparent zone (TTZ) the TTZ, and wherein the first neighboring router network node is located outside the TTZ. 
     
     
       17. The network node of claim 13, wherein the information of the second link is not sent to the first neighboring network node. 
     
     
       18. The network node of claim 13, wherein the first LSA is not sent to the first neighboring network node. 
     
     
       19. The network node of claim 13, wherein the second LSA does not describe the information of the second link. 
     
     
       20. The network node of claim 13, wherein the second neighboring network node contains information regarding the additional network node and the third link. 
     
     
       21. The network node of claim 13, wherein the first LSA comprises:
 a first router link field describing the first link, wherein the first router link field comprises a bit flag to indicate the first link is external to the TTZ; and   a second router link field describing the second link, wherein the second router link field comprises a bit flag to indicate the second link is internal to the TTZ.   
     
     
       22. The network node of claim 13, wherein the first LSA comprises a number of router link fields, wherein each router link field comprises a bit flag, denoted as an I bit flag, to indicate whether a link is external or internal with respect to the TTZ. 
     
     
       23. The network node of claim 22, wherein an I bit flag of one indicates an internal link, and wherein an I bit flag of zero indicates an external link. 
     
     
       24. An autonomous system (AS) comprising:
 a topology transparent zone (TTZ) comprising a first TTZ edge node and a TTZ internal node, wherein the first TTZ edge node is connected to the TTZ internal node via an internal link; and   an external node connected to the first TTZ edge node via an external link, wherein the TTZ edge node is configured to distribute:
 a first link state advertisement (LSA) to the external node, the first LSA describing the external link but containing no information about the internal link to hide the internal link from the external node when the first LSA is received by the external node; and 
 a second LSA to the TTZ internal node, the second LSA describing the external link and the internal link and including a LSA header, the LSA header containing a link state type field and a number of router link fields, wherein each router link field comprises a bit flag, denoted as an I bit flag, to indicate whether a link is external or internal with respect to the TTZ. 
   
     
     
       25. The AS of claim 24, wherein an I bit flag of one indicates an internal link, and wherein an I bit flag of zero indicates an external link. 
     
     
       26. The AS of claim 24, wherein the TTZ further comprises a second TTZ edge node that is not directly connected to the first TTZ edge node, and wherein the first LSA describes a virtual link between the first TTZ edge node and the second TTZ edge node.