Abstract: One embodiment of the present invention provides a switch. The switch includes a fabric switch module and a learning module. The fabric switch module maintains a membership in a first fabric switch. A fabric switch includes a plurality of switches and operates as a single switch. The first fabric switch is in an extended fabric switch which further comprises a second fabric switch. The learning module identifies from a notification message from the second fabric switch a media access control (MAC) address learned at the second fabric switch. The learning module stores the MAC address in a local MAC table in association with an Internet Protocol (IP) address of the second fabric switch.

Abstract: Techniques for end-to-end network bandwidth optimization using software defined networking are provided. In one embodiment, a computer system can receive information regarding a flow to be admitted to a network, where the flow is associated with a source and a destination. The computer system can further calculate, for each path in a plurality of paths between the source and the destination, a projected utilization of the path in view of the flow. If the projected utilization of the shortest path in the plurality of paths is less than or equal to a target utilization threshold, the computer system can assign the flow to the shortest path. Otherwise, the computer system can select a path in the plurality of paths that comes closest to the target utilization threshold without exceeding the threshold and can assign the flow to that selected path.

Abstract: Techniques for optimizing traffic flows via dynamic routing protocol (DRP) modifications when server virtualization is used with dynamic routing are provided. In one embodiment, a network device can determine that it is part of a system of network devices acting as a virtual router. The network device can then transmit, to a client device, a DRP control packet that includes an interface IP address of the network device and a virtual IP address of the virtual router. In a further embodiment, the client device can receive the DRP control packet and store the interface IP address and the virtual IP address in a routing database. At the time of computing routing entries based on the routing database, the client device can replace, in entries that identify the interface IP address as the next hop, the interface IP address with the virtual IP address.

Abstract: Techniques for end-to-end network bandwidth optimization using software defined networking are provided. In one embodiment, a computer system can receive information regarding a flow to be admitted to a network, where the flow is associated with a source and a destination. The computer system can further calculate, for each path in a plurality of paths between the source and the destination, a projected utilization of the path in view of the flow. If the projected utilization of the shortest path in the plurality of paths is less than or equal to a target utilization threshold, the computer system can assign the flow to the shortest path. Otherwise, the computer system can select a path in the plurality of paths that comes closest to the target utilization threshold without exceeding the threshold and can assign the flow to that selected path.

Abstract: Techniques for end-to-end network bandwidth optimization using software defined networking are provided. In one embodiment, a computer system can receive information regarding a flow to be admitted to a network, where the flow is associated with a source and a destination. The computer system can further calculate, for each path in a plurality of paths between the source and the destination, a projected utilization of the path in view of the flow. If the projected utilization of the shortest path in the plurality of paths is less than or equal to a target utilization threshold, the computer system can assign the flow to the shortest path. Otherwise, the computer system can select a path in the plurality of paths that comes closest to the target utilization threshold without exceeding the threshold and can assign the flow to that selected path.

Abstract: One embodiment of the present invention provides a switch. The switch includes a fabric switch module and a learning module. The fabric switch module maintains a membership in a first fabric switch. A fabric switch includes a plurality of switches and operates as a single switch. The first fabric switch is in an extended fabric switch which further comprises a second fabric switch. The learning module identifies from a notification message from the second fabric switch a media access control (MAC) address learned at the second fabric switch. The learning module stores the MAC address in a local MAC table in association with an Internet Protocol (IP) address of the second fabric switch.

Abstract: Techniques for end-to-end network bandwidth optimization using software defined networking are provided. In one embodiment, a computer system can receive information regarding a flow to be admitted to a network, where the flow is associated with a source and a destination. The computer system can further calculate, for each path in a plurality of paths between the source and the destination, a projected utilization of the path in view of the flow. If the projected utilization of the shortest path in the plurality of paths is less than or equal to a target utilization threshold, the computer system can assign the flow to the shortest path. Otherwise, the computer system can select a path in the plurality of paths that comes closest to the target utilization threshold without exceeding the threshold and can assign the flow to that selected path.

Abstract: Techniques for optimizing traffic flows via dynamic routing protocol (DRP) modifications when server virtualization is used with dynamic routing are provided. In one embodiment, a network device can determine that it is part of a system of network devices acting as a virtual router. The network device can then transmit, to a client device, a DRP control packet that includes an interface IP address of the network device and a virtual IP address of the virtual router. In a further embodiment, the client device can receive the DRP control packet and store the interface IP address and the virtual IP address in a routing database. At the time of computing routing entries based on the routing database (via., e.g., a shortest path first (SPF) algorithm), the client device can replace, in entries that identify the interface IP address as the next hop, the interface IP address with the virtual IP address.

Abstract: Techniques for optimizing traffic flows via MAC synchronization when server virtualization is used with dynamic routing are provided. In one embodiment, a first network device can store an interface MAC address of a second network device in an L2 forwarding table, where the first network device and the second network device are peer nodes in an MC-LAG cluster. Further, the first network device can enable a flag for the interface MAC address in the L2 forwarding table. When the first network device receives a data packet that includes the interface MAC address of the second network device as a destination MAC address, the first network device can determine that the interface MAC address is included in the L2 forwarding table with the flag enabled. The first network device can then perform a lookup into its L3 routing table, identify a next hop destination for the data packet, and route the packet to the destination.

Abstract: A novel technique is provided for preventing routing loops by disseminating Border Gateway Protocol (BGP) attribute information in an Open Shortest Path First (OSPF) configured network. Specifically, a new OSPF sub-type-length-value (TLV) is introduced for transporting a conventional BGP autonomous system (AS) path attribute through the OSPF-configured network. Like the BGP AS-path attribute, the new OSPF AS-path sub-TLV is configured to store a set of AS numbers corresponding to the AS path of one or more advertised routes. Thus, when a network device receives an OSPF link-state advertisement (LSA) containing the novel AS-path sub-TLV, the network device determines whether it resides in an autonomous system whose AS number is stored in the sub-TLV. If so, the network device does not install the LSA's advertised routes in its link-state database since the routes, if installed, could result in routing loops.

Abstract: A SONET network terminated by routers includes working paths and backup paths. The routers pre-establishes in their link state data bases the links in both for both the working and backup paths. However, the links involved in the backup paths are given higher costs, then the links working paths, that the routers select only the links in the working path. If there is a failure in a link in a working path, an APS arrangement provides rapid switchover of the optical links so as to substitute one or more links in the corresponding backup path. This is accomplished by changing the relative costs of the working and backup links involved, so that the routers select the backup links for their routing tables.

Abstract: A technique maintains Interior Gateway Protocol (IGP) transparency of Virtual Private Network (VPN) routes when Border Gateway Protocol (BGP) is used as a Provider Edge Device (PE) to Customer Edge Device (CE) protocol in a computer network. According to the novel technique, a first CE generates a BGP advertisement to advertise one or more VPN routes of its customer network, the BGP advertisement having one or more transitive IGP attributes for the advertised routes. The first CE sends the BGP advertisement to a first PE, which then propagates the BGP advertisement among devices of a provider network maintaining the transitive IGP attributes. A second PE sends the BGP advertisement to a second CE, along with the transitive IGP attributes. Upon receiving the BGP advertisement, the second CE converts the BGP advertisement and transitive IGP attributes into corresponding IGP advertisements.

Abstract: A method for border nodes using the Border Gateway Protocol to advertise path updates to peer nodes in other domains involves calculating the update interval for each advertisement of an update of the same path to the same peer and advertising the update when the interval has expired. The update interval is the sum of the standard update interval and the unexpired portions of update intervals applied to previous unadvertised updates.

Abstract: A SONET network terminated by routers includes working paths and backup paths. The routers pre-establishes in their link state data bases the links in both for both the working and backup paths. However, the links involved in the backup paths are given higher costs, then the links working paths, that the routers select only the links in the working path. If there is a failure in a link in a working path, an APS arrangement provides rapid switchover of the optical links so as to substitute one or more links in the corresponding backup path. This is accomplished by changing the relative costs of the working and backup links involved, so that the routers select the backup links for their routing tables.

Abstract: A technique maintains Interior Gateway Protocol (IGP) transparency of Virtual Private Network (VPN) routes when Border Gateway Protocol (BGP) is used as a Provider Edge Device (PE) to Customer Edge Device (CE) protocol in a computer network. According to the novel technique, a first CE generates a BGP advertisement to advertise one or more VPN routes of its customer network, the BGP advertisement having one or more transitive IGP attributes for the advertised routes. The first CE sends the BGP advertisement to a first PE, which then propagates the BGP advertisement among devices of a provider network maintaining the transitive IGP attributes. A second PE sends the BGP advertisement to a second CE, along with the transitive IGP attributes. Upon receiving the BGP advertisement, the second CE converts the BGP advertisement and transitive IGP attributes into corresponding IGP advertisements.

Abstract: A novel technique is provided for preventing routing loops by disseminating Border Gateway Protocol (BGP) attribute information in an Open Shortest Path First (OSPF) configured network. Specifically, a new OSPF sub-type-length-value (TLV) is introduced for transporting a conventional BGP autonomous system (AS) path attribute through the OSPF-configured network. Like the BGP AS-path attribute, the new OSPF AS-path sub-TLV is configured to store a set of AS numbers corresponding to the AS path of one or more advertised routes. Thus, when a network device receives an OSPF link-state advertisement (LSA) containing the novel AS-path sub-TLV, the network device determines whether it resides in an autonomous system whose AS number is stored in the sub-TLV. If so, the network device does not install the LSA's advertised routes in its link-state database since the routes, if installed, could result in routing loops.

Abstract: A method for border nodes using the Border Gateway Protocol to advertise path updates to peer nodes in other domains involves calculating the update interval for each advertisement of an update of the same path to the same peer and advertising the update when the interval has expired. The update interval is the sum of the standard update interval and the expired portions of update intervals applied to previous unadvertised updates.