Method for the provision of gateway anycast virtual MAC reachability in extended subnets
First Claim
1. A computer implemented method for providing anycast virtual media access control (MAC) reachability in an extended subnet comprising a first layer 2 subnet and a second layer 2 subnet connected through a first bridge device on the first layer 2 subnet and a second bridge device on the second layer 2 subnet, wherein the first layer 2 subnet includes a first gateway connecting the first layer 2 subnet to a first IP network, and wherein the second layer 2 subnet includes a second gateway connecting the second layer 2 subnet to a second IP network, comprising:
- determining, at the first bridge device, a gateway MAC address associated with both a local port of the first bridge device and a LAN extension port of the first bridge device, wherein the first gateway is reachable within the first layer 2 subnet at the gateway MAC address using the local port, and wherein the second gateway is reachable within the first layer 2 subnet at the gateway MAC address using the LAN extension port;
receiving, from a host in the first layer 2 subnet, a network frame specifying the gateway MAC address as a destination address; and
selectively forwarding the received network frame to one of (i) the first gateway using the local port or (ii) the second gateway using the LAN extension port, based at least in part on the destination address.
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Accused Products
Abstract
A method and apparatus is disclosed for providing gateway anycast virtual MAC reachability in extended subnets. When an extended L2 subnet spans more than one geographical location, it is desirable that the gateway MAC addresses learned in each location be the same across all IP hosts. Accordingly, the gateway MAC address may be preserved (i.e., programmed) in more than one port on a bridge, such as both a local port and a LAN extension port. The bridge may forward traffic having the anycast MAC address to the closest instance of the MAC address, rather than replicating the traffic to the multiple ports on which the anycast MAC address is programmed. If the gateway reachable on the local port goes down, the frame may be forwarded to the local gateway in the second layer 2 subnet over the LAN extension port.
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Citations
16 Claims
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1. A computer implemented method for providing anycast virtual media access control (MAC) reachability in an extended subnet comprising a first layer 2 subnet and a second layer 2 subnet connected through a first bridge device on the first layer 2 subnet and a second bridge device on the second layer 2 subnet, wherein the first layer 2 subnet includes a first gateway connecting the first layer 2 subnet to a first IP network, and wherein the second layer 2 subnet includes a second gateway connecting the second layer 2 subnet to a second IP network, comprising:
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determining, at the first bridge device, a gateway MAC address associated with both a local port of the first bridge device and a LAN extension port of the first bridge device, wherein the first gateway is reachable within the first layer 2 subnet at the gateway MAC address using the local port, and wherein the second gateway is reachable within the first layer 2 subnet at the gateway MAC address using the LAN extension port; receiving, from a host in the first layer 2 subnet, a network frame specifying the gateway MAC address as a destination address; and selectively forwarding the received network frame to one of (i) the first gateway using the local port or (ii) the second gateway using the LAN extension port, based at least in part on the destination address. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A switch, comprising:
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a processor; and a memory containing a program which, when executed on the processor performs an operation for providing anycast virtual media access control (MAC) reachability in an extended subnet comprising a first layer 2 subnet and a second layer 2 subnet connected through a first bridge device on the first layer 2 subnet and a second bridge device on the second layer 2 subnet, wherein the first layer 2 subnet includes a first gateway connecting the first layer 2 subnet to a first IP network, and wherein the second layer 2 subnet includes a second gateway connecting the second layer 2 subnet to a second IP network, the operation comprising; determining, at the first bridge device, a gateway MAC address associated with both a local port of the first bridge device and a LAN extension port of the first bridge device, wherein the first gateway is reachable within the first layer 2 subnet at the gateway MAC address using the local port, and wherein the second gateway is reachable within the first layer 2 subnet at the gateway MAC address using the LAN extension port; receiving, from a host in the first layer 2 subnet, a network frame specifying the gateway MAC address as a destination address; and selectively forwarding the received network frame to one of (i) the first gateway using the local port or (ii) the second gateway using the LAN extension port, based at least in part on the destination address. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A non-transitory computer-readable medium, containing a program, which, when executed on a processor performs an operation for providing anycast virtual media access control (MAC) reachability in an extended subnet comprising a first layer 2 subnet and a second layer 2 subnet connected through a first bridge device on the first layer 2 subnet and a second bridge on the second layer 2 subnet, wherein the first layer 2 subnet includes a first gateway connecting the first layer 2 subnet to a first IP network, and wherein the second layer 2 subnet includes a second gateway connecting the second layer 2 subnet to a second IP network, the operation comprising:
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determining, at the first bridge device, a gateway MAC address associated with both a local port of the first bridge device and a LAN extension port of the first bridge device, wherein the first gateway is reachable within the first layer 2 subnet at the gateway MAC address using the local port, and wherein the second gateway is reachable within the first layer 2 subnet at the gateway MAC address using the LAN extension port; receiving, from a host in the first layer 2 subnet, a network frame specifying having the gateway MAC address as a destination address; and selectively forwarding the received network frame to one of (i) the first gateway using the local port or (ii) the second gateway using the LAN extension port, based at least in part on the destination address. - View Dependent Claims (16)
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Specification