Distributed network subnet

摘要

In general, techniques for facilitating a distributed network (L3) subnet by which multiple independent control planes of network devices connected to physically separate L2 networks provide L2 reachability to/from a single L3 subnet. In some examples, a shared L2 network physically situated to connect a plurality of physically separate L2 networks “stitches” the L2 networks together within the respective, independent control planes of switches such that the control planes bridge L2 traffic for a single bridge domain for the separate L2 networks to the shared L2 network and visa-versa. Each of the independent control planes may be configured with a virtual IRB instance associated with the bridge domain and with a common network subnet. Each of the virtual IRBs provides a functionally similar routing interface for the single bridge domain for the separate L2 networks and allows the shared network subnet to be distributed among the independent control planes.

主权项

1. A method comprising: establishing, within a first network device, a first virtual integrated routing and bridging (VIRB) interface that comprises a first routing interface for a first layer two (L2) bridge domain that provides L2 connectivity for a first network local to the first network device, wherein the first routing interface is associated with a network subnet for the first network; establishing, within a second network device, a second VIRB interface that comprises a second routing interface for a second L2 bridge domain that provides L2 connectivity for a second network local to the second network device, wherein the second routing interface is associated with a network subnet for the second network, wherein the first network is not local to the second network device and the second network is not local to the first network device, wherein the network subnet for the first network and the network subnet for the second network comprise a distributed network subnet in which the network subnet for the first network and the network subnet for the second network comprise a common network subnet, and wherein the first VIRB interface and the second VIRB interface have a common gateway MAC address that identifies routable L2 traffic received by the first VIRB interface from the first L2 bridge domain or received by the second VIRB interface from the second L2 bridge domain; receiving first L2 traffic with the first network device from the first L2 bridge domain and forwarding L3 traffic encapsulated by the first L2 traffic by the first routing interface when the first L2 traffic is destined for the common gateway MAC address; and receiving second L2 traffic with the second network device from the second L2 bridge domain and forwarding L3 traffic encapsulated by the second L2 traffic by the second routing interface when the second L2 traffic is destined for the common gateway MAC address.