Dual adjacency between edge devices at a network site

A network device comprising:

• one or more local interfaces configured for communication, via a local network, with one or more network devices co-located in a first network site;
• one or more core interfaces configured for communication, via a core network, with one or more network devices located in one or more other network sites connected to the core network;
• and
• a processor that:
• establishes a site communication channel with a first edge device in the first network site via at least one of the local interfaces,
• establishes an overlay communication channel with the first edge device via at least one of the core interfaces such that the overlay communication channel is topologically divergent from the site communication channel, wherein the core network includes a plurality of virtual local area networks interconnecting the plurality of network sites,
• triggers an authoritative edge device election process using at least one of the site communication channel and overlay communication channel during which the device is elected as the authoritative edge device for one or more of the plurality of virtual local area networks in the core network,
• detects a failure in the local network that disables the site communication channel, and
• notifies the second edge device of the failure in the local network via the overlay communication channel.

One or more non-transitory computer readable storage media encoded with software comprising computer executable instructions and when the software is executed operable to:

• establish, at a first edge device, a site communication channel with a second edge device co-located in a first network site via a local network at the first network site, wherein the network site is configured for communication with one or more other network sites via a core network;
• establish, at the first edge device, an overlay communication channel with the second edge device via the core network such that the overlay communication channel is topologically divergent from the site communication channel, wherein the core network includes a plurality of virtual local area networks interconnecting the plurality of network sites;
• perform an authoritative edge device election process using the site communication channel and overlay communication channel such that one of the first and second edge devices is elected as the authoritative edge device for different virtual local area networks in the core network;
• detect, at the first edge device, a failure in the local network that disables the site communication channel;
• and
• notify the second edge device of the failure in the local network via the overlay communication channel.