Secure link aggregation

A network device comprising:

• a processing resource;
• and
• a non-transitory computer-readable medium, coupled to the processing resource, having stored therein instructions that when executed by the processing resource cause the processing resource to:
• discover via a layer 2 neighbor discovery protocol device information associated with a peer network device in an untrusted domain, wherein a first interface of the network device is directly connected to a first interface of the peer network device;
• while allowing at least some network traffic to continue to be transmitted through the first interface, authenticate the peer network device;
• when the peer network device is successfully authenticated, establish a secure session between the network device and the peer network device over a first link coupling the first interface of the network device to the first interface of the peer network device;
• and
• allow the first link to operate as part of a single aggregated logical link including a second link coupling a second interface of the network device to a second interface of the peer network device.