1. A network device comprising: a first interface to receive, from a first network, a plurality of packets destined for a second network; a controller to transfer, via a first bus and within the network device, a first packet, of the plurality of packets, from the first interface to a memory in the network device; and a processor, connected to the memory via the first bus and via a second bus of the network device, to: determine whether the first bus is available, retrieve, via the first bus, the first packet from the memory when the first bus is available, retrieve, via the second bus, the first packet from the memory when the first bus is not available, the second bus being different than the first bus, the second bus connecting the processor to the memory without connecting the controller to the memory, and perform a plurality of operations on the first packet, the plurality of operations including one or more authentication operations, one or more encryption operations, one or more decryption operations, one or more virtual private network (VPN) processing operations, or one or more firewall operations, when performing the plurality of operations on the first packet, the processor is to perform a first operation and a second operation, of the plurality of operations, on the first packet in parallel, the first operation including one of: an authentication operation of the one or more authentication operations, or an encryption operation, of the one or more encryption operations, or a decryption operation of the one or more decryption operations, and the second operation being different than the first operation and including a different one of the authentication operation, the encryption operation, or the decryption operation.