Communication system and communication method

In a communication system, an SLG includes a slice selection unit that selects, in receiving a network slice reservation request including a network condition from a vCPE, based on topology information, a latency state, and processing capability information regarding each of the other SLGs, a destination SLG of a network slice that satisfies the network condition to reserve the network slice, and if there is no destination SLG that satisfies the network condition, newly activates a destination SLG to establish a network slice that satisfies the network condition, and an allocation unit that allocates traffic transmitted from the vCPE to the network slice reserved or established by the selection unit.