A communication method, comprising: receiving, by a first host, a memory access address sent by a network device, wherein the memory access address points to a memory unit in a first memory pool, the network device is connected to the first host, the network device is configured to switch and forward a service of the first host, and the network device is further configured to manage the first memory pool; and when memory of the first host satisfies a preset condition, accessing, by the first host, the memory unit based on the memory access address; wherein the preset condition is any one of the following: memory usage of the first host is greater than a first threshold; remaining memory space of the first host is less than a second threshold; remaining memory space of the first host is less than memory space required for processing a service in a future target time period by the first host; or a memory usage policy of the first host is preferentially using the first memory pool; characterized in that when the first host no longer needs to use the memory unit, the method further comprises: sending, by the first host, a notification message to the network device, wherein the notification message comprises the memory access address, to enable the network device to release the memory unit. receiving, by a first host, a memory access address sent by a network device, wherein the memory access address points to a memory unit in a first memory pool, the network device is connected to the first host, the network device is configured to switch and forward a service of the first host, and the network device is further configured to manage the first memory pool; and when memory of the first host satisfies a preset condition, accessing, by the first host, the memory unit based on the memory access address; wherein the preset condition is any one of the following: memory usage of the first host is greater than a first threshold; remaining memory space of the first host is less than a second threshold; remaining memory space of the first host is less than memory space required for processing a service in a future target time period by the first host; or a memory usage policy of the first host is preferentially using the first memory pool; characterized in that when the first host no longer needs to use the memory unit, the method further comprises: sending, by the first host, a notification message to the network device, wherein the notification message comprises the memory access address, to enable the network device to release the memory unit. memory usage of the first host is greater than a first threshold; remaining memory space of the first host is less than a second threshold; remaining memory space of the first host is less than memory space required for processing a service in a future target time period by the first host; or a memory usage policy of the first host is preferentially using the first memory pool; characterized in that when the first host no longer needs to use the memory unit, the method further comprises: sending, by the first host, a notification message to the network device, wherein the notification message comprises the memory access address, to enable the network device to release the memory unit.